ENERGETIC AND ECOLOGICAL ASPECTS OF AGRICULTURAL

PRODUCTION

Editorial staff : Piotr F. Borowski Marek Klimkiewicz

Małgorzata Powałka

Faculty of Production Engineering Warsaw University of Life Sciences

Warsaw 2010

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Reviewers: Piotr F. Borowski Andrzej Chochowski Małgorzata Jaros Marek Klimkiewicz Adam Kupczyk Zbigniew Majewski Małgorzata Powałka

ISBN 978-83-928876-5-2 PRINT: WEMA

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CONTENTS

Chapter 1 Energy efficiency for the sustainable development of the European economy Piotr F. BOROWSKI

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Chapter 2 The chances and threats for development of ecological agriculture in Poland Mateusz ĆWIKŁA, Anna PARKA

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Chapter 3 Energy and material flow management (MFM) in agriculture Osman YALDIZ, Berk KUCUKKARA, Can ERTEKIN

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Chapter 4 Role of wind energy in agriculture Grażyna Paulina WÓJCIK

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Chapter 5 Modeling of complex highway automated control system as a tool for reducing the fuel consumption and emission in heavy-duty trucks Myroslav OLISKEVYTCH

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Chapter 6 Selective assessment of environmental side of traffic in Lvov Jevgen FORNALCHYK, Roman KACHMAR

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Chapter 7 Energy assessment of driving force generation on selected turf grassland Włodzimierz BIAŁCZYK, Anna CUDZIK, Jarosław CZARNECKI, Marek BRENNENSTHUL, Katarzyna JAMROŻY

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Chapter 8 Utilization of PID controller to steering of solar segment operation Paweł OBSTAWSKI

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Chapter 9 Using of LED lighting technologies to substitute traditional lighting systems in greenhouses Nuri CAGLAYAN, Can ERTEKIN

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Chapter 10 The influence of material homogeneity on the process of fluidized-bed drying of short rotation coppice poplar Szymon GŁOWACKI, Mariusz SOJAK

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Chapter 1

ENERGY EFFICIENCY FOR THE SUSTAINABLE DEVELOPMENT

OF THE EUROPEAN ECONOMY

Piotr F. BOROWSKI

Energy is the backbone of European prosperity, as it is vital to the functioning of every facet of our society. It is a commodity that is essential to the well-being of every citizen alike, and the right to energy is fundamental. Global energy consumption is growing rapidly and the specialists predict that the average annual rate of growth of energy consumption will be about 2%. Increasing demand across our economy has, at times, strained our energy system. The International Energy Agency projects a doubling of world electricity demand by 2030, creating the need for some 4,700 GWe of new generating capacity in the next quarter century. Worldwide energy investment will be directed primarily at satisfying local baseload requirements. Throughout the 20th century and today, the dramatic increase in energy use for industrial, residential, transportation, and other purposes has been fueled largely by the energy stored in fossil fuels and, more recently, supplied by renewable and nuclear power. So now, there is the time to work out the strategy for the future. A strategy is a long term plan of action designed to achieve a particular goal. Strategies are used to make the problem easier to understand and solve. In case of electricity production from renewables the strategy is predicated on the energy production and delivery of products and services (e.g. energy transmit). The objective is to lead the energy industry in terms of price and convenience. The strategy of electricity production is the bridge between policy or high-order goals on the one hand and tactics or concrete actions on the other. The main steps of strategy are shown in Figure 1.

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Figure 1. The main steps in strategy building process

Escalations in energy prices, increasing worldwide demand for energy, and

the need to ensure energy security have also combined to put energy in the headlines, increasing policy makers’ interest in domestically produced renewable energy. But we should remember that countries having or exporting fossil fuels cannot easily turn away from their use and likewise the economically dynamic countries of Asia cannot radically shift from fossil fuels towards uncertain and currently costly renewables for their growing baseload power needs [Borowski, 2009].

Energy efficiency when applied to the built environment can contribute greatly to a sustainable energy economy in both the short term (before 2015) and the longer term (up to 2050). Against both of these timeframes, there are a number of challenges to be addressed and technological advances to be deployed. In the short term, one of the key challenges is the delivery of energy-efficiency applications to reduce energy demands. This is dependent on energy-efficient appliances/technology being available, the cost of implementation having clear economic benefits, and users' acceptance of and willingness to implement them.

Energy is one of the most important and stable branches of industry worldwide. There is a clear link between the level of social life and energy consumption, but it must be remembered that energy is also a source of environmental degradation. Therefore, such methods are needed for extraction, processing and use of energy, which will have a minimal impact on the environment. From the perspective of the EU's energy: security, competing systems, and environmental protection are the three priority objectives for sustainable development which underlie the EU regulations in the energy field. The European Union introduces a number of regulations that contribute to proper development of the energy sector, which is a key sector of any economy. CONSERVATION, EFFICIENCY AND RENEWABLE ENERGY

Energy conservation and energy efficiency are presently the most powerful tools in our transition to a clean energy future. As depicted in the Energy Pyramid, renewable energy is very important piece of our energy future, but the opportunities are also in energy conservation and efficiency.

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THE ENERGY PYRAMID

While we strongly encourage communities first to evaluate and implement these solutions, the current focus of the word is on renewable energy generation technologies, so we have not developed materials on conservation and efficiency. We should also make conservation and efficiency our top priority, as we work to move our community into our clean energy future.

Energy conservation is achieved through efficient energy use, in which case

energy use is decreased while achieving a similar outcome, or by reduced consumption of energy services. Energy conservation may result in increase of financial capital, environmental value, national security, personal security, and human comfort. Individuals and organizations that are direct consumers of energy may want to conserve energy in order to reduce energy costs and promote economic security. Industrial and commercial users may want to increase efficiency and thus maximize profit. Electrical energy conservation is an important element of energy policy. Energy conservation reduces the energy consumption and energy demand per capita and thus offsets some of the growth in energy supply needed to keep up with population growth. This reduces the rise in energy costs, and can reduce the need for new power plants, and energy imports. The reduced energy demand can provide more flexibility in choosing the most preferred methods of energy production. By reducing emissions, energy conservation is an important part of lessening climate change. Energy conservation facilitates the replacement of non-renewable resources with renewable energy. Energy conservation is often the most economical solution to energy shortages, and is a more environmentally benign alternative to increased energy production.

A number of barriers exist to realising potential improvements of energy efficiency. The historical low cost of energy made improvement financially unattractive and also drove more profligate use of energy. Billing of fuel does not discriminate in favour of lower energy consumption – if anything, the opposite is the case, where a lower tariff can be triggered by increased fuel use. The observed phenomenon of increased winter indoor temperatures in improved buildings appears to act to reduce heating energy savings as occupants choose comfort improvement over cost saving (although this effect should saturate once all buildings reach comfortable standards and have effective heating and controls). The impact of recent

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significant increases in energy costs remains to be seen [Clarke et. al., 2008]. There are many technology options for improved energy performance and energy systems and it is not yet clear which will prove to be the most economic. Therefore, flexibility is needed in legislation and energy-efficiency initiatives.

Energy efficiency offers a powerful and cost-effective tool for achieving a sustainable energy future. Something is more energy efficient if it delivers more services for the same energy input, or the same services for less energy input. Energy efficiency in the built environment can make significant contributions to a sustainable energy economy. In order to achieve this, greater public awareness of the importance of energy efficiency is required. There is significant potential for reducing consumption, especially in energy-intensive sectors such as construction, manufacturing, energy conversion and transport. Reducing energy consumption and eliminating energy wastage are among the main goals of the European Union.

Energy-efficient technologies in many instances are mature, although future technological developments are expected to enter the market. However, the efficient option is generally more expensive when compared to the conventional technology and is marketed as such. There is also a marked lack of skilled installers of new technologies and this needs to be urgently addressed. Any energy-efficient solutions must be robust enough to accommodate possible radical changes in the fuel supply and energy infrastructure. The range of stabilization levels assessed can be achieved by deployment of a portfolio of technologies that are currently available and those that are expected to be commercialized in coming decades and that improved energy efficiency will play a key role in task of economy development [Ürge-Vorsatz, 2009]. Security and solidarity are essential factors contributing to an efficient energy policy. The European Union intends to change its energy policy by putting the accent on these two values. The aim is to reduce energy consumption by almost 15% and energy imports by 26 % by 2020. In this perspective, the proposed plan, organised around five main points, should contribute to achieving these aims. It is hoped that by 2050 renewable energies will completely replace carbon-producing energies. European leaders committed themselves to reduce primary energy consumption by 20% compared to projections for 2020. Energy efficiency is the most cost-effective way of reducing energy consumption while maintaining an equivalent level of economic activity. Improving energy efficiency also addresses the key energy challenges of climate change, energy security and competitiveness. Energy efficiency is both the result of policy developments and the application of concrete measures. Technology development creates the basis and environmental legislation has contributed much, especially the Emission Trading Scheme and transport emissions policies. Taxation and other fiscal measures such as State aid and recent industry policy tools also provide strong incentives for markets to realise cost-effective energy savings. It is important to continue relying on these efficient instruments, especially in the current difficult economic situation. (1) the general policy framework and the actions taken under the European Energy

Efficiency Action Plan; (2) the National Energy Efficiency Action Plans based on the framework Directive

on Energy Services (2006). (3) the legal framework for the most important consumption sector - buildings - and

energy consuming products; (4) flanking policy instruments such as targeted financing, provision of information

and networks like the Covenant of Mayors and Sustainable Energy Europe; and

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(5) international collaboration on energy efficiency. Energy efficiency is a proven, cost-effective resource for the European

Community. It is one of the cheapest ways of cutting greenhouse gas emissions and contributing to sustainability and security of supply. It supports economic development and creates jobs, and it also reduces energy costs providing lower energy bills for households and businesses alike. The relevance of effective strategies to improve energy efficiency to the EU's integrated climate and energy policy cannot be overstated. Considerable improvements in energy efficiency have already been made but a large untapped potential still remains to be realised. For its part, the Commission will facilitate mutual support in the implementation of the action plans, and introduce a number of new initiatives, notably on eco-design, buildings and combined heat and power, aimed at strengthening the EU framework for energy efficiency in the various end-use sectors.

Renewable energy is energy generated from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are naturally replenished. Sufficient domestic renewable resources exist to allow renewable electricity to play a significant role in future electricity generation and thus help confront issues related to climate change, energy security, and the escalation of energy costs. Generation of electricity from renewable resources has increased substantially over the past 20 years.

Solar energy comes from the sun. It can also be made directly into electricity using photovoltaic (PV) cells. The best-known method utilises sunlight acting on photovoltaic cells to produce electricity. Flat plate versions of these can readily be mounted on buildings without any aesthetic intrusion or requiring special support structures. PV cells make electricity without moving, making noise, or polluting. We most often see these in calculators and watches. Solar energy is not available at night, and energy storage is an important issue because modern energy systems usually assume continuous availability of energy. More efficiency can be gained using concentrating solar PV (CPV), where some kind of parabolic mirror tracks the sun and increases the intensity of the solar radiation up to 1000-fold.

Solar power plants

Wind is used to generate electricity. Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, wind mills for mechanical power, wind pumps for pumping water or drainage, or sails to propel ships. The windmills built long ago had many blades, but today's wind turbines usually have just two or three blades that turn when the wind blows. These blades can be up to 25 m long. They have wind farms where large groups of wind turbines are connected to electric utility power lines and provide electricity to the

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customers. Large-scale wind farms are connected to the electric power transmission network; smaller facilities are used to provide electricity to isolated locations. Utility companies increasingly buy back surplus electricity produced by small domestic turbines. Wind energy as a power source is attractive as an alternative to fossil fuels, because it is plentiful, renewable, widely distributed, clean, and produces no greenhouse gas emissions. However, the construction of wind farms is not universally welcomed because of their visual impact and other effects on the environment.

Wind farms

Compared to the environmental effects of traditional energy sources, the environmental effects of wind power are relatively minor. Wind power consumes no fuel, and emits no air pollution, unlike fossil fuel power sources but there is dangerous for birds. Danger to birds and bats has been a concern in some locations. However, studies show that the number of birds killed by wind turbines is very low, compared to the number of those that die as a result of certain other ways of generating electricity and especially of the environmental impacts of using non-clean power sources. Finally, noise has also been an important disadvantage. With careful implanting of the wind turbines, along with use of noise reducing-modifications for the wind turbines however, these issues can be easily addressed.

Biomass energy comes from plants and trees. Wood is the largest source of biomass energy. In the biomass industry we also use corn, sugarcane wastes, and other farming byproducts to produce biomass energy. Biomass is produced by organic residues and wastes or by specifically growing crops for energy production. Biomass energy, or bioenergy, refers to all forms of renewable energy that are derived from plant materials produced by photosynthesis. Biomass energy can be derived as mentioned above from wood, agricultural crops and other organic residues. Wood is a substantial renewable resource that can be used as a fuel to generate electric power and useful thermal output. Wood for use as fuel comes from a wide variety of sources. Wood for fuel use is also derived from (1) private land clearing and silviculture and from (2) urban tree and landscape residues. A third major wood resource is (3) waste wood, which includes manufacturing and wood processing wastes, as well as construction and demolition debris [Borowski, 2008]. It can be used in three ways: burned to produce heat and electricity, changed to a gas-like fuel, or changed to a liquid fuel. This liquid fuel is very important for transportation because nearly one-third of our nation's energy is now used for transportation. Energy produced by biomass could someday supply much of the fuel for our cars,

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trucks, buses, airplanes, and trains. This is very important because nearly one-third of our nation's energy is now used for transportation. Biomass could offer near-term business advantages and more strategic, long-term value. The benefits obtained from biomass power generation, such as waste reduction, emissions offsets, and local economic growth, can enhance the technology's overall appeal to utilities. The future of biomass electricity generation depends also on biomass integrated gasification/gas turbine technology, which offers high energy conversion efficiencies and will be further developed to run on biomass produced fuels.

There are other sources of renewable energy including trash, water, and geothermal. One day much of the energy you use may come from renewable sources. As scientists find better ways to develop renewable energy, we may no longer have to depend upon fossil fuel energy.

Renewable energy plays an important role in the supply of energy. When renewable energy sources are used, the demand for fossil fuels is reduced. In the past, renewable energy has generally been more expensive to produce and use than fossil fuels. Renewable resources are often located in remote areas, and it is expensive to build power lines to the cities where the electricity they produce is needed. The use of renewable sources is also limited by the fact that they are not always available — cloudy days reduce solar power; calm days reduce wind power; and droughts reduce the water available for hydropower. The production and use of renewable fuels has grown more quickly in recent years as a result of higher prices for oil and natural gas.

The main key priorities of the renewable energy are mentioned below: • Dramatically reduce dependence on foreign oil, • Promote the use of diverse, domestic and sustainable energy resources, • Reduce carbon emissions from energy production and consumption, • Establish a domestic renewable energy industry.

Development strategy of electricity production from renewables is of a critical importance to economic growth in the XXI century, because there is a rapid growth of energy demand, in general, and electric energy in particular. EUROPEAN STEEPS IN THE SUSTAINABLE DEVELOPMENT

A dramatically increasing dependency on energy imports e.g. by 2030 more than 90% of EU oil and over 60% of EU gas will have to be covered by imports. The European Union took an unprecedented step in the fight towards energy independency and against climate change. It signed up to binding, EU-wide targets pledging to meet 20% of its energy needs from renewable sources such as biomass, hydro, wind and solar power by 2020. The EU Council has endorsed concrete and ambitious targets on greenhouse gas emissions, renewable energy and energy efficiency to be reached by the year 2020. The agreement also includes commitment to a 10% use of biofuels in transport. Alongside this undertaking, the European Heads of Government also made commitments to bring down greenhouse gas emissions by 20% and to improve energy efficiency by 20% [Renewable electricity-Make the switch, Project report No 4, EU 2008]. Energy efficiency is one of the key ways in which CO2 emission savings can be realized and he UE’s growing dependency on external energy suppliers can be reduced. The significant potential of renewable energy is discussed in several opinions that provide robust analysis of the social, economic, technological and environmental benefits of these energies. There is unprecedented interest in renewable energy, particularly solar and wind energy,

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which provide electricity without giving rise to any carbon dioxide emission. Harnessing these for electricity depends on the cost and efficiency of the technology, which is constantly improving, thus reducing costs per peak kilowatt. Table1. Gross Electricity Generation from Renewables in 2006 [GWh]

Source: EU energy and transport in figures, Statistical Pocketbook 2009, p.44.

Since the late 1990s renewable has begun an era of strong growth. The

amount of electricity produced from wind and biomass particular began to increase owing to advances in technology as well as favorable policies [Electricity from Renewable Resources, National Academy of Science, Washington 2010, p.18]. Over the first timeframe through 2020, wind, solar photovoltaics and concentrating solar power, conventional geothermal, and biomass technologies are technically ready for accelerated deployment. During this period, these Technologies could potentially contribute a much greater share of the electricity supply than they do today. There is a fundamental attractiveness about harnessing such forces in an age which is very conscious of the environmental effects of burning fossil fuels and sustainability is an ethical norm. So today the focus is on both adequacy of energy supply long-term and

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also the environmental implications of particular sources. In that regard the near certainty of costs being imposed on carbon dioxide emissions in developed countries at least has profoundly changed the economic outlook of clean energy sources. Most electricity demand is for continuous, reliable supply that has traditionally been provided by base-load electricity generation. Some is for shorter-term (eg peak-load) requirements on a broadly predictable basis. Renewable energy sources have a completely different set of environmental costs and benefits to fossil fuel or nuclear generating capacity. On the positive side they emit no carbon dioxide or other air pollutants (beyond some decay products from new hydro-electric reservoirs), but because they are harnessing relatively low-intensity energy, their 'footprint' - the area taken up by them - is necessarily much larger. In Europe, wind turbines have not endeared themselves to neighbors on aesthetic, noise or nature conservation grounds, and this has arrested their deployment in UK. At the same time, European non-fossil fuel obligations have led the establishment of major offshore wind forms and the prospect of more. However, much environmental impact can be reduced. Fixed solar collectors can double as noise barriers along highways, roof-tops are available already, and there are places where wind turbines would not obtrude unduly. As World Nuclear Association report mentioned [The New Economics of Nuclear Power, WNA Report, p.5]., today, given the urgent environmental imperative of achieving a global clean-energy revolution, public policy has sound and urgent justification for placing a sizeable premium on clean technologies. Such environmentally-driven incentives can come through carbon taxes, emissions trading, or subsidies for non-emitting generators of power. INNOVATIVE SOLUTIONS IN ENERGY SECTOR IN EUROPEAN UNION – SAME CASES

This topic covers issues related to energy generation, consumption energy and how the industry is addressing the challenge of energy efficiency with the innovative solutions. As governments seek ways of reducing their dependence on fossil fuels, researchers are investigating new sources of renewable energy. One way to use cultivated material - known as biomass - is to simply to burn it like coal, using the heat to generate electricity in conventional power stations. But this is not very efficient, and a better way is to turn the biomass into gas first, and then use it to drive a gas turbine generator. Biofuels in Italy from various kinds of crops.

The innovative project to produce bio-fuel from biomass is JOULE project created to develop a small electricity generator which runs on fuel made from various kinds of crops. The project was helped by Italian state subsidies for electricity generation from renewables The process chosen in this JOULE project is called pyrolysis, in which the biomass is heated to around 500°C. A limited amount of oxygen is allowed to enter the reactor to provide the heat to sustain the pyrolysis process. The biomass does not burn; instead, it produces bio-fuel vapours, which condense to a dark-brown, mobile liquid that can substitute for fuel oil. Pyrolysis has the advantage over gasification that bio-fuel has a much higher energy density. Moreover, it can be stored for long periods and easily pumped and transported. The gasification process takes place at a higher temperature and longer residence times, and involves the partial combustion of the fuel to obtain a fuel-gas whose

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combustible compounds are carbon monoxide, hydrogen, and a small fraction of very light hydrocarbons [ec.europa.eu]. The different sources of energy management system

The first CARE prototype - an integrated management system for different sources of energy - was installed in Crete few years ago and now will be tested the successor MORECARE. The CARE and MORECARE projects aim to take up this challenge. This issue is all the more urgent because new management of electricity distribution networks capable of taking account of the uncertain nature of some energy sources, such as the wind or the sun, is proving to be of particular value for isolated regions or islands. The system is sufficiently open to integrate other energy sources, such as solar thermal, photovoltaic and micro-hydraulic energy [ec.europa.eu].

The leading R&D institutes are working to develop a broad range of alternative energy technologies that are renewable and carbon-neutral - meaning the sources can be replenished and their use does not contribute to atmospheric global warming effects. These alternative technologies fall under the general categories of biomass fuel, electrochemical and magnetic technologies, geothermal energy, hydrogen fuel, solar, wind and nuclear energy. Researchers are also investigating an extensive variety of strategies for improving the efficiencies of the fossil fuel energy technologies in use today. The ultimate goal is to provide an overall energy portfolio that is viable, sustainable and environmentally supportable. REFERENCES 1. Borowski P., Development Strategy of Electricity Production from Biomass,

Antageng Conference, Antalya – Turkey, 2008. 2. Borowski P., Power Plants Management Under Tight Environmental

Requirements, ISTRO Conference, Izmir - Turkey 2009. 3. Electricity from Renewable Resources, National Academy of Science,

Washington 2010. 4. EU energy and transport in figures, Statistical Pocketbook 2009. 5. Renewable electricity-Make the switch, Project report No 4, EU 2008. 6. The New Economics of Nuclear Power, WNA Report. 7. Ürge-Vorsatz D., Metz B., Energy efficiency revisited: how far does it get us in

controlling climate change?, Energy Efficiency, 2/2009. 8. Clarke J.A., Johnstone C.M., Kelly N.J., Strachan P.A. and Tuohy P., The role of

built environment energy efficiency in a sustainable UK energy economy, Energy Policy, 12/2008, p.4605.

9. Ürge-Vorsatz D., B. Metz Energy efficiency revisited: how far does it get us in controlling climate change?, Energy Efficiency, 2/2009, p.287.

10. Renewable electricity-Make the switch, Project report No 4, EU 2008. 11. Electricity from Renewable Resources, National Academy of Science,

Washington 2010, p.18. 12. http://ec.europa.eu/research

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Chapter 2

THE CHANCES AND THREATS FOR DEVELOPMENT OF ECOLOGICAL

AGRICULTURE IN POLAND

Mateusz ĆWIKŁA, Anna PARKA INTRODUCTION

An agriculture is one of branches making national economy. On the one hand

it impacts on overall social and economic processes while on the other hand it’s an affected object in the whole economy. That explains the fact of constant development of this national sector observed from time immemorial. The agriculture shapes its closest surroundings and it shows a dependency on macro economic factors [Sobiecki 2003].

The beginning of ecological agriculture (depending on the country called also “organic” or “biological” agriculture) dates back to the 20’s of the XX century. The term “ecological agriculture” revealed relatively late, because in the early 80’s. The pioneer in ecological agriculture was philosopher and naturalist dr Rudolf Steiner. He depicted his original look at functioning of the nature during the course organized between 7-16 June 1924 in Kobierzyce near Wrocław. Among the audience of the above mentioned course were land owners, who later brought his reflections into reality. Having based on the same regulations Stanisław Karłowski, the duke and the senator of the 2nd Republic of Poland, was administering his own estate in Szelejewo next to Gostyń since 1930. The duke himself was especially involved in propagating the above regulations by publishing the instruction bulletins and trainings organized in his own estate. A dozen years after the II World War, in 1960 ing. Julian Osetek also implemented this method in his farm. The first training dedicated to ecological agriculture was organized in 1984 in Warsow. Officially the trainings dedicated to ecological agriculture started serving in 1989 [Sołtysiak 1993].

The first ecological farmer organization in Poland was the “Society of Food Producers using Ecological Methods EKOLAND” registered in 1989 and based in Przysiek n. Toruń. The first independent certifying unit AGRO BIO TEST was founded in 1996. The legal basis for ecological agriculture was established in 2001 when the Seym of the Republic of Poland passed the bill regarding ecological agriculture /16 March 2001/. The above mentioned bill made the conditions for correct functioning of ecological product market. The bill itself normalized the legal

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status of food producers using ecological farming methods, it gave the customers the guarantee of high quality products by having regulated the system of control and ecological agriculture product labeling. The next legal and financial changes referring to ecological agriculture were implemented as a consequences of affiliation of Poland with European Union [Michalska 2007].

The European Union imposes upon its member many requirements which incline the farmers towards changes in agricultural production methods as well as implementation of production standards in accordance with natural environment protection. Such policy results from e.g. environmental hazards occurring as a consequence of human activity, production, which does not meet the quality requirements, diseases and finally over – production as well as increasing level of unemployment. Taking into consideration the above mentioned aspects the sustainable development seems to be the best solution. The positive reaction is undoubtedly increasing social awareness regarding the inviolability of natural environment. The one should appreciate a mutual correlations between agricultural economy and closest surroundings reflected in suitable town and country planning.

The sustainable development is a town and country planning system which adopt its needs to the local demands. It combines the following [Wilk 2006]: • the social balance – it reflects the situation, which we are able to accept for

economic development, • economical balance – which aim is to maximize the achieved benefits, • environmental balance – it puts its emphasize on the public goods.

The ecological agriculture is the integral element of sustainable development, which refers to achieve ecological needs, especially to sustain stability of natural goods for future generation. Of course the ecological purposes are a priority so that they strictly limit the production methods only to those which are free of any harmful chemical agents namely biological methods of plant protection. It’s essential the ecological agriculture offers the food, which is produced using the methods that are favorable to natural environment. The fact is the demand for ecological products is still increasing. What’s more, ecological production development is the element of agricultural policy realized by countries affiliated with EU. Except offering the high quality products the ecological agriculture fulfills many other tasks. During ecological farming the high fertility of soils is sustained, the natural landscape is not devastated, the ground waters are protected, the gender protection within production area as well as closest surroundings are supported. Poland has a potential for ecological agriculture development due to high level manpower observed in the country, low level of environmental pollution, disintegrated agricultural structure, increasing interest and demand for ecological products and possibilities for export of these products. The above mentioned benefits inclines towards ecological agriculture development while on the other hand the one can observe a lot of barriers, both economic and social limitations affecting its development [Komorowska 2003]. THE PURPOSE OF THE STUDY AND METHODOLOGY

The ecological agriculture has been developing intensively for the last few

years as well as its role among EU members has been increasing. The economic crisis in the modern world is a common fact so in many countries people are searching for solutions allowing to protect both food and environment before contamination. It should be remembered that contamination is influenced both by industry and agriculture if any chemical fertilizers or toxic plant protective agents are

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used for farming. That should explain the tendency for eliminating potentially harmful chemical agents and replacing them with the organic methods of farming. Considering a dynamic development of the above mentioned sector the changes in agriculture in Poland should be also radical. No one can forget that the agriculture is one of the basic sector connected with human activity and it’s not only because of the fact that everybody has to nourish. Following the literature: our history, culture as well as social values has been connected with the agriculture from time immemorial [Szmidt 2008]. The essential purpose of this study was the analysis of ecological tendencies observed in Polish agriculture as well as to prove that the ecological agriculture development can make Poland more competitive among other countries in Europe. Having based on the available literature dedicated to ecological agriculture both chances and treats regarding the above mentioned economic activity were evaluated. The paper also depicts the organic and biological method as well as biodynamic method of farming. Having based on environmental researches and analysis the possibilities for ecological agriculture development in Poland were indicated. The paper presents thoroughly the aspects connected with: • both natural and agricultural environment protection as well as shaping the

natural and agricultural environment, • animal production, • technologies used for plant production, • biomass potential and possibilities of its creation. THE AGRICULTURE RESEARCH FINDINGS

After 1989 in Poland there have been few essential periods characterized by

different priorities in country and economy development. The first one, dated back to the 90’s of the last century, came to history as the time of political transformation. As regards food sector the transformation process started in the summer of 1989. In that time the prizes of agricultural and food products were released what resulted in market liberalization. The new legislative regulations eliminated the central instruments used for economy regulation and initiated the market solutions. In this period the economic balance in the agriculture was significantly changed. The application of market economy rules to disintegrated sector of agricultural farms showed negative consequences of lack of preparation for competition. That caused the financial inefficiency of huge number of agricultural farms and finally led to elimination of most of them from the market [Goraj 2005; Woś 1998] The next period refers to the times when Poland was involved in the European Union’s Accession Negotiations. The perspective of being a member of EU affected the huge expectations and interest among Polish agricultural producers. The farmers expected a general stabilization of agricultural markets, financial support resulting from the rules of Common Agricultural Policy given by EU as well as the increase in prizes of some agricultural products [Poczta, Siemiński 2002].

In a global scale the affiliation with EU was supposed to lead to the modernization of economy and legislative system, the acceleration of economy development as well as to the elimination of “development gap” between Poland and other European countries [Orłowski 2000]. The doubts, which then arose, were directly connected with the difficulties in adopting our country to EU requirements. The above problem especially referred to the agriculture as a consequence of lower

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production level, higher employment, more intensive structural disintegration as well as worse technical equipment [Gorzelak 1998]. The next period referring to our membership in the EU brought once again many changes resulted from the necessity for adoption to the requirements given by the Common Agricultural Policy and further changes in the trade introduced between EU members and other countries. The accession to EU meant gaining the access to the union founds, especially to unitary aerial payments connected with many instruments of agricultural market regulation or even structural funds. Undoubtedly that were the new functioning conditions regarding the food sector [Praca zbiorowa 2005]. Since Poland’s affiliation with EU up to 2009 the number of ecological producers increased over 4 times. The above mentioned increase was even without any significant peaks (figure 1). Presently in Poland there are about 17 500 ecological producers.

Figure 1. The number of ecological producers between 2004-2009

Private study based on the data provided by IJHARS (Agricultural and Food Trade Quality Inspection)

Expanding the above data according to the division into aerial groups the one can say that the highest percentage of agricultural farms up to 5 ha in area were observed in Poland between 2007-2008 (table 1). In 2008 these farms reached 36,5% of overall number of farms, what gave the score 8,5% higher comparing to the previous year. The significant percentage are the farms of 5-10 ha and 10-20 ha in area while the number of farms of more than 100 ha is very low.

Table 1. The number of agricultural farms in Poland between 2007-2008 gathered according to the division into areal groups

The percentage of agricultural farms according to the division into aerial groups in 2007 and 2008

The space

2007 2008 up to 5 ha 28,0 % 36,5 % 5-10 ha 25,0 % 23,5 % 10-20 ha 19,0 % 18,0 % 20-50 ha 15,0 % 13,0 % 50-100 ha 8,0 % 6,0 % more than 100 ha in space 5,0 % 3,0 %

(private study based on the data provided by IJHARS)

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The number of ecological farms determined independently for each province in 2008 is gathered in table 2.

The most of agricultural farms are located in the following provinces: małopolskie (2100), podkarpackie (1982), lubelskie (1566) and mazowieckie (1481) while the lowest number of farms was observed in opolskie (62), śląskie (176) or kujawsko-pomorskie (258). The highest discrepancy in the number of farms is observed in case of Małopolskie and Opolskie and it reaches 2 038. It’s also worth mentioning that only 58% of agricultural farms owns suitable certificate.

The transformation from traditional farming based on fertilizers and chemical agents used for plant protection to the ecological one takes about 2 years. Only after that time the producer may receive the official document confirming that his products are ecological. The certificate is granted by companies serving as a production supervisors, which are also called the certifying units. Presently there are 11 such units [PAP 2009]. At the end of 2009 in Poland there were registered 17 138 ecological, agricultural farms (figure 2). Table 2. The number of ecological farms in 2008 determined independently for each province

The province

The number of certified farms

The number of farms under transformation

Total number

Dolnośląskie 456 423 879 Kujawsko-pomorskie 158 100 258 Lubelskie 963 603 1566 Lubuskie 235 245 480 Łódzkie 190 124 314 Małopolskie 1318 782 2100 Mazowieckie 987 494 1481 Opolskie 35 27 62 Podkarpackie 1119 773 1892 Podlaskie 616 544 1160 Pomorskie 223 169 392 Śląskie 110 66 176 Świętokrzyskie 892 273 1165 Warmińsko-mazurskie 573 486 1059 Wielkopolskie 239 277 516 Zachodniopomorskie 571 825 1396 Poland 8 685 6 211 14 896

(private study based on the data provided by IJHARS)

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Figure 2. The number of ecological, agricultural farms - the situation on 31.XII. 2009

(private study based on the data provided by IJHARS)

In 2008 the total area destined for ecological arable lands increased by 9,5% (27 392,8 ha) comparing to 2007. The cultivated areas for which the certificates were obtained increased by 29,6% (40 841,4 ha) while the cultivated area under transformation decreased by 9,4% (14 191,6 ha). The highest increase in the total ecological arable lands was observed for 3 provinces, it means: opolskie (by 68,2%), małopolskie (by 56,4%) and łódzkie (by 35,6%). The highest increase in the cultivated areas for which the certificates were obtained, was observed in 2008 in provinces: śląskie (by 138,6%), łódzkie (by 84,4%) and lubelskie (by by 71,5%). As regards cultivation area under transformation the highest increase was observed in provinces: lubelskie (by 70,1%), opolskie (by 64,7%) and małopolskie (by 58,3%). Table 3 presents the areas reserved for ecological arable lands in each provinces in 2008.

The number of ecological food processing plants in each provinces is not high (table 4). In 2008 the decrease in their number in the provinces such as: mazowieckie (37), podlaskie (5) lubelskie (30) and zachodniopomorskie (12) was observed. The highest increase in their numbers was observed in case of provinces: dolnośląskie (11), małopolskie (17) and wielkopolskie (33).

The branches considered in ecological food processing are e.g.: both animal and plant fat production, oil production, drink production, animal feed production or fruit and vegetable processing. The percentage of the above mentioned branches in the overall ecological food processing shows figure 3.

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Table 3. The total area reserved for ecological arable lands in each province in 2008 The province The area with

certificate [ha] The area under transformation

Total number [ha]

Dolnośląskie 16035,3 12431,2 28466,5 Kujawsko-pomorskie 3665,3 2277,3 5942,5 Lubelskie 16986,9 9905,0 26891,8 Lubuskie 7927,9 10278,6 18206,5 Łódzkie 2801,8 2026,7 4828,5 Małopolskie 14839,7 7815,2 22654,9 Mazowieckie 16567,6 11174,7 27742,3 Opolskie 713,1 857,6 1570,7 Podkarpackie 19688,5 8982,0 28670,5 Podlaskie 10991,7 9418,8 20409,9 Pomorskie 5959,4 5406,6 11366,0 Śląskie 2301,3 1633,2 3934,4 Świętokrzyskie 7694,0 3146,7 10840,7 Warmińsko-mazurskie

16465,6 12362,3 28827,9

Wielkopolskie 9850,3 10566,3 20416,6 Zachodniopomorskie 26243,9 27906,8 54150,8 Polska 178 732,3 136 189,0 314 9321,2

(private study based on the data provided by IJHARS) Table 4. The number of ecological food processing plant in each provinces The province The number of

ecological food processing plants

in 2007 r. [%]

The number of ecological food

processing plants in 2008 r. [%]

The change in the number of ecological

food processing plants [%]

Dolnośląskie 6 11 83,0 Kujawsko-pomorskie

10 11 10,0

Lubelskie 34 30 -11,8 Lubuskie 5 6 20,0 Łódzkie 9 12 33,3 Małopolskie 9 17 88,9 Mazowieckie 42 37 -11,9 Opolskie 1 1 0,0 Podkarpackie 15 19 26,7 Podlaskie 7 5 -28,6 Pomorskie 8 10 25,0 Śląskie 15 13 13,3 Świętokrzyskie 7 10 42,8 Warmińsko-mazurskie

7 9 28,6

Wielkopolskie 18 33 83,3 Zachodniopomors-kie

13 12 -7,7

Poland 206 236 14,6 (private study based on the data provided by IJHAR)

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Figure 3. The percentage of branches in the ecological food processing in 2008

(private study based on the data provided by IJHARS) The ecological agriculture independently on the applied method of cultivation

provides the crop of highest quality and simultaneously it guarantees the natural environment protection. It is so called “elite agriculture” because it requires a good organization, larger amount of work and constant broadening the knowledge. The ecological farms should be not only the best school and the optimal way of farming but also should brought up with accordance to the spirit of cooperation between human and nature. They also should provide the moral satisfaction as well as they should develop the humanistic though. On the basis of these farms the farm tourism can be developed . Within the ecological agriculture the most common methods of farming are: • organic and biological method – it was initiated by Hans Muller – the social

activist from Switzerland acting in the 30’s. The theoretical basis were worded by German doctor and microbiologist Hans Peter Rusch in the 50’s. According to this method the purpose of the agricultural science is to achieve the optimal crop of highest quality without application any synthetic or chemical fertilizers for plant protection. It is possible to achieve provided the maximum fertility of soil is gained. Within the farms there’s a need for application of suitable plant succession matched with prolonged crop rotation. The suggestion is to cultivate the plants for a green fertilizer with papilionaceous plants as a main crop or a supplementary crop. The organic fertilizers produced within the farms, including a liquid manure and dung should be fully used as well as the correct cultivation should be implemented what means the elimination of ploughing and introducing the opening. In the organic and biological method it is allowable to use the natural minerals. The soil is protected against erosion by mulching, the insects and diseases are eliminated using biological agents while the weeds are eliminated using mechanical method.

• biodynamic method – its author is Rudolf Steiner, Austrian philosopher and naturalist. The biodynamic conception of nature focuses on the strict correlation between the Earth, Human and Outer Space as well as provides “the appearance of forces in the matter”. It says the human using specific preparations and activities may activate the forces leading to the increase in biological quality of agricultural products. Except these overall ecological rules saying about the increase in the soil quality, elimination of synthetic and

22

chemical agents for plant protection, the biodynamic method characterizes application of biodynamic preparations, it means application of silica in case of plants and six preparations for dynamization of compost. The second element distinguishing the above presented method is taking into the consideration the Moon rhythms influencing on the growth and development of plants [Budzyński 2002].

The inseparable part of many agricultural farms which are dedicated to ecological agriculture is an animal production. The animal production has to sustain the balance between agricultural production systems by satisfying the plant nutrient demand as well as enriching the organic matter of soil. In that way it may create and sustain the mutual correlation between animals, soil and plants. The farm animals must have the access to corrals and the number of animals referred to the single space unit must be limited in order to guarantee sustainable management of plant and animal production within a producing unit so that every possible contamination, especially soil and water (both surface and ground water) contamination could be minimized. In order to avoid the problems connected with the excessive pasturing and erosion within the pastures as well as to facilitate spreading of the liquid manure and to avoid any further negative impacts on environment the number of farm animals must strictly depend on the size of the available area [Sniady 2009].

The animal breeding guarantee sustaining the balance feed – fertilizer and makes a chain in the closed matter circulation within the farm. The animal stock results from the possibilities of self – supply in feed as well as plant nutrient demand. The balanced animal stock is one of the elementary ecological rules of production and it is limited by allowable nitrogen level, which can’t exceed 170 kg/ha in total amount of dung applied within the farm per year. If the dung surplus occurs then the farms where production is based on the ecological methods may cooperate with other farms and companies to sell the surplus. The farm animal must derive from producing units which meet the requirements determined by ecological methods. While choosing the farm animals the priority should be given to native breeds and varieties due to their possibilities of adoption to the local conditions, vitality as well as their resistance to diseases. As regards ecological agriculture a forced feeding is forbidden because as it is said the purpose of the feeding is to provide the production quality not its maximalization. The animals should be fed using feed produced by ecological methods within the farm. If it is not possible the one may use the feed supplied from another units or companies which respect the regulations on ecological production. The basis of feeding of young mammalia is a natural milk, for the best - the milk of the mother. The herbivores should receive green bulky feed, dried feed or ensilage providing at least 60% of daily dry matter contained in the feeding doze. As regards animal feeding it is forbidden to use medicaments, growth substances, antibiotics as well as any other preparations destined for growth or production stimulation. The feeds, the feed addictives or feed combinations must not be produced using any genetically modified organisms as well as products made of them. The disease prevention within ecological animal production is based on: • the selection of suitable breeds and varieties • application of farm practices suitable for gender requirements • providing the access to pastures and guaranteeing the regular activity in order

to strengthen the natural resistance of the animals; using the feeds of the high quality

• providing the optimal animal stock while avoiding the excessive concentration of the animals [Stachowicz, Pomykała 2008]

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The essence of fertilization in ecological agriculture is to sustain or to improve the fertility and biological activity of soils as well as to create the optimal conditions for plant growth. The basic fertilizers used within the ecological farms are: dung, compost, liquid manure or green fertilizers. Additionally within the ecological farms there are used some more supplementary fertilizers such as: • mineral fertilizers – grinded rocks such as basalt, bentonite, gypsum, kieserite,

dolomite, magnesium lime, carbohydrated lime, potash fertilizers: kainite, sulfate, potassium sulfate, phosphate rocks and arboreal ash

• organic fertilizers – bone meal, hoof meal, blood meal, feather meal eggshell meal, fish meal, wastes from one’s farm, bark and sawdust

• peat, sludge and deposits from natural water reservoirs The key role in ecological farms plays suitably planned crop rotation with

papilionaceous plants as a main crop that considers the application of supplementary crop as well as intercrop protecting the soil against corrosion. The suitably planned crop rotation fulfills the following tasks: • sustaining the correct amount of humus and soil fertility • preventing from excessive insect growth as well as disease development • preventing from uncontrolled weed growth

Within the ecological agriculture genetically established varieties characterized by wide resistance to diseases or insects, remaining competitive towards local forms of weeds and formed during many years of cultivation in the region are highly preferred. The essential requirement is to acquire a sowable or plant material reproduced within ecological farms or reproducing within one’s farm. It is forbidden to cultivate the plant genetically modified as well as to pickle the seeds and sowable material using synthetic agents. Amongst growth and development regulators only natural substances such as biodynamic preparations, humus extract or plant extract are acceptable. The weed elimination is directly based on mechanical cultivation techniques using harrows, ridging ploughs or hoes as well as biological herbicides, weed pulling or thermal weeding using special devices. The activities resulting in plant protection against insects and disease are: • shaping the farm environment and its surrounding to guarantee development

and protection of natural enemies of insects • cultivation of plant varieties which are resistant to disease and insects • suitable selection of seeding time and maintenance treatments • covering the cultivated plants by cloths during the insect invasion as well as

disease escalation • using the traps, barriers, ping or light emitters • cultivation of plant deterring or luring the insects • application of deterring or luring substances [Jończyk 2005].

The main purpose of the ecological agriculture is the ecological food production (phot. 1). This food is of high quality because raw materials used for their production came from the ecological farms located in the regions characterized by pure soils, air and water and they are not affected by any industry or municipal infrastructure. Within ecological farms the rigorous method of production are applied.

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Phot.1. Example of Polish shop with the ecological food

Source: M. Ćwikła

These methods are controlled by independent, professional certifying organizations. The ecological raw material processing is also under controlled technological regime. The ecological food quality is not evaluated on the basis of protein, sugar, vitamin and cellulose amount because presently used technologies enable to modify the food so it has nothing in common with any known, natural products. That’s way the highly modified food is also called the “plastic food”. As regards ecological agriculture the production process is controlled from its beginning until its end. The details on natural oils as well as controlled production processing are also given [Kaniewska 2008].

The increasing level of natural environment pollution connected with the excessive carbon dioxide emission is causing the increasing interest in renewable natural resources. The highest potential has a biomass which is converted to useful energy. A solid bio fuel is derived from a plant biomass using pyrolisis. The substrate for this process are waste wood taken e.g. from the forest, sawmill, furniture plant as well as straw, rape, grass and other arborescent or gramineous plant. A gaseous fuels are the products of gasification based on fermentation of sludge, manure as well as food processing waste. A liquid fuels are bioethanol, biodiesel or other liquid fuels derived from wood, methanol or bio oils.

The renewable natural resources is a cheap and human friendly energy. The application of renewable natural resources has a lot benefits for national economy including: • strategic one – the decrease in dependency on import of source energy • healthy one – reduction of diseases among society resulting from environmental

pollution • environmental one – reduction of green house effect, reduction of debris amount • agricultural one – reclamation of wasteland for agricultural production due to fuel

and energy sector needs, the use of surplus from agricultural production, reduction of unemployment in agricultural regions, the increase in capital stimulating the region development

In 2008 the national energetic balance shows that only 4% of original energy came from the renewable resources. The forecast is the renewable resources would reach 10% of that energy in 2010 [Fikiel 2008].

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CONCLUSION

The Polish agriculture has a lot of advantages especially if the one considers the possibilities for development of ecological way of farming in the regions, where natural condition as well as industrial level followed by a low environmental pollution favors ecological production. The traditional form of agriculture in Poland resulting from its disintegration as well as work reserves or low level of chemical agent application favors the ecological production and makes the Polish products more competitive in union market. Constantly increasing demand for ecological products, both in and out of EU, especially in USA makes a good prospect for the ecological food branch in Poland. So it is essential to implement the policy supporting its development as well as ecological education among society.

Of course the ecological agriculture development in Poland has both advantages and disadvantages. The advantages of ecological agriculture development are: • large resources and relatively low costs of work • the low environmental pollution • the majority of family farms of small and average area • low level of chemical agent application • founds coming from national and union budget • competitive prizes of polish ecological products in the union market

The disadvantages of ecological agriculture development are: • high costs of production • lack of trust towards ecological food producers • lack of developed distribution networks • disintegration of supply and demand • short expiration date of products • low level of marketing • poor development and agricultural policy strategy

The chances for ecological agriculture development are: • increasing number of customers characterized by highly developed ecological

preferences • increasing awareness of negative effects of agriculture intensification on life and

environment quality • creating the distribution and promotion system for ecological products within EU

markets • realization of agricultural and environmental programs • combining the ecological production with the farm tourism development

The treats for ecological agriculture development are: • low ecological awareness of customers and barrier for demand • small possibilities for supporting the ecological food branch due to founding

difficulties • fast increase in the number of ecological farms in the other EU members • small food processing plants have difficulties with meeting the sanitary and

veterinary requirements Considering the above mentioned aspects the most important factors for

ecological development in Poland are: • policy supporting both production and ecological food market • taking advantages resulting from the export chances

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• combining the ecological production with farm tourism • developing of units integrating disintegrated production as well as other units

acting in distribution including the groups of producers. REFERENCES 1. Budzyński O.: Dylematy ekologizacji gmin wiejskich, taktyka ekorozwoju gminy,

Wyd. Zielone Brygady, Kraków 2002. 2. Fikiel B.: Biomasa największym niekonwencjonalnym źródłem energii, Doradca,

MODR, Karniowice, XII/08. 2008. 3. Goraj L.: Ekonomiczno-rynkowe uwarunkowania przekształceń w sektorze

indywidualnych gospodarstw rolnych, Wieś i Rolnictwo nr 4 (129), 2005, 31-40. 4. Gorzelak E.: Rolnictwo polskie wobec uczestnictwa w Unii Europejskiej. Zesz.

Nauk. AR Kraków, Sesja Nauk., t. I, zesz.55: 1998, 13-24. 5. Jończyk K.: Płodozmiany w gospodarstwie ekologicznym, Centrum Doradztwa

Rolniczego w Brwinowie, Radom. 2005. 6. Michalska B.: Rolnictwo ekologiczne krzepnie, Gazeta Sołecka, Warszawa,

Nr. 11 (179), 2007, str. 42. 7. Kaniewska G.: Ekologicznie, czyli zdrowo, Gazeta Sołecka, Warszawa, Nr.10

(190), 2008, str. 44. 8. Komorowska D.: Perspektywy rozwoju rolnictwa ekologicznego w Polsce,

SGGW, Warszawa 2003. 9. Orłowski W.: Monitoring Integracji Europejskiej, Komitet Integracji

Europejskiej, 5. 2000. 10. Poczta W., Siemiński P., Sytuacja ekonomiczna rolnictwa polskiego w świetle

negocjacji akcesyjnych z Unią Europejską - próba prognozy, [w:] Zróżnicowanie regionalne gospodarki żywnościowej w Polsce w procesie integracji z Unią Europejska. AR Poznań, 2002. 347-381.

11. Praca zbiorowa, Stan polskiej gospodarki żywnościowej po przystąpieniu do Unii Europejskiej, Raport 1, IERiGŻ Warszawa 2005.

12. Sobiecki R., Integracja i globalizacja a rozwój rolnictwa polskiego, [w:] Dostosowywanie polskiego rynku rolnego do wymogów Unii Europejskiej, IERiGŻ, Warszawa, 2003, 27-38

13. Sołtysiak U.: Rolnictwo ekologiczne: od teorii do praktyki, Ekoland, Stiftung Leben & Umwelt. 1993.

14. Stachowicz T., Pomykała D.: Prowadzenie gospodarstw ekologicznych, Centrum Doradztwa Rolniczego w Brwinowie, Radom. 2008.

15. Szmidt K.: Rolnictwo ekologiczne w Polsce i krajach Unii Europejskiej, SERiA, Warszawa, t. X, zesz.1. 2008.

16. Śniady R.A.: Produkcja zwierzęca w ekologicznym gospodarstwie rolnym, Mat. Szkoleniowe Uniwersytetu Przyrodniczego, Wrocław. 2009

17. Wilk W.: Regionalne zróżnicowanie gospodarstw zrównoważonych w świetle danych rachunkowości rolnej, SGGW, Warszawa, Prace Naukowe. 2006. nr. 38

18. Woś A.: Ustrojowe podstawy transformacji sektora żywnościowego, [w:] Rolnictwo polskie w okresie transformacji systemowej (1989-1997), IERiGŻ, Warszawa, 1998. 3-15.

19. Gazetaprawna.pl, W Polsce rośnie liczba gospodarstw ekologicznych, PAP. 2009.

20. Inspekcja Jakości Handlowej Artykułów Rolno-Spożywczych (IJHARS), http://www.ijhar-s.gov.pl/

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Chapter 3

ENERGY AND MATERIAL FLOW MANAGEMENT (MFM) IN AGRICULTURE

Osman YALDIZ, Berk KUCUKKARA, Can ERTEKIN MATERIAL FLOW MANAGEMENT (MFM)

Material flow management (MFM) is called the logical use of the materials and energy in production.

MFM is an appropriate tool-kit to design new efficiency strategies needed to manage industrial and urban metabolism processes in a sustainable way. The goals are achieved by ecological and economical areas and by observing social aspects. In addition, MFM is the most important factor for circular economy and sustainable development.

The management of agricultural wastes in distribution of scarce resources is an important factor in the economics. The task of the management of material flow becomes relevant for agriculture with the beginnings of the industrial production. There are some developments in the operational material flow management in last years. But the term "material flow management" is still unknown for the farmers. Actually in practice, the tasks of material flow management in agricultural production are material economics and logistics, as well as environmental management.

Material flow management in agriculture is conventional structure of the supply and disposal economy principle. In the sense of the normative lastingness requirement on the organic portions of the material flow systems, a special meaning attain material flow management.

Efficient handling systems in agriculture require an exact knowledge of the genesis and logistics of materials, the potential and technical options for the optimization of material flow, and also the availability. This knowledge is available in the context of the refuse economy. Logistical, technical and financial parameters of our refuse economy systems are outstanding.

The classical refuse economy already represents a simple form of material flow systems in agriculture. The input materials in agricultural production are soil, fertilizer, seed, plant protection agent and fuel. The output materials in agricultural production are yield product and residual substances. The yield product can be sold or used but agricultural wastes can not be sold. It actually contains disposal and never used in production and is not valuable product for agricultural enterprises. Therefore the

28

classical waste management is not sustainable. Regional, ecological and social aspects are not evaluated in this perspective.

Today, a material flow management can be organized in farms or materials can be sold to another plant as an input material. Waste management in the agricultural sector developed fast in the worldwide. There were no any legal regulations in Germany until 1972 for refuse disposal [Heck and Bemmann, 2002]. Today there are multiplicities, adapted regulations in the refuse disposal. After these regulations, the residual substances are eliminated in all sectors, and also in agricultural sector, by related actors. An example for the material flow management in a farm is shown below (Fig. 1).

Figure 1: Material flow management in agriculture

Waste mountains were occurred because of waste composed after agricultural

production. Dirtiness as a result of usage fossil energy sources intensively in agricultural production started to threat people life’s in the world. The decreasement in raw material reserves moved to agenda of primarily scientists then entire people with developing communication tools and consciousness of civilian society.

The new agenda composed in the World were discussed in Earth Summit organized by United Nations on Environment and Development (UNCED) in 1992 in Rio de Janeiro and “sustainable development” principle were occurred first time in Rio declaration. This principle is defined as balancing the fulfillment of human needs with the protection of the natural environment so that these needs can be met not only in the present, but in the indefinite future. The production and life philosophy in the World were rearranged according to this term.

The scientists and civilian society establishments were conducting intensive studies on planning of source usage in production, waste management, developing nature sensitive systems, re-organization of life. These studies ascertained the

29

necessity of planning of material flows according to the new principles in all systems. In this scope, a new working area comes into agenda of the World as “Material Flow Management”.

The development of eco-efficient products, services and technologies boost societies’ capability to create closed material loops and activate renewable energy potentials. All countries must implement new energy and resource efficiency strategies to ensure a competitive and sustainable economy, a Circular Economy (Fig. 2).

Figure 2: Circular Economy with MFM approach [Çetinkaya,2006]

The agricultural productions were started to re-planning according to the

sustainable development with material flow management approach. The material flow management evaluates the material and energy usage as a whole and targets to decrease environmental effects to the lowest value without concession of production method, high efficiency, quality production and life principles.

In this management; Energy usage, waste and raw material management were re-planned according to the sustainability principle in this management process.

The following strategies were adopted as a result of conducted studies; Energy management strategy Energy saving Efficient use of energy Usage of renewable energy sources

Waste management strategy Decreasement of waste production Re-use Re-cycle Advantages of a Circular Economy with the MFM approach:

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• More profits through higher system efficiency, • Less ecological impact through new technologies and intelligent concepts, • Optimized utilisation of own potentials, and Enhancement of regional added

value.

The wastes composed after agricultural production and usage of agricultural products seems as an important problem. This problem is tried to be solved by steering the organic agricultural wastes composed as a result of intensive production to re-use in production.

The balance of life cycle based on reduce of wastes. The rupture of this chain is a result of environmental problems in these days. Mineral fertilizing, intensive chemical usage, insensible soil usage as long as many years, are continuing to be a big problem in some countries where environmental problems are not discussed.

The wastes composed after livestock production has also big share. The most common method is storage at unchecked conditions. Stored wastes on land cause CO2 and CH4 gas production. In addition to these gasses, composed anaerobe fermentation at the storage stage and nitrate cumulation are also other important environmental problems. Leaving agricultural wastes in produced areas is also one of the sources of greenhouse gases. The gases composed as a result of anaerobe fermentation releases directly to the atmosphere.

Biogas and compost are utilizable production technologies. The aim of biogas production both energy and fertilizer production. Only organic fertilizer productions mentioned in composting. But both of them named as waste and aimless destroyed or stored away are the re-evaluation applications of wastes. That is necessary to consider these technologies which can be used both storage or usage of agricultural wastes, increasement of farmers income and usage of the term “industry”.

By spreading of biogas production, wastes composed after agricultural production will became a raw material in industrial production. In addition, organic fertilizer composed after fermentation will be used as an input material in agricultural production. The farmers activating joined in this cycle will become a partner of this amenity.

Manure, plant and other wastes can be used in biogas production. In the biogas fermentation, organic fertilizer, electrical and thermal energy produced from organic wastes. This energy can be sold or used by farmers. Organic fertilizer can be used in agricultural production for livestock. The residual substances in the livestock production can also be used for gas production. That is a good example of material flow management in one of the agricultural enterprise.

New working areas are generated by material flow management perspective. Occupation companies can connect in the form of material flow management companies for economical and social goals.

The system of the occupation company can be substantially improved in combination with a material flow management strategy [Heck and Bemmann, 2002]. ENERGY PRODUCTION FROM AGRICULTURAL WASTES

Usage of local energy sources as well as agricultural residuals, steps apart from the discussed advantages of supply security to the environmental compatibility by CO2 neutral burns, so, that can be avoid long routes of transportation from the production to the final use. The utilization of agricultural residuals in agriculture has different advantages. The residuals are either burned irregularly or simply stored.

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Both methods cause a large environmental pollution. However, all of these residual substances contain energy. They can be used with different methods for energy production. These methods serve also procuration security, increase of economy in agricultural production and environmental compatibility. These energy-related political goals are shown in Table 1.

Power production from agricultural residual substances in an enterprise has following advantages. a) high energy efficiency b) optimum energy and waste management c) energy supply in own enterprise d) clean environment in farms

The farmers are actually energy users, they pay much more money for energy

and total production costs constitute large portions of energy costs. If the energy costs are reduced, the production costs could be degraded in the agricultural production. The decentralized one on local available resources developed power supply creates new jobs. The biogenous energy sources create five times more jobs than conventional fuels, like natural gas and oil. Use of the regenerative energies consists of local jobs within the range development, building, operating and maintenance. It concerns with its jobs all qualification levels [Heck and Bemmann, 2002]. Table 1 Political goals and strategy during the use of agricultural waste materials for the power production [Heck and Bemmann, 2002]* Procuration security Economy Environmental

compatibility

Strategies

� Strengthen and develop native resources

� Reduce import risks

� Use more economical and rational energy

� Provide technical security of power mains

� Create economical and efficient energy supply for industry and consumers

� Secure energy production standards

� Increase export potentials of energy producers

� Create energy producers from agricultural production

� Meet energy industry in agriculture

� Increase farmers income

� Replace polluting energy sources with environmental energy sources

� Usage energy in logical and economical

� Reduce environmental pollution by storage of agricultural and animal wastes

Added to the original table by author

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BIOMASS TECHNOLOGY

Biomass is one of the renewable energy source. Biomass is biological material derived from living or recently living organisms. For example wood, waste and alcohol fuels [Anonymous, 2007d] (Table 2). Table 2: Biomass Technology Chart [Anonymous, 2007d]

Technology Conversion Process Type

Major Biomass Feedstock

Energy or Fuel Produced

Direct Combustion

Thermochemical wood agricultural waste municipal solid waste residential fuels

heat steam electricity

Gasification Thermochemical wood agricultural waste municipal solid waste

low or medium-Btu producer gas

Pyrolysis Thermochemical wood agricultural waste municipal solid waste

synthetic fuel oil (biocrude) charcoal

Anaerobic Digestion

Biochemical (anaerobic)

animal manure agricultural waste landfills wastewater

medium Btu gas (methane)

Ethanol Production

Biochemical (anaerobic)

sugar or starch crops wood waste pulp sludge grass straw

ethanol

Biodiesel Production

Chemical rapeseed soy beans waste vegetable oil animal fats

biodiesel

Methanol Production

Thermochemical wood agricultural waste municipal solid waste

methanol

Added to the original table by author.

METHODS OF ENERGY PRODUCTION FROM AGRICULTURAL WASTES Biodiesel

Biodiesel is produced from biological sources (such as vegetable oils), which can be used in diesel-engine vehicles. It is thus distinguished from the vegetable oils or waste oils.

Biodiesel is biodegradable and non-toxic, and typically produces about 60% less net carbon dioxide emissions than petroleum-based diesel (Anonymous, 2007b). The farmers can produce the biodiesel for their requirements in small plants. So, they can have cheap and pollution free energy via biodiesel process. That is very important for the farmers to degrade production costs.

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Bioethanol

Bioethanol fuel is produced by sugar fermentation process, although it can also be manufactured by the chemical process of reacting ethylene with steam. The main sources of sugar required to produce ethanol come from fuel or energy crops. These crops are corn, maize and wheat crops, waste straw, willow and popular trees, sawdust, reed canary grass, cord grasses, jerusalem artichoke, myscanthus and sorghum plants etc (Table 3). Table 3: Biodiesel and ethanol production in European Union in 2004 (tons) [Anonymous, 2006c]

Country Biodiesel Ethanol Country Biodiesel Ethanol France 348 000 80 887 Denmark 70 000 Sweden 1 400 56 529 Netherlands 11 146 Germany 1 035 000 20 000 Italy 320 000 Finland 3 768 Greece 0 Poland 0 38 270 U.K. 9 000 Spain 13 000 202

354 Slovakia 15 000

Austria 57 000 Latwia 0 9 800 Czech Republic 60 000 TOTAL EU 1933

400 422 754

Anaerobic Digestion

Anaerobic digestion can help to dispose of all wastes and to control odor of livestock production. This is a logical method for disposal of waste management. That is why electrical and thermal energy and bio-fertilizer is produced. Nonetheless harmful microorganisms are eliminated and CO2 and methane emissions can be reduced by biogas production. So that the farmers should be motivated to use this technology.

As a fermenting substrate for bio-gasification only one organic waste is enough. They do not have to contain harmful materials. Beside liquid manure and bio waste, the other residual substances such as biowaste, grass cut, wastes from the vegetable production, intestine contents, fish wastes, liquid manure, wastes from the milk industry, energy plants (corn, potatoes, field beans, feeding carrots), wastes from the beverage industry and sewage sludge can be used in fermentation of biogas (Table 4). However, the following points should be considered; a) The origin of the materials is to be specified clearly, b) The quantities and qualities of the material should be known in planning stage, c) Temporal availability and prices of material, d) The waste category should be known before utilization, e) Special requirements at processing stage should be known, f) Characteristics (Specific gravity, dry substance content, organic dry substance

content, nutrient content, gas productivity) should also be known [Heck and Bemmann, 2002].

34

Table 4: Biogas production from different organic wastes [Kuhn, 1995] Material DM

(%) ODM (%)

Ntot.

(%) NH4-N

+

(% -Ntop) P2O5

(% KM) K2O

(% KM) Mg

(% KM) Biogas(l/kg.ODM)

Cattle manure

6-11 68-85 2,6 39-60 0,5-3,3 5,5-10 0.3-0,7

200-260

Pig manure 2,5-9,7

60-85 6-18 50-92 2-10 3-7,5 0,6-1,5

260-450

Chicken manure

10-29 75-77 2,3-6 69-70 2,3-6,2 1,2-3,5 0,4 200-400

Sheep manure

25-30 80 3 35 1,2-1,7 2,7-4,8 400-500

Horse manure

28 75 2,1 1 1,8 300-400

Grass silage

26-82 67-98 3,5-6,9 6,9-19,8 0.38-0.76 500

Grass 86-93 83-93 2,0-2,1 5,7-12,4 0,19-0,33

Clover 20 80 2,8 0,7 3 400-500

Cereal straw

85-90 85-89 0,5 0,2-0,4 11-2,3 300-600

Corn straw 86 72 1,2 0,5 1,7 600-700

Beet leaf 15-18 78-80 2,0-2,5 0,5-1,1 4,0-4,7 0,72 400-500

Potato leaf 25 79 1,5 0,5 2,9 500-600

Apple pulp 2-3,7 94-95 0,73 300 Potato pulp 12-15 90 5-13 0,9 6,4 330

Wheat pulp 3-5 96-98 6-9,9 3,6-6,0 0,4-0,7

Molasses 10,5 71,2 Grape pulp 40-50 80-95 1,5-3,0 0,8-1,7 3,4-5,4 0,15 Waste from malt industry

21-15 66-95 4,0-5,0 1,5 1,2 800

Waste from milk industry

4,3-6,5

80-92 0,7-1,5 20,3 0,8-1,8

Vegetable waste

5-20 76-90 3-5 0,8 1,1 400

Aromatic plants

53 55 2,3 1,2 1,1

Cacao glumes

95 91 2,5 1 2,8

Waste from oil plants

92 97 1,4 0,3 1,2

Waste of raps

88 93 5,6 2,5 1,6

35

Biowaste 40-75 30-70 0,5-2,7 7 0,2-0,8 0,3-0,8 200-600

Animal flour 8-12 2-5 0,3-0,5 Blood flour 90 80 12 0,6 1 0,6 Food wastes

9-37 74-98 0,6-5,0 1,5-22 0,3-1,5 0,3-1,2 0,04-0,18

500-700

DM: Dry matter; ODM: Organic dry matter Table 5: Electricity production from biogas in the European Union in 2004 and 2005 (in GWh) [Anonymous, 2007d] Country 2004 2005 Country 2004 2005 France 444,0 460,0 Netherlands 282,0 286,0

Sweden 61,6 53,4 Hungary 23,0 25,0

Germany 4414 5564,0 Italy 1170,3 1313,1

Finland 21,7 21,7 Greece 179,0 179,0

Poland 155,0 175,1 United Kingdom 4383 4690,0

Spain 824,7 879,4 Belgium 231,9 236,9

Austria 57,7 57,7 Slovenia 30,3 32,2

Portugal 14,6 34,4 Slovakia 2,0 2,0

Czech Republic

138,8 160,9 Ireland 101,0 122,0

Denmark 265,0 274,0 Luxembourg 20,3 27,1

TOTAL EU 12819,9 14593,9

Gasification

Gasification converts biomass into a combustible gas by thermo chemical process. Produced gas contains carbon monoxide, hydrogen, water vapor, carbon dioxide, tar vapor and ash particles. Gas quality depends on raw materials and process conditions.

Gasification process divided into two-stages. Heat vaporizes the volatile components of biomass in the absence of air at temperatures ranging from 450 to 600 °C in the first stage called pyrolysis. Vapor of pyrolysis process consists of carbon monoxide, hydrogen, methane, volatile tars, carbon dioxide and water. The residue, about 10 to 25% of the original fuel mass, is charcoal. The second stage of gasification is char conversion which occurs at temperatures of 700 to 1200 °C.

Produced gas contains 70 to 80% of the energy originally present in the biomass feedstock. The gas can be burned directly for space heating or drying or burned in a boiler to produce steam. The gas can be converted into methanol, a liquid fuel. Electric power can be produce by combining a gasifier with a gas turbine or fuel cell [Anonymous, 2007e].

36

REFERENCES 1. Anonymous, 2007,a. http://en.wikipedia.org/wiki/Material_flow_management 2. Anonymous, 2007,b. http://www.energy.eu/focus/biodiesel.php 3. Anonymous,2006,c.http://ec.europa.eu/environment/integration/research/newsa

ert/specialissue_en.htm 4. Anonymous,2007,d.http://www.oregon.gov/ENERGY/RENEW/Biomass/biogas.sht

ml 5. Anonymous, 2007,e. http://en.wikipedia.org/wiki/Gasification 6. Anonymous, 2007,d.http://www.oregon.gov/ENERGY/RENEW/Biomass

Home.shtml 7. Çetinkaya,H., Deutsche-Türkische Konferenz in Stoffstrommanagement,

Klimaschutz und Nachhaltige Entwicklung.6-7 October 2006.Antalya 8. Kuhn, E.: 1995. Kofermantaion, Arbeitspapier,219; Hrsg. KTBL, Darmstadt

Heck, P., Bemmann, U., 2002. Praxishandbuch. Stoffstrommanagement. 2002/2003. Fachverlag Deutscher Wirtschaftsdienst GmbH &CO.ISBN 3-87156-481-8

37

Chapter 4

ROLE OF WIND ENERGY IN AGRICULTURE

Grażyna Paulina WÓJCIK INTRODUCTION

In the light of depleting natural resources, rising fossil fuel prices and increasing ecological awareness, alternative energy sources, including most of all wind power, are becoming increasingly popular.

In comparison to other European countries particularly the ones whose use of renewable energy sources is advanced, such as Germany, Spain or Denmark, Poland is only beginning its wind power adventure. This energy source was practically not used in Poland at all before the 2000.

Large areas of the country characterised by favourable wind speed (from 5,5 to 7,0 m/s at the height of 50 metres) make Poland one of the most attractive wind farm locations in Europe.

Poland has also witnessed a substantial rise of interest of domestic and foreign companies in execution of wind power-related projects.

To fulfil the aims of Energy Packet 3x20 in the part relating to the share of Renewable Energy Sources (RES) Poland has to use more widely current results but also propose innovative development programs addressed to businessmen, the farmers, village dwellers and the users of energy.

The base of energy revolution in Europe is the project of EU strategy, announced in March 2007 r., which makes the renewable energy one of the most important development pillars of energy safety of EU, and simultaneously the main tool for the decrease of greenhouse gases emission. The United Kingdom already proposed the reduction of CO2 emission by 60% and Germanys by 80% till 2050.

The foundation of energy revolution in the world is the world explosion of innovative energy technologies.

Agriculture as an economy sector can benefit from the development of the agriculture power engineering, both in the short- and long-run.

Short-run development of agriculture power engineering assures the use of 2-3 million hectares of uncultivated land as well as fallows and wastelands. This is about 10 to 15% of agricultural lands in Poland.

In the long-run it creates the fundamental basis for durable profitability of agricultural production resulting in the possibility of widening the agricultural

38

production supply, both on: food and energy markets. Restructuring of the Polish agriculture leading to the mass development of economically-justified energy crop-growing can in future result in the use of 4 to 6 million hectares of arable soils and uncultivated lands for production of energy crops. Moreover it will generate additional 10 to 15 billion PLN (at current prices) of farmers’ revenues per year. In the long-run the development of energy agriculture can be used by Poland to actively participate in the process of closing the Common Agricultural Policy after 2013.

In the structure of the share of renewable energy on the final electric energy market 2020 r. it is assumed that green electric energy will be produced in Poland in 2020 r. from wind and water energy as well as from biomass waste but first of all it will produced in associated sources using bio-methane produced from energy crops and plants. The assumed structure is the following. • Electric energy from energy crops: 35 TWh, that is about 78%. • Electric energy from wind, water and biomass waste: 10 TWh, that is about 22%

Figure 1. Wind power station in rural areas

Source: The report "The Vision of development of wind energy in Poland to 2020” Polish Association of Wind Energy, Szczecin 2009.

USE OF WIND POWER STATIONS IN RURAL AREAS

In agricultural processes, the food processing, small business situated in rural areas as well as households the wind energy can be used: • to heat buildings and homes, • to warm water used in production and at home, • as a source of power for technological devices and other equipments: fens used

for drying crops and hay, devices used for preparation of feed, devices used to oxygen the manure etc.,

• as a source of power for water pumps, irrigation etc., • as a source of power for compressors to oxygen fish reservoirs and lakes,

The economic and ecological advantages resulting from construction and utilisation of wind power station:

39

• accumulated energy-consumption of energy production in wind power stations amounts to 3,5 - 4 MJ / 1kWh while in coal power stations 13,0MJ/1 kWh,

• 2/3 of annual electric energy production is generated in the period of five heating months this is November - March,

• there is no harmful pollution in the process of wind power stations energy production,

• unlimited supply of wind energy, • short period for construction and assembly, • the possibility of building wind power stations of 20 kVA at low costs without

hiring construction companies. WINDMILL PUMP UNITS

One of the effective solutions that can be applied in agriculture is a windmill pump unit that can be used for pumping water, re-cultivation of water reservoirs, particularly lakes, fish ponds as well as the stabilising reservoirs in sewage plants. Such devices should be applied where there is a biological in-equilibrium caused by organic, chemicals pollution, excessive alga and flora development. Decomposition of organic substances in water environment causes an increase in oxygen demand.

When the oxygen is used fauna and flora dies and begins to rot. Such a process creates an area with no oxygen and may be a serious threat to natural environment, human and animals’ health. These devices should also be applied in place where the demand for oxygen is relatively high (in water reservoirs) for ecological and technical reasons e.g. intensive fish farming. Lack of oxygen is one of basic factors limiting the increase in production efficiency: It causes: • decrease in fertility, impossible spawning, • limitation in taking, digestion and the utilization of food, • dying of water organisms making up for fish food , • limitation to fish activity, • mass deaths of fish in winter and summer period resulting in loss in production.

As the analysis of general wind conditions shows the whole area of Poland is suitable for installation of wind pump units. However the best wind conditions are in the northern and north-eastern regions where the needs for oxygening waters are the largest.

CURRENT DATA ABOUT WIND POWER ENGINEERING IN POLAND

Civilization development and utilisation of new lands by men influences our environment.

Wind farms can be placed in agricultural areas that can still be in use and produce income for their owner. Putting windmills does not change the purpose of the land, does not interfere in crops growing, does not require additional activities such as installation of soundproofing screens.

Looking at windmills on a horizon we see a balanced scenery where production of safe energy for millions of people succeeded and not ruined lives of millions creatures.

In the past when the wind energy was developing it was rather expensive technology, difficult to manage from the perspective of energy power system. Nowadays, legal acts have been changed, turbine units improved and modernized to assure constant delivery of energy at a required level and price.

40

Wind power stations do not emit over normalize noise or electromagnetic field. It is a fact that windmills emit waves but first of all acoustic waves that is sound. But the manufacturers of wind turbines have the whole row of guidelines and norms that precisely define the level of noise that a turbine can emit.

Windmills placed in accordance with the norms emit waves which in no way influence other devices in the vicinity. According to decree of the Minister of Environment of 14 June 2007 (Dz. U. of No. 120, pos. 826) the admissible level of noise during the day amounts to 50 - 60 dB and in the night 40dB - 45dB. It was measured that the noise in distance of 350 m from a turbine amounts to 40dB while a vacuum cleaner generates noise of 70dB.

It is worth underlining that the level of noise we encounter every day at home, work, that is in average room is c.a. 40-50dB. Modern wind turbines are so silent that you can stand just beneath and be able to talk without raising your voice. Though the first windmills made a horrible noise today’s windmills are hard to hear even from a small distance.

Figure 2. Map of Renewable Energy Sources in Poland

Source: The study the PSEW on basis of data the URE. The proportional distribution of power of RES technology in individual provinces of Poland. As of 31.12.2009

In the perspective of the next several years one should expect the

considerable dynamics of changes in agriculture restructuring process, modernization

41

of farms as well as their technical and social infrastructure. The difference of notions rural areas and agriculture will deepen. The trend connected with extension of housing estates on rural areas, in vicinities of municipal agglomerations cannot be stopped. It is a local authorities priority to assure adequate power infrastructure in those areas. The proper recognition of needs will help local authorities shape the development of regions and local energy policy. Forecasting of energy demand is a tool for planning and management of local power engineering [Chochowski, Krawiec 2008].

The development of renewable energy is an element of balanced development. The need for the development of production of renewable energy sources comes from the necessity to limit the emission of gases produced in the course of fuel combustion, depleting fossil fuel resources and increasing costs of their production. Moreover, Poland is obliged to protect the air by international agreements such as Framework United Nations Convention on climate changes and Kioto Protocol that makes Poland reduce greenhouse gases by 6% till 2008 - 2012 in relation to 1988.

The forecast of development of wind power energy envisages installation of power amounting to 13 GWe in 2020 r. – out of which 11 GWe in land wind farms, 1,5 GW in sea wind farms as well as 600 MW in small wind power stations.

Figure 3. The increase of power of wind power stations in Poland to 2020 r.

Source: The report "The Vision of development of wind energy in Poland to 2020” Polish Association of Wind Energy, Szczecin 2009.

The share of wind power stations in production of electric energy in Poland will

grow up quickly, to 17% in 2020 r. and almost 29% in 2030 r. It is forecasted that employment in wind energy sector will rise from over 2000

persons (the equivalent of full-time posts) in 2008 to 66 thousand in 2020.

42

Figure 4. The accumulated number of jobs in Polish

wind energy sector in 2010-2020 Source: The report "The Vision of development of wind energy in Poland to 2020” Polish Association

of Wind Energy, Szczecin 2009. NATURAL CONDITIONS FOR LOCATION OF WIND POWER STATIONS

The following natural conditions are the obstacles for the location of wind power stations: • marshy areas with peat and meadow flora on peat and mud-peat soils, with

unfavourable geo-technical conditions for placement of power stations; especially seaside muds, peatbog, river valleys;

• forests, • valuable flora assemblies other than forests and swamps, in particular seaside

and inland dunes, xeroterm grass areas on slopes of Vistula, heaths, • water reservoirs, • places important for birds - the attractive feeding grounds, routs of regular

flights, routs of regular flying to feeding grounds and resting places. COMMON AND LOCAL LEGAL ACTS ON NATURE AND LANDSCAPE PROTECTION VS. THE LOCATION OF WIND POWER STATIONS

The common law – the nature protection act - forbids the location of wind power stations in national parks and nature reserves. In other remaining areas of nature protection, and especially essential in regional scale landscape parks, it is allowed to place wind power stations unless the local legal acts do not allow or location of such stations will cause the devaluation the protected nature and

43

landscape. The landscape protection is common and is implemented though land development plans.

The local legal acts - the voivodship regulations relating to landscape parks, areas of protected landscape as well as the plans of protection of landscape parks exclude the location of wind power stations in landscape parks and in grounds of areas of protected landscape as well as these parts of parks surroundings where they would worsen the state of environment of park or scenery.

In local scale the essential limitation for the location of wind power station are little areas or small forms of protection of nature e.g. nature-landscape complexes, ecological uses, nature monuments, places of protected flora and fauna species – all should be excluded as the places for location of wind power stations for their ecological and landscape meaning.

All areas covered by the nature protection acts due to their value and the ecological meaning should be treated as excluded.

LANSCAPE CONDITIONS FOR LOCATION OF WIND POWER STATIONS

The following locations should be treated as inappropriate: foreground of panoramas, view axes and points with a view on historical monuments and valuable buildings, parks, especially dominant landscape, and also regions of planned cultural parks.

The areas of essential functional conflict are also areas of buildings (individual housing buildings, public utility buildings) as well as areas planned for development of dwelling districts, health resorts and recreation.

WIND ENERGY IN POLAND, EUROPE AND WORLDWIDE

In 2009 Financial Times (FDI Intelligence) named renewable energy as the most crisis-resistant. In 2008 40% more green field projects were executed worldwide as compared to the preceding year. The year 2008 was also decisive for the structure of new generating sources in Europe. For the first time ever the wind energy led the way followed by the gas and solar energy-based installations.

Figure 5. Cumulate installed capacity of wind turbines worldwide from 1996 to 2008

Source: European Wind Energy Association, Wind Energy Statistic, p. 1

44

Figure 6. Energy facilities installed in Europe in 2008 by energy carrier type

Source: European Wind Energy Association, Wind Energy Statistic, p. 1

In Germany, whose investment in wind power was the largest in Europe, the value of all construction facilities amounted to 23 903 MW at the end of 2008.

Since the wind power density conditions in Poland are similar, this demonstrates the unused potential of our country. Spain was ranked second in Europe with a cumulative installed capacity of 16 740 MW.

Recent years have witnessed a substantial growth of the wind farm installed capacity in Poland - its growth between 2000 and September 2009 was more than 166-fold. The dynamic development is also confirmed by the connection of facilities with the cumulative capacity of 206 MW between 2007 and 2008.

2000 2001 2002 2003 2004 2005 2006 2007 2008 IX 2009

4 18 59 60 65 84 153 276 482 666

Figure 7. Wind farm capacity installed in Poland (MW) Source: European Wind Energy Association, Wind Energy Statistic, p. 1.

The growing capacity of constructed facilities is reflected in the production of

electricity, which exceeded 790 GWh in 2008.

2004 2005 2006 2007 2008 I-V 2009

142,3 135,3 388,4 494,2 790,2 233,3

Figure 8. Electricity production by wind farms in Poland (GWh) Source: European Wind Energy Association, Wind Energy Statistic, p. 1.

45

According to Energy Regulatory Office data the installed capacity of the wind power section in Poland reached 666 MW (as of the end of September 2009). There are a total of 282 licensed sources in Poland. The main location for the wind energy stop of the Baltic seashore, a central Poland region with a prevalence of western provinces and the region of Carpathians.

BUSINESS LIMITATIONS AND PROSPECTS

Further major obstacles in the wind project development process are the complexity as well as procedural and legal obscurity of the proceedings in case of obtaining the environmental decision approving the execution of the investment form the point of view of environmental protection.

The issues pertaining to the assessment of the wind farm’s hazardous impact on natural environment, particularly in the context of protected bird species migration, are based, by necessity on the one hand on a subjective assessment by the representatives of scientific circles whose expert’s opinions are hardly ever absolutely decisive and are often contested in alternative expert’s opinions invoked for that purpose. On the other hand, decisions issued by environment conservators also leave a lot of be desired with regard to objectivity of criteria applied therein. As a result, negotiations conducted by investors in this respect are usually long and difficult.

The rendered decisions are often very restrictive and e.g. force investor’s to change the status of farm land and designate large areas to environmental purposes as an equivalent for the land approved to power investment.

Existence and significant expansion of protected areas which according to the Central Statistic Office constitute 32% of the total area of the country, together with the areas included I the NATURA 2000 programme, constitutes a significant barrier for the establishment of wind farms. A major portion of these areas is excluded form wind power development. This area will be excluded form wind power development. This area will be increasing annually, as currently works are conducted to expand the NATURA 2000 area by approximately 1,6 million ha.

The investors who have commenced the development of investments in the areas that will be covered by the programme in the future, may encounter formal and legal obstacles. Therefore the industry circles call for the soonest possible adoption of the ultimate list of the areas included in the NATURA 2000 programme, which would not be subsequently modified.

The existing condition of the transmission and distribution infrastructure does not make it possible to allow grid access for the volumes of energy produced from renewable sources that, in the years to come, would make it possible to meet the obligatory share of renewable energy in the total sold energy.

Since Poland is obligated to increase the participation of the energy produced form renewable sources to 15% in 2020, works related to the construction and modernisation of the existing power grids are of priority importance in this context.

It should be noted that no applicable legal regulations oblige the operators to modernise or expand the grids Hence. The issue is left at the discretion of managements of the respective operators, at the same time, it is not a secret that the priority investment goals for all large energy groups focus on reconstruction and construction of transmission / distribution infrastructure.

46

Figure 9. Most crucial obstacles for market growth according to investors

Source: The report "The Vision of development of wind energy in Poland to 2020” Polish Association of Wind Energy, Szczecin 2009

CONCLUSION

The wind energy is a dynamically developing sector of renewable energy in the world. The wind energy is one of the cheapest technological options for reduction of CO2 emission.

In the nearest future the wind power stations will be the cheapest renewable source of electric energy - the technology in which the costs of production of energy will be comparable with the costs of production of electric energy in nuclear power stations.

The growth of demand for electric energy from the side of industrial sector as well as the society, obligation of Poland resulting from membership in European Commonwealth, bigger restrictions in the area of environment protection, and too slow increase of new powers in conventional power engineering - this are only a few factors which cause the necessity of intensive development of renewable energy sources, including the wind energy, in Poland.

The most active local authorities wanting to use the possibilities created by unconventional energy plan construction of their own wind power stations or take part in private investments through provision of areas or support in getting funds from Environmental Funds or the European Union. The produced electric energy can be directly used in local industrial objects (sewage plants), reducing the costs of their functioning. The development of wind energy in local areas (counties) can also be correlated with local energy needs .

47

REFERENCES 1. Chochowski A., Krawiec F., Zarządzanie w energetyce, Koncepcje, zasoby,

strategie, struktury, procesy i technologie energetyki odnawialnej, Difin, Warszawa 2008

2. Rozporządzenie Rady Ministrów z dn. 24.09.2002 w sprawie określenia rodzajów przedsięwzięć mogących znacząco oddziaływać na środowisko oraz kryteriów związanych z kwalifikowaniem przedsięwzięć do sporządzenia raportu o oddziaływaniu na środowisko (Dz. U. Nr 179, poz. 1490),

3. Raport „Wizja rozwoju energetyki wiatrowej w Polsce do 2020 r.” Polskie Stowarzyszenie Energetyki Wiatrowej, Szczecin 2009.

4. Ustawa z 10 kwietnia 1997r Prawo Energetyczne (Dz. U. Nr 54, poz. 348 z późn. zm.)

5. [Ustawa z 27 marca 2003r o planowaniu i zagospodarowaniu przestrzennym (Dz. U. Nr 80, poz. 717)

48

Chapter 5

MODELING OF COMPLEX HIGHWAY AUTOMATED CONTROL SYSTEM

AS A TOOL FOR REDUCING THE FUEL CONSUMPTION AND EMISSION

IN HEAVY-DUTY TRUCKS

Myroslav OLISKEVYTCH INTRODUCING

One of possible means to reduce the volume of toxic exhaust gases of vehicles and environment pollution level is exploitation of them on such modes which are about to nominal. First of all it would enable trucks to save a motor-car fuel upon condition of just-in-time transport tasks fulfilled. However there are some obstacles for this purpose such as variables of traffic and road terms. That is why vehicles have to move with the mixed modes which include an acceleration, engine forced motion, free rolling, motion with permanent speed, braking. The part of accumulated by the power-plants energy disperse to the thermal kind of it. Engines here work by unsettled modes. That is accompanied with environment polluting by products of incomplete fuel combustion.

The other way to solve the mentioned problem is the use of hybrid power-plants which accumulate braking energy and outlay it under next accelerations. Unfortunately this way is impossible for highway trucks so far. The matter is not only that the powerful trucks hybrids are technically unrealized yet but also because the partial modes for hybrid options are also not favourable. REVIEW OF THE RECENT RESEARCHES

It is suggested the problem could be partially solved by use of information technologies to manage set of transport vehicles. Such control system is presently known as highway transport flows the objects of which are stationary travelling facilities. They are external to the sets of transport vehicles. All of them can be divided into four groups. The first deals the setting of priority lanes of motion which is time-variable or openings reserve lanes or prohibitions of lane change. The

49

technologies representing by these systems ground on velocity sensors or supervision cameras. Other words an average speed of vehicles is the object of control. But the infinity of place of location of sensors and actuators is the main deficiency of these systems. Moreover they are inadequate to the real traffic situations.

The second group unites methods and means of incoming or outcome traffic flows on the set area of highway. It is carried out by access or restriction on a highway switching on alternative direction of flows and so on. However these means do not give practical results so far as they follow the subjective signs of priorities grants and management.

The third group of the systems of „external” management deals with limitation of high rate of cars velocity of flows. If the vehicles is moving on different lanes of highway with different speeds it causes the necessity of manoeuvres which lead congestions and delays. If control system limits speed of „rapid” cars comparing them to speed of „slow” the traffic becomes homogeneous after speed and does not cause objective reasons for implementation of passing and changes of lane of motion. However, there is no certainly whether such method of management promote total delays due to the decline of the desired speeds of „fasts” cars. This failing is inherent to all three considered groups of the systems. Moreover they do not remove three known reasons of delays and congestions: (a) an unevenness of speeds of cars; (b) implementation of manoeuvres (often on reason (a)); (c) an acceleration and braking of separate cars [Григоров et al. 2004 ].

In order to remove human factors of vehicle driving out of harm's way manufacturers develops „internal” automatic control systems. In fact human as the most inertia subject in the system „driver-truck-road-environment” must be exempt from a necessity to execute instantaneous actions. This is the most popular opinion of developers of various navigation control and cruise and other intellectual systems [Финаев, Бутенков 2003]. However such systems have not completely positive influences on transport terms of highways. And if congestions appear on highways they lose the whole efficiency. Except for it the systems of „internal” control are too expensive so far. The system of VDC for example is implemented until now only with the cars of representative class.

The publications in which researchers deal with communicability of traffic participants appear more frequent now [Кожевников et al. 2007, Савватеев 2007]. This term means the property of at least couple of vehicles to establish an informative connection by on-board control systems. This property could be realized by use of collection and transmission devices which operate signals from the primary sensors of distances (radars), video, elements of radio contact of shorter-range. A quality and operative and also functional possibilities of such devices are growing up [Förster 1991]. However there are not evidences about efficiency of the complex using of different data devices in one automated system so far.

More of researchers consider the numeral measure of deviation of actual values of the controlled parameters from the optimum program of motion as a criterion of quality of operative control of transport flow on condition of power resource limitations [6]. Speed is the main parameter of the program of motion in highway indeed. Its constancy is the sign of minimum power charges of a transport process and successfully planned transport process. It is possible to determinate the numerical value of the desired speed for the fixed transport task of truck and for the known road conditions due to free motive and exactly not for maximal loading [Оліскевич 2004]. This value is realized in the real transport flows out of possible

50

tolerance because of bad knowledge and consequently through insolvency to make the adequate decisions of drivers very often. The less size of the informative field of driver the greater are total accelerations on the set route [Оліскевич 2004].

An acceleration arises up on highway in two cases. The first case can be described by such inequalities:

mindd > ,

211VVV

b≈< (1)

where d is a current distance between vehicles signed

1A and

2A ;

1AV is a

momentary speed of 1

A ; bV1

is desirable speed of 1

A ; 2

V − speed of leader 2

A . Inequalities (1) describe a situations when a car

1A follows

2A and takes the

current speed to desired but float time is limited for such maneuver on an distance

minddd −=∆ . Not having pay attention at simplicity and typically of such

situation it is difficult enough to predict it. In fact that it is necessary to know casual functions ( )xV

2 for unknown road terms certainly to check whether the

adequate value of acceleration is chosen according to safe braking distance:

( )( )t

dxxVV

j

II

b

∆

−

=

∫− min

0

11

1 (2)

In expression (2) a time interval t∆ has also a casual size. The second case of acceleration is described by correlations:

minII ≈ ,

211VVV

b>≤ (3)

due to a situation when

1A has a necessity to outdistance the

2A . Thus

1V must attain

some size .

1

оutV which guarantees the safe maneuver. There is need of check whether it is possible to attain speeds from the terms of dynamic properties of car and tires cohesion which on the set distance of the road is unknown.

Deceleration of car is a necessary program of motion element and some researchers assert that the greater intensity of motion of vehicle is the more thrifty is its mode [Григоров 2004]. However it operates in sense of the already executed program of motion. If necessary to pass to lower speed when the end of motion is not attained the intensive braking is an overrun of energy in the brake system. Therefore minimum deceleration is undesirable but as an element of motion it is needed. It is also possible at two cases. The first case of deceleration is described by correlations:

mindd ≥ ,

211VVV

b<≥ (4)

If the desired speed is attained there is not need or possibility to move with

greater speed obviously braking will be applied due to forces of external resistance of motion (free rolling).

Second case of braking is forced by correlation

mindd ≈ ,

211VVV

b<≥ (5)

51

Limitation on the interval of motion is attained here and there is not possibility for the passing.

Thus, after the analysis of four cases of acceleration/deceleration the algorithm of transport flow control can be developed depending on such functions as distance between cars ( )td ; desired program of motion ( )tV b

1; estimations of own

speed ( )tV1

. A goal function is an acceleration, or deceleration of car ( )tj1

is

( ) ( )tVVdFtji

b

ii,,,= , si K1= (6)

where F is a nonlinear, logically-extremely adaptive function.

METHOD OF RESEARCHES

On the basis of function (6) three models of automated control system of transport streams have been developed. It was foreseen that the system must develop the prognosis of own acceleration/deceleration and at the same time minimize him after expression (6) and also to follow to beforehand foreseen program of motion adapting it to the real transport conditions which was folded.

To get directly functions ( )tVi

and ( )td by any model with the sufficient measure of precision is not seemed to be possible. But one should take advantage of accessible of measured signals with the help of which it is possible to pass to the searched variables. The primary signals of highway traffic might often be measured with a significant error that is why report of and means of control of them are contradictory. That brings infinity in the process of the automated control. It deals for example to almost all of methods of measuring of speed and distance between mobile objects. Shortage of information for decision making can compensate such reports which having been collected and could create greater entropy not because of quantity but for their relationships [Оліскевич 2008]. For this goal researches were conducted with three stages: (I) a construction and analysis of functional model of motion of trucks and analysis of dependences of his parameters, (II) a choice of set of primary signals and synthesis of control algorithm, (III) an evaluation of credible error of automatic control and correction of initial models. Researches brought to three principle variants of the systems.

Variant first (figure 1) is On Board Automated Control System (OBACS) the object of management of which is a separate car A which has an external signals act about distances ( )td and which makes own signals in relation to frequency of rotation of every wheel ( )tW and in relation to the distributed load on every axe ( )tR

z.

Figure 1. A schema of On Board Automated Control System for a single truck: ( )tI −

external signal from obstacles (neighbor vehicles); ( )tRz

− matrix of signals of the tension metric system in relation to the partition of load on axes; ( )tW − matrix of

signals from the wheel sensors of frequency of rotation

52

On the ground of primary signals have been made estimations of: a) coefficient of tires coupling with the road ϕ in accordance with frequencies of

rotation of the wheels21

ww − ; b) total coefficient of rolling resistance ψ ; c) with (a) and (b) - estimations of current value and prognosis of own speed ( )tV .

An OBACS has additional option to correct itself if total delays attained the limit of uncontrollability. On the ground of functions ( )tV and ( )tV

b one has to make a

decision about a choice of next mode of motion. It is needed to mark that such system has considerable enough primary errors of measuring and evaluation of parameters

1∆ . In relation with errors

1∆ the mode chosen will not always calculate

real coefficients ψ and ϕ . It is discovered that OBACS even at the use the most modern facilities of telemetry results in the substantial changes of the primary desired program of motion of separate truck which is equipped by it. The greater intensity of traffic the more changes are tested by the desired program of motion.

The objects of control system of the second kind is a group of trucks each of them takes information synchronously. Set of signals is the same (see figure. 2). This is called United Automatic Control System (UASK).

Figure 2. Schema of United Automated Control System for a group of cars in a

highway transport flow

Additionally they exchange information about accordance of the chosen modes to the travelling circumstances and closeness of a transport flow. A group is created on the ground of availability and firmness of telemetric signals. The amount of vehicles which entered in this group depends on technical perfection of the system of transmission of signals and from the closeness of a transport flow and should be proven theoretically.

Third model of control system is offered on the basis of two previous with the difference that the objects of it are the group of vehicles which are exchanging reports and immobile objects of highways called landmarks which perceive and memorize and pass information to the next group of cars which are close enough to them (figure 3). It functions as Complex Dynamic Automated Control System (CDACS).

Figure 3. Schema of Complex Dynamic Automated Control System

L − landmarks (immobile traveling object)

sAAA K++

21UACS

( ) sitVi

,1, =

( )tVb

i

( )tdi

( )tJ

( )tRi

iW

53

Landmark L passes toward CDACS1 that information which is purchased them from the previous group of cars. On a highway obviously there can be such situations when an interval between transport vehicles is very large. That is why they are not exchanged signals. When the group of cars

siAA ++

+K

1 approaches to landmark

each of them can exchange with him saved information. Thus immobile road objects become the elements of CDACS by turns and a gap of information flows doesn’t exist any more.

To prove the high quality and ability of the automated systems which are based on the use of communication of signals between transport vehicles and landmarks of highway let as formulate and solve next task. Every truck from those group which co-operate in the informative field in obedience to the directives got at the moment

0t must be moved to the set distance S not before than up to moment

T . In other words right and counter-clockwise ends of trajectory of motion of car are fastened. Moreover having speed at the moment of time which is evened a transport vehicle must change it to ( )TV which was defined by CDACS. Thus within the period [ ]Tt ,0

program of motion of vehicle must be optimum after the criterion of a minimum of kinetic energy. This kind of energy is caused by motive force

kP which is added

conventionally to the centre of weight of trucks. Let write down proper functional

( ) ( ) .

0

dttVtPET

t

k∫ ⋅= (7)

Let write down the law of motion on the basis of balance of power

iwfk

PPPPdt

dVm ±−−= (8)

where

fP is the force of resistance of rolling,

wP is the force of resistance of blast,

iP

is the horizontal constituent of resultant forces of weight and normal reaction of support. All of forces which are in right part of equalization (8) are functions from the co-ordinate of the passed way or its derivates. Thus there are not the special complications in an order to recognize and approximate these functions through cars-predecessors or through the landmarks. Writing down these functions through the proper components and dividing expressed physical equalization of the state of car:

( ) ( ) ( )xkmgxkxkmgtuxmiwf

⋅⋅−−⋅−= δ2&&& (9)

where f

k is associated coefficient of rolling resistance which takes into account deformation of tires and road skidding; m is the weight of car,

wk is the coefficient of

air flow resistance which takes into account streamlining of vehicle area, δ is the coefficient of bringing inertia over of circulating the masses to the centre of weight of car;

ik is the coefficient of gravity resistance. In equalization (8) force

kP acts main

function of control and was sighted as ( )tu . Taking into account that the coefficient f

k and

ik come of similar nature let use a function:

( ) ( ) ( )( )xkxkg

xkifo

+=

1 (10)

54

calling it as associated road resistance function. So, equation (10) takes a new form: ( ) ( ) 2

xkxktuxwo&&& −−= (11)

Let us notice that in these researches the action of force of braking of truck is

missed consciously. Using of brake force is out of accordance of the goal of information system. Let utilize denotation:

xx =1

, xx &=2

, 2

xx &&& = , 21

xx =& (12)

Then equalization (12) will take a kind of system of state equation:

( ) ( )

=

−−=

21

2

22

xx

xktktuxwo

&

&

(13)

Such equations of the state enable to define the optimum function of vehicle

control ( )tu * which could take a minimum power charges written with the help of equalization (7). According to the theory of optimum processes [Понтрягин 2004] and principle of maximum of Pontryagin to get an optimum it is necessary to write the proper Hamilton function arrived at a maximum on an interval [ ]Tt ,

0. Let write down

this function changing the sign of counter-clockwise part of equalization (7) on opposite and taking into account equalization of the state (13):

( ) ( ) ( )( )

221

2

2120xxkxktuxtuH

owΨ+−−Ψ+⋅Ψ−= (14)

where ,

0Ψ

1Ψ ,

2Ψ are the multipliers of Lagrange for which will write down

conjugating differential equations:

( )( )

1

11

1

1x

xk

x

Ho

∂

Ψ∂=

∂

∂−=Ψ& (15)

2

21

0

2

22

2Ψ−

⋅⋅Ψ+⋅Ψ=

∂

∂−=Ψ

xku

x

Hw&

Boundary condition of the task is ( ) 0

1=

otx which are not considered as the

terms of transversally. These terms are absent here. Table of contents of the solving the system of equalizations (14) and (15) contains such function which would satisfy boundary terms exactly. Except for it on the possible area of solving are limited in relation to high possible speed of motion of transport vehicles is imposed that:

max2Vx ≤ (16)

Principle of maximum of Pontryagin says that to obtain maximum of functional

(14) it’s necessary to posses such continuous non-zero functions ( )ti

Ψ which meet conditions (15) and the value H as a function of admissible control meet a optimal

55

mean around continuous interval of [ ]Tt ;0

. After that let’s define the term of optimal control as

120ψ+Ψ−=

∂

∂x

u

H=0

Shifting that we could take ( )

201xt ⋅Ψ=Ψ (17)

We can’t take an optimal control algorithm from (17) as ( )tu is absent here evidently. It is impossible to consider the system of equations (15) after physical circumstances which are given to as by function ( )tk

o. Two possible cases has been

considered after this research. First assumes constko= that means the vehicle

moves constantly straightforward along non-crossing highway. It leads to 01=

Ψ

dt

d

and 11

C=Ψ where 1

C is constant. Taking into account (17) we have next result

.

21120constxCx =⇒=Ψ=Ψ− (18)

It means that main optimal condition is speed stability under constant road

resistance. This result is trivial one because it excludes the necessary of any control system use for exception speed stability control system.

The most general case can be modelled if ( ) ( )( )txAxk110

sin= [9]. In such a case we have the solution of first partial differential equation of (15) as

( )( )txAdt

d11

1cosΨ=

Ψ (19)

which is linear homogenous differential equation of fist order and can be solved by Leibniz formula. The solve is obtained under boundary condition that for 0

0=t →

01=x ,

02Vx = and for Tt = → Sx =

1,

TVx =

2. So,

( ) ( )

⋅−=Ψ ∫ ∫

S T

dtdxtxtxAC

0 0

1211cosexp

where 1

C is constant. Finally simplifying of solution gives

( )( )SVVAtCT

cosexp011⋅−−=Ψ (20)

Equation (20) shows that reliable root of solution of (15) must depend of

boundary condition of object of research movement. The solution of second partial differential equation of (15) was obtained by

Bernoulli method. The solve is

3

2

21

2

0222

Cxku

eCw

t++Ψ+⋅=Ψ

−

ψ (21)

were 2

C , 3

C are constants.

56

Algorithm ( )21

,xxu of vehicle control within CDACSi is too mach complicated to give it evidentially. It’s structure depends on such condition and limits: • length of distance of S which is constant according to available directive

information for drive; • time limit of [ ]T,0 for decision making and actuating;

• trajectory of vertical profile of road sighed by ( )1xk

o function for forecasting

period [ ]T,0 ;

• synchronization of ( )21

,xxu and ( )1xk

o.

To make a proper algorithm there was used the real-time-modelling application of MathLab Simulink. The model was designed on the ground of phase trajectory which consists two curves

( )

5241CxCx +=

−βα , (22)

7261

CxCx +−=β

where

⋅∈

TV

S;1α , [ ]5,0;0∈β are the rates of powers which depend of condition

defined above and which lead equation (17) to various kind from square parabola to cubic parabola. The point of regime change may lays inside the distance [ ]S,0 or out of it. RESULTS AND CONCLUSIONS

Solving process has turned foremost out that a degenerative case can exist as at 0

0=Ψ and 0

1=Ψ where the value of control function is indefinite. It means that at

certain terms which concern the set function ( )xko

and size of time interval [ ]Tt ,0

a function ( )tu can go out outside legitimate values (figure 4).

Figure 4. Fragment of 3-cycles highway traffic optimal route controlled by CDACS by

the moments of 30tt − depending on highway condition and traffic density

It is also found out that depending on frequency of information received at

TVV <

0 when vehicle must be accelerated to collect necessary speed at the minimum

57

charges of fuel the program of such acceleration can be presented as the partly discrete function (figure 4). Its shows that a vehicle moves with an acceleration during a part of such cycle which in obedience to a phase trajectory is described by a protuberant downwards parabola. Other part a car moves mainly under the action of forces of wind and rolling resistance. But such character of cycle is safe only when the cycle of acceleration was preceded him also. Possibility to move on the optimum program of motion is not given always.

The other result has led to conclusion that the model of optimal control process designed above deals with a problem of vehicle information supplying.

It is clear now that it is possible to solve out the problems of increase of density of transport flows on highway and reduce their pollution due to the reliable estimation of terms and environment of motion at the conditions of development and implementation a modern technologies of organization of control in a transport complex on the base of the use of new information and intellectual technologies. The obligatory condition of creation of such systems is proper communicability relationships between vehicles their self and travel immobile objects.

Evidentially in this time the existent systems of providing of motion of trucks have the substantial failing: slowly corrected database and inexact mechanism of evaluation of the state of the proper variant of the program of motion and algorithm of vehicle control. The problem of adequacy of evaluation of the state of the motor transport system deals the processes of their intellectualization and creation of the flexible computer-assisted mechatronic systems of motor transport complexes which are not only facilities of independent control transport vehicles but also necessary information (bases given) generator for acceptance of rational decisions in relation to organization of motion of trucks on highway. REFERENCES 1. Some ideas for freeway congestion mitigation with advanced technologies,

Traffic Eng. Control 43(10), 397-403 (2002). 2. Григоров М.А., Дащенко А.Ф., Усов А.В. Проблемы моделирования и

управления движением транспортных потоков в крупных городах. – Одесса: „Астропринт”, 2004. – 266с.

3. Förster H.J. “Der Fahrzeugfurer als Bindeglied Zwischen Reifen. Fahrwerk und Fahrbahn”, VDI Berichte, Nr. 916, 1991.

4. Кожевников В.И., Вытяжков Д.В., Толмачев В.В., Луговенко В.А., Гриценко А.А. Автоматизированная система управления дорожным движением/ - Вестник Северо-Кавказского государственного технического ун-та, серия «Естественнонаучная». № 1(6) 110. − 2007. - С.110-114.

5. Савватеев И. Г. Двунаправленные системы управления автомобилем в потоке с использованием средств коммуникабельности / Сборник научных трудов СевКавГТУ. Серия «Естественнонаучная». 2007. № 3. − Северо-Кавказский государственный технический университет. http://www.ncstu.ru

6. Гащук П.М. Оптимизация топливо-скоростных свойств автомобиля. – Львов: Вища шк. Из-во при Львов. ун-те, 1987. – 168 с.

7. Оліскевич М.С. Залежність швидкості і прискорення автомобіля в транспортному магістральному потоці від характеристик інформаційного поля/ Вісті Автомобільно-дорожнього інституту. 2008. №2(6) С.132-137.

8. Понтрягин Л.С. Принцип максимума в оптимальном управлении. − М.: Едиториал УРСС , 2004. − 64 с.

58

9. Гащук П.М. Оптимизация топливо-скоростных свойств автомобиля. – Львов: Вища шк. Из-во при Львов. ун-те, 1987. – 168 с.

10. Белицкий В.И., Зверев В.И., Морозов В.М. и др. Телеметрия. − Л.: МО СССР,1984. − 465 с.

11. Семенов В.В. Смена парадигмы в теории транспортных потоков. − Препр. Ин-та прикладной матем. им. М.В. Келдыша Рос. АН., − 2006. http://www.keldysh.ru/papers/2006/prep46/prep2006_46.html

12. Финаев В.И., Бутенков Д.С. ”Разработка интеллектуальных систем обгона и моделирование транспортных потоков”. в сб. трудов Научной сессии МИФИ, Москва, 2003, с. 164-165.

59

Chapter 6

SELECTIVE ASSESSMENT OF ENVIRONMENTAL SIDE OF TRAFFIC IN

LVOV

Jevgen FORNALCHYK, Roman KACHMAR

In many cities of the world transport, especially the motor one, has become the main origin of environmental pollution. Motor transport is an origin of toxic emission, as well as electromagnetic and thermal radiation, vibration, noise, and the products of deterioration of friction pairs and tires, used technological substances etc [Форнальчик 2007]. Increase of number of transport facilities (TF) with various level of deterioration and with a maintenance that is not always timely and qualitative, with defects of streets and roads system with its limited capacity have caused the increase of not only content of toxic components of gas used by TF motors [Форнальчик 2002], but also the increase of noise loading of city environment.

During last 10 years quantity of people in Lvov was increased in 1,3 times. Accordingly increased the quantity of private cars. It is 114,5 thousands registered units now, plus 25 thousands cars, which are daily arrived to towns. In accordance to level of saturation of the car’s market (157 units per 1 thousand people) town is in the category of big towns. Transport mobility of population is still increased and caused the growth of traffic density. For example, total density, including 2 directions, of one of the main roads of Lvov – Stryjska str. – was increased in 2,06 times.

At the same time unsatisfactory coordination system of signal (traffic) lights regulation leads to car’s queue before signal controlled intersection more than 50 m. Well known is fact that reduction of time of car’s stoppage will reduce not only transport expenses, even levels of air pollution by exhaust gases (so far as engine work on idle motion is characterized by not full fuel combustion) and transport noise.

Toxicity level of gas used by car motors depends on type of the motor and traffic conditions, fuel quality [3]. During move at a middle speed and loading while combustion of 1 kg of petrol 300-350g of used gas (UG) are to be dispersed to the atmosphere, including 225g of carbon monoxide, 55g of nitric oxide, 20g of hydrocarbons, 1,5-2,02 g of sulfur oxide, 0,8-1,0g of aldehyde, 1-1,5g of soot and others. While combustion of 1 kg of diesel 80-100g of UG are to be dispersed, including 20-30g of carbon monoxide, 20-40g of nitric oxide, 4-10g of hydrocarbons, 10-30g of sulfur oxide, 0,8-1,0g of aldehyde, 3-5g of soot and others. Besides there are also known emission limit value of main toxic components in roadside air in

60

population centers of Ukraine (one-off and average daily one in mg/m3): [QNO]=0,6 and 0,06; [QСO]=5,0 and 3,0; [QSO2]=0,5 and 0,05 [4].

Alarm levels of traffic noise on main streets are limited only by sanitary requirements: 55 dB for building territory (yards, internal passages etc.), 40 dB in housing in the daytime and 30 dB in the night time.

Studying of gas contamination and noise pollution of streets is covered in many investigations, intended for reasoning of their alarm levels, as well as for decrease of their actual values. Such investigations are headed by famous scientists: prof. Hutarevych Y.F., Filipov A.Z., Rudzins`kyj V.V. and others. However, there are still non-completely investigated so-called “bottlenecks” concerning ecological compatibility of traffic flows in certain places of streets system, especially in regions with intense crossroads.

According to our preliminary investigations maximal levels of traffic noise and gas pollution of the air are being observed exactly on the mostly loaded crossroads. Because of this we have made the program of further investigation of ecological compatibility of traffic flows more exact for such crossroads in Lvov.

The noise meter VSV 003 was used while investigation of noise pollution. According to standards traffic noise estimate methodic provides its implementation only for roads 50 m away from crossroads and stops of regular transport facilities. However the most intensive background noise arises exactly on crossroads. Therefore audio measurement on a crossroad was conducted taking into consideration the fact, that measuring microphone was located 7,5 m away from traffic strip of the first traffic line and at a height of 1,5 m. The microphone was turned to the side of traffic flow towards the center of the crossroad. Simultaneous fixation of movement intensity on the crossroad and the move of sound level meter`s pointer were fulfilled with a help of a camera working in video-regime.

Date, time, air temperature, type and state of the road carpet at the moment of measurements were fixed and recorded to the protocol. Determined duration of one measurement was 6 minutes that provides the accuracy within 1dB according to preliminary data. Every 3 seconds real and combined movement intensity were estimated taking into consideration coefficients of transport facilities types combination and value of maximal noise level within this period.

According to obtained experimental data we have defined mathematical expectation, built histograms and ranges of noise levels values distribution for transport facilities on certain crossroad dependently on a day of a week and time of a day.

The investigation of transport noise level was carried out on the crossroad with high-intensive movement in Pryvokzal`na district during September-November of 2009. The crossroad is specific because it is situated in close proximity to living zone and educational institutions. Its scheme with cross-flows combined intensity diagrams and direction of their further movement are represented on the Figure 1.

61

Figure 1. The scheme of the crossroad in Pryvokzal`na district with cross-flows combined intensity diagrams and direction of their further movement (time of

measurement - 1210, 8th of October 2009)

It is determined that the highest combined intensity of transport flow is being observed in direction D and from one-way direction C (1470 and 870 cars per hour, respectively). At that, the street of A direction that has a cross of tram flows and rails going over the road carpet, makes drivers of transport facilities to decrease their speed and then to speed up intensively, that causes increase of noise level from suspension elements and motors. Noise pollution levels distribution histogram (Picture 2) for this crossroad is built on the basis of the analysis of these levels. The picture shows, that the dispersion of noise pollution values is rather wide – from 70,5 to 76,0 dB, mathematical expectation 72,49 dB.

At the same time there are peak values of traffic noise level, caused by defective transport facilities (mainly public ones) and by unreasonable use of horns. Non-stop transport flows of all directions cause permanent minimal value of background noise on the level of 70,5 dB, that exceeds marginal permissible value by 41%.

During the same period of 2009 the selection investigations of hazardous substances content in atmosphere air of Lvov were conducted together with employees of Atmosphere Air Pollution Observation Laboratory of Lvov Regional Hydrometeorological Center. The investigations were conducted on 4 permanent posts with roadside air samples selection frequency 4 times per day 6 days per week. The content of six following polluting components was defined: dust, sulfur dioxide, carbon oxide, nitrogen oxide, anhydrous hydrogen fluoride and formaldehydes.

62

Figure 2. Transport flow noise level distribution on the crossroad in Pryvokzal`na

district [dB]

Determination of toxic substances concentration is to be conducted by laboratory method directly in the observation post. Sampling was carried out by method of aspiration of certain portion of atmosphere air through an absorbing device filled with liquid or solid sorbent for collection of toxic substances, or through an aerosol filter that keeps toxic components content in the air. Type of absorbing an device or a filter was determined dependently on the type of polluting component. One-time regime of air sampling was used. For one-time sampling (during 20-30 minutes) electrical respirator EA-2 was used.

The investigation of roadside air pollution was carried out in September of 2009 at 7:00, 13:00, 19:00 and 1:00 near upper part of Zelena street (not far from Syhiv underpass). A camera for fixation of transport flows intensity was installed thus to see movement of transport facilities in all directions. At the same time all contaminative components in the air were determined by laboratory employees.

Accordingly to monitoring results the value of maximum one-time and monthly average concentration of air pollution in Lvov (for September 2009) was received and compared with same period of year 2008. (Table 1)

The intensity of transport flows and their content were determined for all directions in every streets cut of the crossroad (Figure 3).

Obtained results of intensities and air pollutions were fixed in appropriate protocols. On the basis of these results we have built mathematical models of a response between level of investigated contaminative components and combined intensity of transport flows and time of day.

63

Table 1. Maximum one-time and monthly average concentration of air pollution in Lvov (for September 2009 compared to September 2008)

Concentration of air pollution Maximal one-time Monthly average

Pollute substance [mg/m3]

Se

pte

mb

er

20

08

Se

pte

mb

er

20

09

Ma

xim

um

pe

rmis

sib

le

09

.20

08

09

.20

09

Ma

xim

um

pe

rmis

sib

le

Dust 0,3 0,3 0,5 0,17 0,18 0,15 sulfur dioxide 0,092 0,086 0,5 0,045 0,034 0,05 carbon oxide, 6 7 5,0 2,35 2,79 3,0 nitrogen oxide 0,09 0,1 0,45 0,05 0,046 0,04 anhydrous hydrogen fluoride

0,007 0,004 0,02 0,001 0,001 0,005

formaldehydes 0,015 0,011 0,006 0,004

Figure 3. The scheme of the crossroad of the streets Zelena and Syhivs`ka with cross-flows combined intensity diagrams and direction of their further movement

(time of measurement – 1300, 19th of September 2009)

For example, change of carbon oxide concentration QСO dependently on combined intensity of transport flow І and time of day Т on this crossroad is shown on the Figure 4.

64

Figure 4. Average monthly (September) change of carbon oxide concentration

dependently on the combined intensity of transport flow and time of a day on the crossroad of the streets Zelena and Syhivs`ka

Analytically this relation is to be described by such equation (mg/m3) :

QCO =-5,9678+0,4076Т+0,0092І-0,0147·Т

2-0,0004·Т·І-1,9941·10

-6·І

2

Enhanced points on the picture show maximal one-time concentrations of

carbon oxide (for І=2525 cars per hour – 1900) QCO =5,0-6,0 mg/m3. Maximum permissible one-time concentrations in roadside air [QСO]=5,0 mg/m3. Approximately the same exceeds of permitted concentrations are being observed during spring-summer months.

Dependence of concentration of dust, nitrogen oxide, sulfur dioxide (Figure 5), anhydrous hydrogen fluoride and formaldehydes on combined intensity of transport flow and time of a day on the crossroad are also determined:

Qdust=-0,1366+0,035·Т+0,0003·І-0,0039·Т2-4,8662·10

-6·Т·І-6,3027·10

-8·І

2;

QSO2 =-0,0013+0,0013·Т+1,3406·10-5

·І-0,0003 Т2+1,3476·10

-6·Т·І+

+2,8253·10-10

·І2;

QNO2 =0,016-0,0012·Т -5,82·10-7

·І-0,0001 Т2+2,07·10

-6·Т·І +5,784·10

-9·І

2;

QHF=0,0009+8,3744·10-5

·Т-4,9554·10-9

·І-7,5965·10-6

·Т2-

-5,6895·10-6

·Т·І+1,9783·10-10

·І2;

Qform=0,003-8,817·10-5

·Т -1,8491·10-6

·І +1,1911·10-5

·Т2+3,5304·10

-8·Т·І+

+1,0278·10-9

·І2.

65

Figure 5. Average monthly (September) change of sulfur dioxide concentration

dependently on the combined intensity of transport flow and time of a day on the crossroad of the streets Zelena and Syhivs`ka

On the basis of fulfilled investigations it is possible to state following:

• Toxic components concentration level in city air exceeds marginal permissible values of concentration while hours of the most transport loading of streets and roads system;

• Concentration level of controlled toxic components in roadside air and noise level are conditioned by the intensity and the structure of transport flows, which by turn are related to time of day;

• Transport noise level on crossroads is higher than permitted sanitary standards by 1,4 times;

• Noise loading increases dramatically when electrical transport passes by, trams as well as trolleybuses;

• While speed of movement increases, noise of cars tires predominates, while acceleration regime – motor noise predominates;

• In acceleration regimes significant noise level is produced by cars with diesel motors with high capacity, especially public transport facilities.

Coordination of empirical distributions of noise and toxic contamination of urban-industrial environment with respective theoretical laws of random numbers distribution will enable formation of complex mathematical models those will help to forecast and to manage ecological compatibility of transport flows.

66

REFERENCES 1. Форнальчик Є.Ю., Качмар Р.Я. Характеристика техніко-технологічних

чинників забруднення природного довкілля //Матеріали міжнародного науково-практичного форуму “Екологічні, економічні та технологічні аспекти використання земельних ресурсів” 19-21 вересня 2007. – Львів: ЛДАУ, 2007. – С. 360-365

2. Форнальчик Є.Ю., Качмар Р.Я., Преснер Б.М., Гулай В.І. Вибірковий аналіз викидів оксиду вуглецю з відпрацьованими газами автомобілів//Автошляховик України. - 2002. - №2. - С. 16-19

3. Fornalchyk J., Kachmar R. Impact of formation and faction structures of gasolines on toxicity of exit gass of automobiles of general purpose // Problemy recyklingu: II Międzynarodowa Konferencja Naukowo-Techniczna. – Rogόw (Poland). - 2002. – P. 45-50

4. Hutarevych Y.F., Zerkalov D.V., Hovorun A.G., Korpach A.O., Merzhyjevs`ka L.P. Ecology of motor transport: Manual – K.: Osnova, 2002. – 312 p

67

Chapter 7

ENERGY ASSESSMENT OF DRIVING FORCE GENERATION

ON SELECTED TURF GRASSLAND

Włodzimierz BIAŁCZYK, Anna CUDZIK, Jarosław CZARNECKI, Marek BRENNENSTHUL, Katarzyna JAMROŻY INTRODUCTION

One of the major economic and environmental problems facing modern

agricultural technology and forestry is the reduction of soil degradation and energy loss, or minimizing the adverse effects on soil associated with using mechanical machines. Some negative changes in soil substrates, not only in agriculture but also in forests, are excessive compaction and horizontal deformation generated by shear forces from driven wheels greater than the turf stress limits [Antille et al. 2008, Botta et al. 2002, Li et al. 2007]. This problem is of particular importance in relation to permanent grassland soils, where the wheels not only affect roots but also the parts of grasses and perennials aboveground. The size of the problem is connected to the significant share of the total grassland areas in land used for agriculture. In Poland, grasslands cover about 4 million hectares, which represents 13% of the country and nearly 20% of land used for agriculture. Over the 26 European countries, these areas cover about 57 million hectares, or 36% of agricultural land [Dove 2009].

Permanent grasslands may be used for cutting, grazing or cutting-grazing. The latter use of permanent pasture is the most usual; the first crop is used for hay and then grassland is used for intensive grazing of livestock. In this use of grasslands, turf is not only intensely compacted/pressed by machinery wheels, but by animal hooves. Therefore, cutting-grazing exposes land to physical degradation, potentially leading to a change in the botanical composition of sward, as grasses included in the mixtures react in different ways to compaction.

Studies on the compaction of permanent grassland soils are conducted in many research centers, including Poland. Unfortunately, results obtained are often contradictory. Some researchers suggest such adverse effects of compaction on the yield of crops [Blaszkiewicz et al. 2003, Garcia et al. 2004], while others show positive effects on the yield of crops [Douglas 1997]. Additionally, in literature there are no analyses of changes in traction properties in relation to the compaction of turf.

68

Based on previous studies, it can be concluded that a change in habitat conditions resulting from different levels of wear (compaction) alters traction properties and driving forces. Previous papers have mainly dealt with the identification of processes generating driving forces by tyres on turf soils; the issue of losses accompanying the driving forces has usually been omitted. Therefore, it seems reasonable to study the process of the generation of driving forces on permanent grasslands, and also characterize this process in terms of energy, i.e. show what proportion of energy is irretrievably lost. Such a study should also have a utilitarian value, to answer what actions should be taken to minimize the losses. THE AIM, METHOD, MATERIAL AND CONDITIONS OF THE RESEARCH The main objective of this study was to show how the use of turf affects the generation of traction forces for a selected drive tyre with an AN tread. Detailed analysis included: 1. The plot of the forces and traction efficiency determined in the function of the

changes in the skid of the wheel generated by a tyre with and without anti-skid chains.

2. Maximum forces and traction efficiency for the established levels of turf wear and various vertical loads of the examined tyres (with and without anti-skid chains)

The study should give hints on how to limit losses associated with the generation of driving forces, which is crucial for the minimization of grassland degradation. The results should also indicate if there is any optimal vertical load for the examined tyres at which maximum traction efficiency is obtained (at the studied levels of use), and if the anti-skid chains may efficiently reduce energy losses connected with the generation of driving forces on the examined grassland.

The study was conducted at an experimental plot located between the shafts of the Odra River, near Malczewski Street in Wroclaw, Poland. In the area, naturally covered with herbaceous vegetation, an experimental 30mx20m facility was established. The following grasses were dominant in the turf: red fescue, cocksfoot, couch grass, soft brome, Kentucky bluegrass, perennial ryegrass. The turf was overseeded in spring 2007, using TOP MIX 4. The standard of sowing was 12 g m-2.

The composition of the mixture was as follows: 25% white clover, cv Riesling, 25% perennial ryegrass cv Respect, 25% perennial ryegrass cv Eminent, 10% meadow fescue cv Manifesto 15% timothy-grass cv Promesie

Such a species composition ensures the achievement of high yields of green mass and corresponding gustatory and nutritional value. From the point of view of traction properties, the aforementioned grasses should be characterized by resistance to compaction by machinery wheels and farm animals hooves. The substrate under the turf was brown acid soil, in some sections gleyic, made from clay loam on silty clay loam. Specific density of soil was 2.48 Mgm-3. The study was carried out before the botanical composition of forage mixtures overseeded in 2006. In 2007 and 2008 turf was used in controlled manner, and then after regeneration its botanical composition was determined. Five different levels of turf compaction were obtained by using a specially constructed traffic simulator. As a result of 140 runs of a

69

tractor with the cleated roller, aboveground parts of plants were completely destroyed and thus the fourth highest level of compaction was obtained (100%). Intact turf (0%) was not compacted at all. Intermediate levels were obtained by 35 runs of the tractor (25%), 70 trips (50%) and 105 trips (75%).

Table 1 shows the species composition of turf in each year. The values given in columns 2007 and 2008 are mean percentage of species at the turf wear at 100%.

Table 1. Composition of the turf in each year Species 2006 2007 2008 Grasses Poaceae [%] Red fescue Festuca rubra 3.6 3.6 3.5 Meadow fescue Festuca pratensis 0.7 1.2 0.6 Sheep's fescue Festuca ovina 2.1 2.7 2.6 Cocksfoot Dactylis glomerata 3.3 3.2 4.0 Colonial bent Agrostis tenuis 1.5 0.8 0.8 Couch grass Elymus repens 14 3.7 7.9 Soft brome Bromus mollis 3.8 3.8 2.3 Tussock grass Deschampsia

caespitosa. 1.6 4.9 4.2

Kentucky bluegrass

Poa pratensis 3.2 3.8 3.6

Annual meadow grass

Poa annua 0.5 2.0 2.3

Timothy grass Phleum pratense 3.8 4.3 3.8 Perennial ryegrass Lolium perenne 4.4 10.7 14.5 Legume family Fabaceae Birdsfoot trefoil Lotus corniculatus 4.3 4.1 3.4 White clover Trifolium repens 2.4 13.2 11.9 Red clover Trifolium pratense 5.9 5.6 8.2 Smooth tare Vicia tetrasperma 4.3 3.1 1.1 Herbs and weeds Ribwort plantain Plantago lanceolata 11.2 9.4 3.2 Grasslike starwort Stellaria graminea 2.1 4.4 4.3 Common yarrow Achillea millefolium 11.4 9.6 9.7 Common Dandelion

Taraxacum officinale

9.4 3.6 4.4

Musk thistle Carduus nutans 3.3 1.1 1.5 Upright bedstraw Galium mollugo 3.2 1.2 2.2

Total [%] 100 100 100

A naturally occurring grass species (2006) which might have affected generation of traction forces was red fescue which occupied 3.6% of the area. It has underground stolons, which enable the formation of a very strong dense turf. It is characterized by a high resistance to harsh habitat conditions and high resistance to compaction. Its characteristic feature is the high content of dry matter. Another naturally occurring grass was cocksfoot (3.3%), easily spreading but not forming a dense turf. It has a highly developed root system. It is resistant to periodic droughts, resistant to the influence of animals and mechanical equipment. Couch grass is a weed constituting 14% of the turf in this study. It is highly resistant to adverse

70

environmental conditions. It produces stolons that beneath the surface of shallow soil may show good binding properties, creating a dense and firm turf. Smooth meadow-grass (3.2%) is a very durable and easily spreading species. It develops a large amount of condensed, flattened vegetative shoots. It is durable and very resistant to harsh habitat conditions, both in relation to water and air temperature; grows rapidly and evenly during the growing season. Among the sown species, several may strengthen and improve turf and increase traction efficiency.

White clover, which after the first wear simulation occupied 13.2% of the area and after the second wear simulation 11.9%. Its root system is shallow, but strongly developed in the topsoil. Stems sprout and root, so that the plant can spread quickly, it takes free space and usually covers wide chunks of the grassland. It is a typical forage plant, resistant to frequent grazing and trampling, and also to harsh climatic conditions.

Perennial ryegrass is a low grass, loosely bunch-type, which creates a smooth, firm turf. It grows exuberantly after grazing, trampling and frequent mowing. Furthermore, in these very conditions it reaches its full potential. In this study, its share increased with time, up to 10.7% and 14.5% in the consecutive years of the study.

Timothy-grass develops a small root mass concentrated in the small subsurface layer of turf. It bears moderate mowing well, but repeated and low shear substantially reduces its viability, resulting in reduced yield and a lower share in sward. It is only resistant to moderate trampling. For these reasons, usage of the examined grassland reduced the growth and development of this plant, its share decreasing down to 4.3% and 3.8%.

In 2009 the turf wear simulation was repeated, and then strength and traction studies were performed. Penetration resistance measurements were carried out using an electronic cone penetrometer, digitally recording forces and the depth of penetration. Its cone had a side angle of 60° and 0.0001 m2 base area. The device had a propulsion system that provided a constant penetration rate of 0.03 ms-1. The plots of penetration resistance in relation to depth at different compaction levels are shown in Figure 1

0

100

200

300

400

500

600

0 0,05 0,1 0,15 0,2

depth of penetration [m]

penetr

ation r

esis

tance [

N]

0% 25% 50% 75% 100%

Figure 1. The plots of penetration resistance in relation to depth of penetration at

different usage levels

71

The plots show that an increase in level of wear resulted in growing resistance to cone penetration. A particularly dynamic increase in penetration resistance was observed for 75% and 100% use, which should influence traction efficiency. For lower levels of wear, a decrease in cone penetration was observed at a depth of 0.02 - 0.04m, which is directly related to the presence of plants and reinforcing the impact of their root systems. Our results suggest that moderate use of the surface with the examined composition of plant species would not result in the compaction of deeper layers of the soil. Compaction calculated on the basis of cone penetration resistance ranged from 2.0 MPa for the 0% use to 5.7 MPa for 100% use, at the depth of penetration 0.2 m. The observed influence of the intensity of use on the increase in the relative compaction of the analyzed turf was the basis from traction examinations, as it was expected that greater compaction will result in better traction.The measurements of traction forces were performed using a versatile station for tyre traction tests in field conditions, constructed by the Institute of Agricultural Engineering, Wroclaw University of Environmental and Life Sciences. Figure 2 shows the diagram of the station. It consists of a support frame connected to an agricultural tractor (in order to provide mobility and independence from external energy sources), a system imitating the real system chassis, a test wheel drive system, and measuring and recording instruments. The station is equipped with a fifth wheel to allow the calculation of wheel slip. The station can perform simultaneous measurements and recording of driving (traction) power generated by the tested drive tyre, torque supplied to the wheel, theoretical and actual path of the tested wheel. Measurements were made for 2 different vertical loads (3300 N and 4300 N). Software and equipment used allowed immediate graphical presentation of results, an important factor in carrying out research in the field.

1

2

6

5

4

37

8

910

Figure 2 The station for traction tests: 1 - tractor, 2 - frame, 3 – shaft with the test

tyre, 4 - separately powered hydraulic system, 5 - torque sensor, 6 - force sensor, 7 - wheel rotation angle sensor, 8 - fifth wheel with a sensor to measure the actual

path, 9 - transmission chain, 10 - electronic recording system connected to a computer

Wheel slip and traction efficiency were calculated according to the following

formula [Jakliński 2006]:

72

δ=1−

srz

st

[ ]

(1)

where: δ – wheel slip Srz – actual path, m St – theoretical path, m

[%])1(rM

Pd

T δη −⋅⋅=

(2)

where: η – traction efficiency,% PT – traction force, N M - torque, Nm rd - dynamic radius, m δ – wheel slip

Measurements of the effective dynamic radius (rd) of the test wheels were

determined separately for each load, based on the measurement of the distance travelled for five complete turns of the wheel. All sensors recorded the measurements to a precision of 0.001 [N, Nm, angle of wheel rotation]. Measurements were performed over five repetitions for each load wheel. The examination of traction properties was performed for an agricultural tyre, size 9.5-24, with an air pressure 0.21 MPa, as recommended by the manufacturer. Technical parameters of the tyre are shown in Table 2. The experiment was also conducted on the same tyre with anti-skid chains with spurs. The results were statistically analyzed using multivariate analysis of variance α = 0.05

Table 2. Technical parameters of the tyre 9.5-24

Tyre

9.5-24

tyre type drive tyre construction inner tube Tread type AN 13 Max. speed [ms-1] 11 number of PR 8 Maximum pressure [MPa] 0.21 Dimensions [m]: Height Width Diameter of mounting

1.048 0.241 0.610

TEST RESULTS AND ANALYSIS

Figures 3 and 4 shows the plots of traction forces generated by the 9.5-24 tyre and the tyre equipped with anti-skid chains on turf with varying levels of usage, as a function of wheel slip, with a vertical load on the test wheel of 4300N.

73

0

500

1000

1500

2000

2500

3000

0 5 10 15 20 25 30

δ [%]

PT [

N]

0% 50% 100%

Figure 3. Plot of traction forces generated by the test tyre in relation to tyre slip

The presented diagrams show that the increase in grassland usage,

manifested by an increase in density, results in greater traction. Both in the case of tyres with and without chains, the maxima of traction generated at various levels of turf wear were obtained at different values of slip. For the 9.5-24 tyre, maximum values of traction were generated on the intact turf (0%) and after 50% wear, at about 8% slip; on completely destroyed turf the maximum traction was achieved at 15% slip. A similar trend was observed for the 9.5-24 tyre with anti-skid chains, which at 0%, 50%, 100% usage of turf obtained maximum traction at slip values of 5, 11, and 24% respectively. This situation is probably associated with the presence of plants and the reinforcing impact of the root systems of the grasses. At 100% usage level, lack of the aboveground parts of plants and strongly reduced root mass resulted in maximum traction forces at higher values of slip.

0

500

1000

1500

2000

2500

3000

0 5 10 15 20 25 30

δ [%]

PT [

N]

0% 50% 100%

Figure 4. Plot of traction forces generated by the test tyre with anti-skid chains in

relation to tyre slip

74

Figures 5 and 6 present the plot of traction of the test tyres on turf soil with turf usage, with a load of 4300 N. The diagrams show that the higher the level of turf wear, the higher the traction at slip range 0-24%. In the case of the 9.5-24 tyre, maximum traction efficiency was determined at over wheel slip range 5-10%. At wheel slip over 25%, there were no differences in traction determined at different turf wear levels. Probably this effect is directly related to the significant compaction of the soil, and the hindered penetration of the protruding tread into sections of the turf. It minimizes cutting performed during traction, losses of energy spent on tread penetrating the turf is smaller. The result is high efficiency, however at a slip greater than for 0% and 50% turf wear.

0

10

20

30

40

50

60

70

80

90

0 5 10 15 20 25 30

δ [%]

η [

%]

0% 50% 100%

Figure 5. The plots of traction efficiency determined for the test tyre in relation

to tyre slip The plots of traction efficiency for the tyre with anti-skid chains on the tested

turfs (Fig. 6) had a different character over the entire analyzed range of slip. It was observed that the maxima of traction efficiency at different levels of turf wear were obtained at different values of slip. On the intact turf (0%), and the turf used at 50%, maximum efficiencies (65% and 74%) were obtained at 5-7% slip, while on the totally destroyed above ground plant parts (100% wear) the highest value of the traction efficiency (85%) was determined at wheel slip 15-18%. The use of anti-skid chains increased the proportion of cutting in the generation of traction forces. But it did not increase resistance enough to induce a reduction in traction. The increase in slip at all levels of use, at which maximum traction efficiency was achieved, may have been associated with the deformation of chain links and partial movement on the tyre.

75

0

10

20

30

40

50

60

70

80

90

0 5 10 15 20 25 30

δ [%]

η [

%]

0% 50% 100%

Figure 6 The plots of traction efficiency for 9.5-24 tyre with anti-skid chains in relation

to wheel slip

In order to establish whether the anti-skid chains contributed to the change in traction properties, Figures 7 and 8 show the maximum values of strength and traction efficiency of tyres with and without chains, on turf with varying intensities of use. Figure 7 shows that irrespective of the level of turf wear, the use of anti-skid chains resulted in higher traction forces compared to tyres without chains. Especially on turf with greater intensity of turf wear (50%, 75%, 100%) the use of anti-skid chains increased traction forces by up to 20%-33%. Figure 8 shows that the use of chains resulted in 2-11% increase in traction efficiency in comparison to values obtained without chains. Interestingly, the same efficiency values for tyres without chains on the turf with greater intensity of use were obtained for anti-skid tyre chains at the lower level of turf use. For example, 73% efficiency can be achieved at 50% wear with a tyre with chains, or at 75% wear without tyre chains. It indicates that the vegetation of the turf significantly affects traction efficiency. In this study, a considerable amount of green mass (50% turf wear) and moderately compacted soil may have contributed to measurable advantages of anti-skid chains.

0

500

1000

1500

2000

2500

0% 25% 50% 75% 100%

level of wear

PT m

ax [

N]

9.5-24 9.5-24 with chain

Figure 7. Maxima of traction forces determined for the test wheels at load 3300 N

76

0

20

40

60

80

100

0% 25% 50% 75% 100%

level of wear

η [

%]

9.5-24 9.5-24 with chain

Figure 8. Maxima of traction forces determined for the test wheels at load 3300 N

Figure 9 shows the maxima of traction forces for 9.5-24 tyres, measured at

different levels of turf wear at two different perpendicular loads, 3300 N and 4300 N. Statistical analysis showed that the increase in turf use significantly increased (more than 10%) traction force compared to the lower level of wear. The values of maximum traction forces generated by the 9.5-24 tyre with a load of 3300N ranged from 1264 to 1970 N. Greater load increased traction by 15% for each of the tested turf wear levels.

0

500

1000

1500

2000

2500

0% 25% 50% 75% 100%

level of wear

PT m

ax [

N]

3300 N 4300 N

Figure 9 Maxima values of traction forces of the 9.5-24 tyre at different loads:

3300 and 4300 N Figure 10 shows the maxima of the traction efficiency for the examined tyre on

turf with varying intensity of wear and two different perpendicular loads. An increase in a degree of turf wear resulted in 7% higher traction efficiency of the tyre. The increase in wheel load also resulted in increased traction efficiency, which depending on turf wear ranged from 2% to 10%.

77

0

20

40

60

80

100

0% 25% 50% 75% 100%

level of wear

η [

%]

3300 N 4300 N

Figure 10. The maximum value of traction efficiency for 9.5-24 tyres with wheel loads:

3300N and 4300 N CONCLUSIONS 1. An increase in turf wear resulted in the achievement of maximum traction forces

by the tested tyres at higher slip values. This is due to a smaller share of plants and greater soil compaction in the immediate sphere of influence of the tyres on the ground.

2. The use of anti-skid chains and an increase in the intensity of turf wear positively influences the traction efficiency, with the maximum efficiency obtained at higher slip.

3. The use of anti-skid chains always resulted in increased force (20-33%) and traction efficiency (2-11%), and therefore can be regarded as an effective improvement in traction.

4. Increase in wheel load by 30% contributed to an increase in traction forces by about 15% and traction efficiency by 2-10%, depending on the level of turf wear.

REFERENCES 1. Antille D.L, Ansorge D., Dresser M.L, Godwin R.J. The effects of tyre size on

soil deformation and soil bulk density changes. An ASABE Meeting Presentation. Paper Number:083879. 2008.

2. Błaszkiewicz Z., Kryszak A. Investigations on the effect of wheel traffic on soil compaction and forage yield in three meadow managements. Grassland Science in Europe 8. 2003, 141-144

3. Botta G.F., Jorajuria D., Draghi L.M. Influence of the axle load, tyre size and configuration on the compaction of a freshly tilled clayey soil. Journal of Terramechanics 39, 2002, 47-54

4. Douglas J.T. Soil compaction effects on second – harvest yields perennial ryegrass for silage. Grass and Forage Science. 52. 1997, 129-133

5. Głąb T.: Analiza przyczyn zmian plonowania wybranych gatunków traw pod wpływem wielokrotnych przejazdów kół ciągnika. Inżynieria Rolnicza. Rozprawa habilitacyjna. Nr 3 (112). 2009.

6. Jakliński L.: Mechanika układu pojazd-teren w teorii i badaniach. Wybrane zagadnienia. Oficyna Wydawnicza Politechniki Warszawskiej. 2006.

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7. Keller T., Arvidsson J. Technical solutions to reduce the risk of subsoil compaction: effects of dual wheels, tandem wheels and tyre inflation pressure on stress propagation in soil. Soil & Tillage Research. 79, 2004, 191-205

8. Li. Q., Ayers P. D., Anderson A. B. Prediction of impacts of wheeled vehicles on terrain. Journal of Terramechanics 44, 2007, 205-215

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Chapter 8

UTILIZATION OF PID CONTROLLER TO STEERING OF SOLAR SEGMENT

OPERATION

Paweł OBSTAWSKI INTRODUCTION

The estimated prognoses suggest a slow using up of mine fuels, causing the

increased interest in renewable sources of energy [Domański 2006, Trajer et al. 2005]. With respect to low density of green energy and its unstable potential throughout the year, the renewable sources of energy replenish conventional sources of energy and create the hybrid systems of power supply. In Polish conditions the most common basic segment of hybrid system is sunny segment, but with flat fluid collectors the system is supplied with heat energy in period March - September.

In construction of flat solar collector it is possible to distinguish three homogeneous corpuses: absorber, glass cover as a thermal protection of the absorber, and working medium (functioning as a carrier of energy) [Chochowski 1991]. The flow of working medium can be free or forced with the help of circulating pump. As the result of working medium flow, most often based on glycol, the absorbed heat energy is transferred to the magazine of warm usable water.

The main problem in thermal energy hybrid systems is low efficiency of their several segments and in result the low efficiency of a whole system. The important fact is, that several components of system working as single systems achieve much higher efficiencies. It is possible that low efficiency of several components of hybrid system does not result from the nature of energetic transformations, but from bad design - too small or too big in relation to user’s demands of system components. Too big size of hybrid system segments will cause, that system will not fulfill the customer’s requirements. Too big segments’ size increases considerably costs of installation and if heat energy is not received by solar segment system, too high temperature can unseal the hydraulic installation. Therefore, too large size of solar segment is particularly dangerous

Low efficiency can also be caused by bad design of the system for steering of hybrid system operation. Hybrid system related to size of individual components should be designed according to customers’ requirements. Therefore, a separate system of steering with specific algorithm of operation should be designed for every

80

hybrid system. Usually, the standard double-throw controllers are used to steer operations of hybrid systems and solar segments.

ANALYSIS OF FLAT SOLAR COLLECTOR OPERATION IN THE SYSTEM OF DOUBLE-THROW CONTROL

The solar collector is a device transforming energy of solar radiation into heat energy [Chochowski et al. 1999]. In solar collector operation it is possible to distinguish two thermal states: steady state and transient state. Thermal states in flat solar collectors were investigated by many authors [Duffie et al. 1974, Cholewczyński et al. 1981, Domański 1990]. They described the effect of accumulation and transformation of heat energy in steady and transient states. One should note that steady state of solar collector occurs in laboratory tests only, because thermal states of a flat solar collector depend not only on its constructional parameters, but also on external medium under operational conditions, when solar collector is in transient state. The main factors that influence operation of fluidic solar collectors are [Obstawski 2007]:

a) dose of sun irradiating, b) inlet temperature of working medium, c) flow of working medium, d) taking to pieces usable warm water aggregated in accumulator, e) surroundings’ temperature, f) direction and speed of wind.

The exchanged media establish the point of solar collector operation. The

largest influence on solar segment operation during the day have 24-hour schedule of solar radiation, taking to pieces warm usable water, average temperature of surroundings and steering algorithm, according to which the work of solar segment will be realized.

Usually steering of work solar installation is realized with the help of double-throw controller, with implemented standard control algorithm, depending on switching on and switching off the circulation pump of constant output. The pump is included on the ground lapse rate between working medium and liquid in accumulator of warm usable water.

When does not be reach set gradient between output temperature of working medium and liquid in accumulator of warm usable water, the circulating pump forcing the flow of working medium is stand. Then follows the increase of temperature of medium being in solar segment and decrease on result of losses temperature medium being in hydraulic installation. In moment when set gradient be becomes reached between exit temperature of working medium and temperature in accumulator warm usable water, enabling switching on circulating pump follows the forced flow of working medium. On result forced flow of medium initially follows his chilling witch is result necessity of compensation temperature of medium to temperature of hydraulic installation. The temperature of medium aims in adverse party than intentional. When the temperature of working medium and pipeline becomes even, follows transportation of heat accumulated energy by working medium - increase of temperature. Therefore after power-up circulating pump step out the losses heat energy in pipeline. Even well isolated hydraulic installation during lay-off of circulating pump considerably lose temperature. Power-up circulating pump in first phase causes rendition of accumulated heat energy on covering losses energy in pipeline.

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When become reached set gradient between output and input temperature working medium circulating pump becomes switched off. However with regard on large thermal inertia of system the value of temperature of working medium still grows up what in case of good sunny conditions and lack of taking to pieces can to lead to short-lived high temperature. On result of thermal losses temperature of medium reduce to set value and by some period of time is thereon level provide. With reason thermal losses to surroundings or taking to pieces of warm usable water follows drawdown temperature in accumulator of warm usable water, which appear increase lapse rate between output temperature and temperature in accumulator warm usable water and follows enclosure circulating pump. Then process repeats oneself [Obstawski 2007].

In case of intensive partitions the warm usable water and low-level of intensity of solar radiation reduce level of temperatures of working medium. The low-level of temperatures of medium makes possible intensive accumulation of heat energy and also work of sunny installation on considerably lower temperatures which can in result cause power-up the conventional source of the power supply.

Therefore the largest and also direct influence on average value of temperature of working medium achieved in during of day in solar installation has dose of solar radiation put on absorber surface. Important meaning on achieved values of temperatures in solar segment has also size and schedule in during of day partition warm usable water. Exact correlation between partition of warm water and inlet temperature of working medium causes that the recruitment of warm usable water in installations reduces its temperature in accumulation magazine ( in its place comes in cold water). The same reduce inlet temperature of working medium in collector. In case when the solar conditions are good however does not exist partition of energy accumulated in system the temperature of working medium increase what provoke too high temperature in absorber construction. At the same time with increase temperature grows up pressure in hydraulic installation what can to lead to its unseal and infecting.

Elimination in sunny segment high temperatures can be possible to realize across indirect accumulation of overage surplus of energy in ground if in hybrid system is pump of warmth with ground exchanger or by its stockpiling in buffer tank. Installation in system buffer tank considerably raises costs of investment and in not every system has the pump of warmth.

Probably the elimination too high temperature and enlargement the efficiency of solar segment can be realize across use of circulating pump about smoothly controllable with the help of the PID controller [Bajkowski 1994] expense forcing the flow of medium in solar installation, because increase of temperature working medium in sunny segment has also influence speed of flow of medium [Czekalski et al. 2003]. If flow of medium in hydraulic installation is smaller, that the value of flow of stream mass is smaller and in result the increase of temperature of medium is larger. When the flow of medium increase the flow of stream of mass increase which causes enlargement the losses to surroundings and the same smaller increases of temperature. However does not recommend turbulent flow in hydraulic installation because increase hydraulic resistance which causes the growth of recruitment of electrical energy used up to drive of circulating pump [Czekalski et al. 2003 ]. Therefore, monitoring of speed of flow medium in hydraulic installation is necessary.

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MODEL OF SUNNY SEGMENT

To investigate energetic efficiency of solar segment, controlled with the help of PID regulator, simulation was made with utilization of the model worked out with the help of parametric identification with black box method [Obstawski 2007]. Parametrical identification makes possible creation mathematical description modeled system in differential equation form on the ground of registered input and output signals [Janiszowski 2002]. The created model was on the ground of real measuring data coming from monitoring of work of hybrid system feeding with heat energy the hotel in Regional Centre of Ecological Education in Budy Grabskie [Chochowski et al. 2008].

Sunny segment of system (Fig. 1.) consists with twenty fluidic flat solar collectors joint with accumulator about capacity 1000 dm3, with the help of exchanger. The work of segment control is realized with help double-throw controller enclosing circulating pump about solid expense forcing the flow of working medium when gradient between output temperature with medium and liquid in accumulator will reach value 5K. In case of lack of partition warm usable water, in aim the elimination possible too high temperature double-throw controller encloses the circulating pump on 5 minutes that 20 minutes.

Figure 1 Segment of flat solar collectors

In identification process solar segment of was treated as double inputs and

single output object which can introduce with the help of following block scheme (fig. 2) [Obstawski 2007]. For input signals accepted: input temperature of working medium and 24 hour distribution of intensity of solar radiation. As output signal accepted output temperature of working medium.

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The analysis will be conducted on the ground data registered in days about considerably differing points of work.

On day 20.06.2002 the cloudless sky caused that conditions for work of collectors section were very good (Fig. 3). The accumulated heat energy collectors began supply to warm usable water accumulator in 9:0 am when temperature working medium reached the higher value than temperature of liquid in accumulator. The process of conversion of solar energy what put on surface of collectors on heat energy lasted till 5:0 pm, when temperature of liquid in accumulator of warm usable water reached value even temperature of working medium of collectors. In result very low partition in day 19.06.2002 (day earlier) initial temperature of liquid in warm usable water accumulator shaped on very high-level 78 [°C].

Figure 2. Block scheme of solar segment

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Figure 3. The 24-hour schedule of solar radiation and temperatures on 20.06.2002

In this day the partition warm usable water intensely happened in morning

hours and was equal 442,5 [dm3]so temperature of water in accumulator lowered oneself to 70 [°C] and she determine the initial temperature for work solar segment. In 5 pm hour the temperature in accumulator even with temperature of working medium of segment collectors and was equal until 90 [°C]. The dose of energy solar radiation which put on the surface of collectors was high and equal 911,93 [MJ], however to accumulator of warm usable water was passed only 136,97 [MJ] of accumulated energy. The efficiency of transformation in flat collectors segment reached low-end 15%. Small partition of warm water (442 [dm3]), very good working conditions and high initial temperature in warm usable water accumulator caused that the maximum input temperature of working medium of battery collectors reached value 105 [°C], and the output temperature of working medium with collectors segment was equal 117 [°C]. In result so high-level of temperatures in sunny installation the temperature of constructions parameters was too high.

On 23.07.2004 differently than on 20.06.2002 the working conditions were shaped on changing level (Fig. 4).

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Figure 4. The 24-hour schedule of solar radiation and temperatures on 23.07.2004

Despite, that in about of 12.00 hour pyranometer recorded the very high

temporary value of intensity of solar radiation equal near 1000 [W/m2], then in result of frequent transitory cloudiness energy of solar radiation which reached on surface of collectors was equal only 561,1 [MJ]. In result intensive and proportionate partition of warm usable water and very low value of sunny intensity between hour 11:30 am and 12:30 pm as well as 3:30 pm and 4:30 pm equal about 280 [W/m2] the temperature of working medium fell about 20 [oC]. Therefore there is visible the exact correlation of partition of warm usable water with input and output temperature working medium of collectors. On that day the 24 hour partition of warm usable water was equal 1975 [dm3]. The special attention also should turn on small gradient between the input and output temperature working medium in section flat collectors which was equal 2-3 [oC]. So small lapse rate is effect frequent transitory cloudiness’s and the large, intensive, evenly partition of warm usable water. The maximum input temperature of working medium to flat collectors segment was equal on that day 80 [oC], and the maximum output temperature of working medium with segment of collectors assume a shape on level 92 [oC]. Temperature in accumulator of warm usable water was shaped during whole day on level 50 - 55 [oC] that in the latter part day to reach value 63 [oC]. To accumulator of warm usable water with flat collectors section delivered 216,7 MJ accumulated solar power of, that efficiency of transformation was equal 38%.

The parameters of work of solar segment for analyzed days were introduced in table 1.

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Table 1. Parameters of work of solar segment data dose of

solar radiation

[MJ]

max. input temperature

[ºC]

max. output temperature

[ºC]

partition of warmusable water [dm3]

max surroundings temperature

[ºC]

max. temperature

in accumulator

[ºC] 20.06.2002 911,93 105 115 442 38 92 23.07.2004 561,1 80 94 1975 33 63

PARAMETRICAL MODEL OF SUNNY SEGMENT

In parametrical identification process worked out mathematical models for analyzed days in differential equation form at equal structure ARX322 [Obstawski 2007]. The mathematical model describer changes of output temperature of working medium at changes irradiation and input temperature of medium for day 20.06.2002 expresses arrangement of transfer function 1 and 2. The mathematical model describer changes of output temperature working medium at changes of irradiation and input temperature of medium for day 23.07.2004 expresses arrangement of transfer function 3 and 4.

( )1q*0,528q*0,3755q*0,022

q*0,009486q*0,01109zG

123

23

1

−−−

−

=−−−

−−

(1)

( )1q*0,528q*0,3755q*0,022

q*6369,0q*0,5239zG

123

23

2

−−−

−

=−−−

−−

(2)

( )1q*0,8891q*251,0q*0,05952-

q*003663,0q*0,0002246-zG

123

23

1

−−+

+=

−−−

−−

(3)

( )1q*0,8891q*251,0q*0,05952-

q*2965,0q*0,005605zG

123

23

1

−−+

+=

−−−

−−

(4)

In aim opinion of propriety worked out models conducted their verification made simulation of 24 hour process of output temperature. In this aim on input of models introduced the real courses of solar radiation and input temperature medium for individual days and compare with real process of output temperature medium. The results of verification were introduced on Figure 5 and 6.

The process of simulated temperature overlaps on process of real temperature which provide very good return propriety of sunny segment through worked out models. The calculated coefficient of correlation for day 20.06.2002 is equal 0.997, however in case of day 23.07.2004 is equal 0.996.

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Figure 5. The comparison of real process of output temperature with simulated one

for 20.06.2002

Figure 6. The comparison of real process of output temperature with simulated for

27.07.2004

ANALYSIS OF ENERGETIC EFFECTS AT USE OF PID REGULATOR TO STEERING WORK OF SUNNY SEGMENT

Use of PID controller to steering work of sunny segment have in view

elimination of too high temperature in sunny installation, which appear under very good sunny conditions, low partition warm usable water, and enlargement in sunny segment temperature of medium at large evenly splitting partitions warm usable water. Use PID controller joins with use circulating pump with smooth control of

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outlay because steady effect is possible to reach across smooth control of flow medium by solar installation. In case when the sunny conditions are very good and is low partition of warm water the regulator should enlarge to maximum (below turbulent flow) outlay of pump, which would be effective the increase losses and in result decrease temperature of medium. In case when in system appear large partition of warm water and the sunny conditions are good to work installation controller should reduce the outlay of circulating pump and in result the flow stream of mass in unit time will be smaller and of temperature of medium will increase.

Simulation research were conducted in simulink packet with utilization the models of sunny segment worked out for days: 20.06.2002 and 23.07.2004 in parametrical identification process.

The scheme of control work of sunny segment was introduced on Figure 7. In notepad "flat solar collector ” is worked out parametrical model in differential equation form. In identification process model was worked out as double inputs and single output. On first input "In1 ” was introduced the real process of solar radiation, however on input "In2 ” real process of input temperature of medium. Output signal of model is process temperature of medium which is introduced to oscilloscope enabling visualization and filing of his process. Applied in simulation system of control is innovative because consists with two PID regulators joint parallel. Use of such system of control demand the specific of steering work of sunny segment. Task first PID regulator is generating adjustable signal in such way that set difference between input temperature and output temperature of medium will be well-kept. The input signal of regulator is deviation of control being difference of lapse rate between output and input temperature medium and set value "set point 1”. Task second PID regulator is generating such adjustable signal to keep set lapse rate between output temperature medium and temperature in magazine warm usable water.

Figure 7. Scheme of control system

The input signal of second regulator is deviation of control between

temperature in magazine and the output temperature of working medium. How it results with Figure 7 the adjustable signals of regulators be added up in sum knot. Such configuration system of steering is possible on condition re - calibrations ranges output signals of regulators so to maximum sum of adjustable signals generated through regulators return the maximum value of analog adjustable signal passed on steering input pump.

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Therefore in system of control change of input temperature of medium, solar radiation and fall of temperature of water in accumulator caused water partition is random disturbances which regulator should oppose across generating suitable adjustable signal.

The day 20.06.2002 had very good the sunny conditions and low partition of warm usable water. The high temperature in accumulator equal 68.8 [°C] prove that partition of warm water in previous day was low. The large dose irradiation, high initial temperatures and low partition heat energy in system caused that in sunny segment temperature of constructions was too high and water in accumulator reached temperature 92 [°C]. In moment when the gradient between temperature of medium in circulation of collectors and accumulator warm usable water made possible the power-up through double-throw controller circulating pump was happened accumulation of heat energy. Regulator with stiffly set lapse rate steered work of sunny segment unresponsively on high-level of temperatures in system which from 10:30 am to 4:30 pm was above 100[°C] .

If to steering work of system applied be scheme with Figure 7 process of accumulation of energy would look differently. In analyzed case regulator PID_1 and PID_2 should generate adjustable signal which would cause the maximum expense of circulating pump, and the same increase losses, which would reduce increase of temperature medium in circulation of collectors and liquid in accumulator. But firs appear very important question: what should be set regulators values?

On Figure 8 introduced spurious process of temperature at different values of set regulators PID_1 and PID_2.

In all analyzed set values is clearly visible that in initial phase of work the process of warm of medium becoming considerably slower than in reality. The process of heating becomes a little more intensive really for 12:00 pm. The lowest values of temperature of medium in solar installation has got for value SP_1 = 1 and SP_2 = 2. Maximum value of temperature for this process does not cross 98[°C] and is lower from real about 17[°C]. Near increase lapse set rate, which have to keep regulators PID_1 and PID_2 steering the outlay of pump the level of temperature of medium grows up and for set SP_1 = 5 and SP_2 = 5 maximum temperature of medium in circulation of collectors reached value 104[°C] that is about 11[°C] lower from real temperature. In analyzed case the nuance of applied solution is the higher level of temperature of medium from real after hour 17.30. This situation is result put set values. Comparing consequential with simulation efficiency of sunny segment is it approximate to real.

In case of day 23.07.2004 was completely different operate the conditions of system. This day was changing atmospheric condition and high equal during whole day partition warm usable water. Till hour 10:00 am when the temperature of medium in solar segment was lower than in accumulator the warm usable water temperature of liquid in accumulator on level 50[°C] keep up the heat pump. When so appear conditions favorable to work of solar segment double-throw controller power-on circulating pump. In process of output temperature of medium can see, that at realized by system solid outlay of circulating pump longer falls value of radiations are effective immediate fall of temperature.

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Figure 8. Comparison of simulated process of input temperature of working

medium with real

On Figure 9 represented the simulated process of output temperature at the same values of set size like in previous case. To be clearly visible that simulated temperatures achieve similar process like real temperature however theirs temporary values are lower. Cause of such result is put on solid sizes of set value.

Therefore at changing atmospheric condition and large partition warm usable water size of set value of regulators should be changeable. For example between 11:30 am and 1:00 pm when appeared the considerable fall of irradiation set value of regulator PID_1 should be larger for example: should be 10 [°C]. Then regulator would reduced the outlay of pump and caused smaller flow of mass in unit time what probably would caused the larger increase of temperature of medium in solar installation and also increase efficiency of solar segment.

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Figure 9. Comparison between simulated input temperature of working

medium and real one CONCLUSIONS

The presented steering system of solar segment operation in hybrid system

makes possible to increase the energy efficiency of solar segment, although too high constructional temperatures are limiting factors in this segment. The applied system of steering has also some limitations. One of them is summing up of the signals of both regulators, leading to parameter values that determine the point of segment’s operation resulting in mutual cancellation of regulators’ work. The next problem is selection of suitable individual modules of regulators, which are dependent upon dynamic parameters or, alternatively, on the variable values of work parameters in the sunny segment, Similar problem is in size selection of the set value, which generally affects an increase in efficiency of alternative energy. Therefore, it is necessary to study the presented system algorithm and to determine the exchanged parameters values so that they will be suitable to circulating working conditions; investigating the adaptive system to control the sunny segment operation is also necessary.

REFERENCES 1. Bajkowski B.: Automatyka, Wydawnictwo SGGW, Warszawa 1994 2. Chochowski A. : Analiza stanów termicznych płaskiego kolektora słonecznego.

Wydawnictwa SGGW, Warszawa 1991 3. Chochowski A., Czekalski D.,: Słoneczne instalacje grzewcze. Centralny

Ośrodek Informacji Budownictwa, Warszawa 1999 4. Chochowski A., Czekalski D., Obstawski P.: Monitorowanie funkcjonowania

hybrydowego systemu odnawialnych źródeł energii. Przegląd Elektrotechniczny 8/2009

5. Cholewczyński L., Pluta Z.: Charakterystyki płaskich kolektorów energii promieniowania słonecznego. COW nr 2-3, 1981

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6. Czekalski D., Mirski T.: Wpływ wydajności pompy obiegowej na efektywność instalacji słonecznej Polska Energetyka słoneczna nr1, 2003

7. Domański R.: Magazynowanie energii cieplnej. PWN W-wa, 1990. 8. Domański R.: Źródła i konwersja energii w przyszłości w Polsce i na świecie.

Energetyka, zeszyt tematyczny nr IX, 06/2006 9. Duffie J., Beckman W.: Solar Energy Thermal Processes J. Willey and Sons,

New York. 1974 10. Janiszowski K., Identyfikacja modeli parametrycznych w przykładach.

Akademicka Oficyna Wydawnicza EXIT. Warszawa, 2002 11. Obstawski P.: Modelowanie dynamiki pracy płaskiego kolektora słonecznego.

Rozprawa doktorska, SGGW 2007 12. Trajer J., Czekalski D.: Prognozowanie sum napromienienia słonecznego dla

potrzeb energetyki słonecznej. Inżynieria Rolnicza 8/68, Kraków, 2005

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Chapter 9

USING OF LED LIGHTING TECHNOLOGIES TO SUBSTITUTE TRADITIONAL LIGHTING

SYSTEMS IN GREENHOUSES Nuri CAGLAYAN, Can ERTEKIN INTRODUCTION

One of the major parameters that influence plant growth is the availability of

light. Greenhouse plant production systems have the capability of providing supplemental lighting during plant growth in cases where daylight is insufficient for optimal crop production. Supplemental lighting is provided to increase photosynthesis in plants and is often referred to as ‘‘assimilative lighting’’ because its main purpose is to increase the growth, that is, the assimilation of CO2 in the crop [Ciolkosz et al. 2001].

Supplemental lighting in greenhouse facilities is provided by specially designed lighting systems, which, in the case of assimilative lighting (as opposed to morphogenetic lighting where light is provided to control the plant form and not growth), usually consist of high intensity discharge lamps in direct reflectors, mounted in a grid pattern above the plants. The performance of these systems is measured in terms of uniformity of the light supplied and average light intensity provided [Deitzeret al. 1994]. These properties are inherent of the design characteristics of the lighting system, the goal of which is to provide a highly uniform light level over the entire growing area in order to facilitate uniform crop production [Ciolkosz et al. 2001].

The structure and operating conditions of greenhouse plant production facilities make design of supplemental lighting systems a complex process. Many interactions exist between lighting systems and plants, such as photosynthesis, photo morphogenesis and thermal effects, and between lighting systems and parts of the greenhouse structure (e.g. reflections of the cover) and mechanisms of the production system (e.g. shading by other mechanisms). In addition, design properties of the lighting system are limited by several factors of the greenhouse production system, like the type of cultivated plant, greenhouse layout, available greenhouse height and desired light intensity level, light distribution of the luminaires and their power consumption and the availability of electric power. Electrical efficiency of the lighting system is the most important parameter in the majority of studies in system design [Bubbenheim et al. 1988; Albright, Both 1994; Sager 1984; Both et al. 1997 ].

94

A more detailed study by Ciolkosz et al. [2001] gave some useful results on the effects of luminaire selection and layout on the level of uniformity of the provided light of supplemental lighting systems.

When installing supplemental lighting systems in greenhouses, several factors should be considered. Especially at the higher latitudes, and during the darker months of the year, the amount of solar radiation reaching the plants in a greenhouse is insufficient to sustain adequate growth rates. Some growers decide not to use the greenhouse during such conditions, while others use supplemental lighting to boost plant production. Without careful analysis of all economic factors involved, the use of supplemental lighting is frequently perceived as too expensive. It is true that these systems are expensive to install and operate, but with supplemental lighting, crops grow considerably faster during a period of the year when prices are generally higher. If a grower is not convinced the use of supplemental lighting can be profitable, a small-scale trial might be a good way to investigate the possibilities without major capital expenses.

Artificial light sources (e.g., incandescent, fluorescent, and especially high intensity discharge lamps) can be used to supplement the (limited) amount of solar radiation received by a greenhouse crop on darker days. Therefore, a discussion on supplemental lighting should consider the effects of solar radiation on the light environment experienced by greenhouse crops. High Intensity Discharge lighting systems have revolutionized indoor gardening in the last two decades. They are the most energy efficient grow light available, so they produce much more light for the amount of power consumed.

Traditional T12 and T8 fluorescent fixtures are simply not powerful enough to light an area more than 20-25 cm below the bulb. With the recent introduction of T5 technology, T5 linear fluorescents can now put out a respectable 92.6 lumens per watt. T12 lamps typically put out about 30 lumens per watt. T5 fixtures are excellent for starting seeds and cuttings but are also able to produce enough light for full term growth. Because of their minimal heat output, they can be placed very close to the plant canopy to maximize the light output.

Incandescent lamps - these standard household bulbs do not emit enough light, or the proper spectrum, to be used by serious gardening enthusiasts. They are not very efficient, using a considerable amount of power for the light they emit. They are typically only about 15 lumens per watt [Both 2000].

LEDs (Light Emitting Diodes) are just tiny light bulbs that fit easily into an electrical circuit (Fig.1). To most people, the term LED still only means the small indicator lights that show whether the TV set is switched on. But unlike ordinary incandescent bulbs, they don't have a filament that will burn out and they don't get especially hot. They are illuminated solely by the movement of electrons in a semiconductor material and they last just as long as a standard transistor. These tiny light sources barely emit enough light to make themselves visible. However, breakthroughs made in the last few years now allow LEDs to be used for ‘real’ lighting applications that have traditionally been the domain of incandescent lamps and discharge lamps. The development of LEDs is progressing at such a pace that they are rapidly gaining importance for lighting applications, such as traffic lighting and office lighting. The production of LEDs still quite expensive, but some important technological steps have been made in the last year and as a result the price is falling.

95

Figure 1. Constituents in construction of a LED

Although, LEDs that produce a practical spectrum of visible light have been

under constant development since the 1960's, only recently have LEDs that can produce acceptable levels of illumination - for a primary lighting source in a home or business - seen mass production. The pace of innovation in the field of LED illumination, also referred to as Solid State Lighting (SSL), is currently progressing at an amazing pace.

Some important advantages of LEDs: • Long life (more than 50 000 hours) – This is 10 to 50 times longer than a typical

Sodium/HID grow light bulb, • Low maintenance cost - The better ones on the market use up to 90% less

electricity than comparable Sodium/HID bulbs, • Robustness and high reliability, • Saturated colours, • Cool beam, most LED grow lights operate at just a few degrees above room

temperature, thus reducing your grow room cooling costs, • No UV or IR – wide application possibilities, • Low-voltage operation, more light per watt, more safety, ease of use, • LED Lights do not contain mercury, less environmental hazard, metallic vapour

and fluorescent lamps all contain mercury, a heavy metal identified, • Can be emitting light of an intended colour for example, the light which induces

plant growth. • Can be focused on the target and dimmed • Can be pulsate which can increase the energy efficiency by 30%. Disadvantages include: • Significantly more expensive than regular lighting. • Although LEDs are available in many colours, the quality of the colours is not

quite as good as with regular lighting. LEDs are solid-state devices, built up from crystalline layers of semiconductor

material. The light generation process makes use of the special electronic properties of crystalline semiconductors in a process called injection luminescence. This means the injection of charged particles by an electric field from one semiconductor layer into another, where they are able to relax to a lower-energy state by emitting visible light. LEDs produce narrow light spectra. The bandwidth remains limited to a few tens of nanometers and is therefore perceived by the human eye as a single, deeply

Anode

LED

Cathode

Reflecting

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saturated colour. LEDs are now available in all wavelength regions of the visible spectrum; yellow is the only region in which no high-power LED is currently available. White light can be produced by combining LEDs of different colours (for instance red, green and blue) or by applying phosphor coatings on blue or ultraviolet LEDs. Like many other lamps, LEDs cannot be connected directly to the mains. The LEDs have to be operated at a stabilized low voltage, which is provided by a Switch Mode Power Supply (SNMP). However, LEDs do not need ignition and can be switched within milliseconds. LEDs do not generate nearly as much heat as many other lamps, but that does not mean that thermal design is not important. LEDs do produce heat when they operate and are themselves relatively sensitive to temperature. Thermal considerations are therefore very important aspects of LED lighting system designs. Red and blue light is essential for plant growth. It is well known that chlorophyll, which is contained in the green leaves of plants, performs photosynthesis. Red and blue are the wavelengths most essential for photosynthesis [Bubbenheim et al. 1988] The requested wavelength of light by chlorophyll and various light sources were shown in Fig. 2.

The human eye is very sensitive to light in the yellow and green regions (500-600 nm). HID lights produce a large amount of yellow and green light, so they look very bright indeed to the human eye (Fig. 3). LED lights have much less energy in the yellow-green area, so they do not look nearly as bright to eyes as HID lights.

Figure 2. The requested wavelength of light by chlorophyll and the light sources

(LED, Fluorescent and Metal Halide)

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Figure 3. Relative spectral intensity of LED lights, HID-MH grow light, together with

the human eye response curve (LGL Technologies Inc.) Plants only use a tiny percentage of the full light spectrum that old fashioned

grow lights emit. In fact chlorophyll is green for a good reason; plants use this colour as a type of "Sun-block" to remove 95% of the unwanted and damaging light wavelengths. Red/blue LED lighting have such narrow bandwidths that plants without green chlorophyll would actually survive and never be damaged by the LED's perfect and tailor made light wavelengths. Nearly 100% of the light an LED grow light emits is completely absorbed by the plant. LED's can also be left on 24 hours and day without stressing plants since the chlorophyll does not have to do battle with unwanted light-waves. The irradiance power factor or amount of light that actually gets used in plant growth or chlorophyll production can be factored at a rate of 400µmol/m2sec per every 150 LED's average since they have an extra high “Candela” output.

All other grow lights except LEDs emit mainly wasted light energy that does not help the plant produce chlorophyll. In fact 95% is wasted since plants only use very narrow bandwidths of the total light energy. Rating light output in simple terms like lumen or lux is extremely misleading especially when rating a grow light which has a very specific job, like creating chlorophyll 'a' and 'b' .

Red Light: Red light is in the vicinity of the first peak of a plants light absorption spectrum (660nm) and it contributes to the plant photosynthesis. Red light, when combined with blue light, encourages flowering. It can also be used in higher doses to stimulate flowering, seeding and fruiting.

Blue Light: Blue light is responsible primarily for vegetative growth (leaf). It is known that chlorophyll has the second distinct absorption peak in the vicinity of blue light wavelengths (450nm). The blue light is also indispensable to the morphologically healthy growth plant. There is also more sunlight energy in the blue-green wavelengths.

LED grow lights deliver the colours of light used by plants for efficient and healthy growth. By leaving out the wavelengths plants won’t need, they provide better energy efficiency than conventional grow lights. Recent research suggests that the ideal balance is 92% of red LEDs and 8% of blue LEDs. Blue has a smaller influence than red light, so anything between 1 and 20% of blue light can be selected depending on plants and their growth requirements. When choosing lamps, both colours with the same frequency and relative intensity per LED should be considered.

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For the past few years, researchers (Department of Physics and Astronomy at the University of St. Andrews, UK) have been studying the effects of light on plants for which daylight provides most of the light for photosynthesis [9]. Specifically there are some studies on how low intensities of LED light (on the order of 1 W/m2) can be used to control specific features of growth. Three Cineraria plants were grown in daylight, two of which had additional LED lighting. The ones with LED lighting came into flower two weeks before the without ones. However, near-IR light produces slightly paler plants with longer stems, which is commercially undesirable. Blue LED light produces compact plants with good colour. The effects of near-IR radiation on the left, no LED illumination in the middle and blue LED illumination on the right were shown in Fig. 4.

Figure 4. The effects of LED light on Cineraria plants (Department of Physics and

Astronomy at the University of St. Andrews, UK)

In the other study (Faculty of Agriculture, Department of Agricultural Machinery at Akdeniz University, Antalya, Turkey) the effects of differently light sources on tomato plant were determined. The plants have been exposed under the blue and red LED lights, incandescent-lamp and daylight during four weeks and 14 hours a day. Wattage of light sources are selected as 10 Wh. End of the four weeks, it seems that vegetative growth of plants which are under blue-red LED light, increased according to incandescent lamp and daylight (Fig. 5). 125 red LED and 25 blue LED were used in this LED lamp (All experiments were performed at temperatures of 24ºC).

Most growers, who use artificial lighting systems in the greenhouse, use high-pressure sodium (HPS) lamps such as SON-T, because the light spectrum emitted from these lamps fits best to the Photosynthetic Active Radiation (PAR) required by plants for photosynthesis. However, the efficiency of these traditional lamps is very low because the lamps produce enormous amounts of heat.

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Figure 5. The effects of different light sources on vegetative growth of tomato plants

(from placing into the ground to end of fourth weeks) It is estimated that only 30% of the energy put into the lamps is actually used

by plants for growth. This implies an undesirable loss of energy as well as the heat which affects the greenhouse climate. Several prototypes of LED lighting systems have since been developed for greenhouses and have been presented. However, the implementation of LEDs in greenhouse is still at a very early stage so it is expected to take several years before the technology is ready for commercial use in horticulture (Fig. 6). The use of LEDs in laboratories with ‘in vitro culture’ could be used earlier because the efficiency of LEDs is comparable to fluorescent light. Also the use of LEDs in multi-layered cultures is already being considered as an interesting alternative. Some parameters of LED grow lights and other light sources were compared in Table 1.

INDESCANT

LAMP

RED + BLUE LED

LAMPDAYLİGHT

100

Figure 6. Various LED grow lights types and their applications (Ledtronics, Inc.)

101

Table1.Parameter comparison of LED, HPS, Incandescent and Fluorescent Lamp

Replacement LED Grow

Lights HPS Lamp

Incandescent Lamp

Fluorescent Lamp

Light efficiency

80 lm/W 100 lm/W 20 lm/W 80 lm/W

Replacement 90W 250W 600W 300W

Feature of Lighting Source

Solid State Lighting

Gas Discharge Lighting

Solid State Lighting

Gas Discharge Lighting

Lifespan >50000 hours

8000 hours 3000 hours 10000 hours

Environment-Friendly

No PollutionPollution by Mercury &

Lead No Pollution

Pollution by Mercury

Starting Waste

Normal Input

Current

Instant Big Current

Tallish currentInstant Big

Current

Starting Time ns Degree >1 Min. >150 µs >800 µs

CRI High (>80) Low (<50) High (>95) Mid (>75)

Transformer Power Consumption (loss)

15W 50W 0 45W

Working Voltage

DC High voltage110V/220V

AC High voltage

The researchers (The University of Minnesota, Department of Horticultural

Science) have been comparing LED and High Pressure Sodium (HPS) effects on plants. In this study one LED kit (8 red LED bulbs, 4 blue 70 diode bulbs, 12 track light fixtures, 2 - 4 tracks, 2 cord sets) plus 40 diode blue bulbs and one HPS HID lamp (400 watts) was placed 180 cm above the bench for supplemental lighting. LED lights were installed at the same height as the HPS HID light. LED and HID lights were positioned to ensure that each treatment received an equal level of photosynthetically active radiation. Bench height in the LED treatment was modified to a position of ~90 cm below the LEDs. Data was collected on plant height, measured weekly for seven weeks.

Plant height varied significantly across weeks, as would be expected for plant growth (Table 2). The LED treatment had a mean height of 15.24 cm and the HPS HID lights were 13.91 cm tall. There was no statistically significant difference between the LED and HPS HID lights for plant height. Nonetheless, LED lights appear comparable for plant growth in this experiment and LED lights may be an acceptable alternative to HPS HID lighting in greenhouses.

Table 2 and Fig.7 shows results obtained LED lights and high pressure sodium (HPS) lights [Klaassen et al. 2005]. Mean plant height of Capsicum annuum

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‘Hungarian’ and Bellis perennis ‘Monstrosa’ was measured over seven weeks grown under LED and HPS HID lamps. Table 2. The results of effects on plants height of Capsicum annuum ‘Hungarian’ and Bellis perennis ‘Monstrosa’ of grown LED and HPS HID lamps. (Department of Horticultural Science, University of Minnesota)

Figure 7. Curve of plant height of Capsicum annuum ‘Hungarian’ and Bellis perennis

‘Monstrosa’ (Department of Horticultural Science, University of Minnesota) CONCLUSIONS

The LED-based illuminations with a proper proportion of light components enhance photosynthetic productivity and ensure better plant morphology in comparison with illuminations using high pressure sodium lamps. High-power AlInGaP-based red LEDs emitting at wavelengths as close as possible to 660nm as well as further development of LEDs emitting in the vicinity of 640nm are of major interest for horticulture applications.

Today’s plant grow lights are merely an adaptation of yesterday’s warehouse and factory illumination bulbs. Never originally designed to do more than help a person find their way in the dark, the physics of these bulbs are severely limited. In reality plant grow light bulbs are manufactured as imperfect illumination devices. That is, chemicals and gases are added to the bulb to slightly increase light wavelengths

Mean Plant Height (cm) Week No

LED HPS 3 12.7 11.9 4 13.9 13.4 5 15.4 14.9 6 17.1 16.3 7 19.2 18.6

Mean 15.2 13.9

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that are beneficial to plant growth which at the same time render the bulb unacceptable for general lighting.

LED lighting arrays are designed specifically for the application. Light absorption in plants occurs over a wide range of wavelengths, but in greatly varying degrees. LED arrays can target light wavelengths that have high absorption rates for extremely efficient operation. The implementation of LED-based illumination on industrial scale for greenhouse plant cultivation requires lowering of LED prices, what might be achieved by producing LEDs specifically for horticulture applications. Also, it has to be seen how insects in the greenhouse react to LED lighting and its affect on working conditions and safety, for example the human eye, has to be examined.

Another item of research is the efficiency of the LEDs. At the moment the amount of light per watt electricity is still disappointing. The output of a LED is still les than half the output of traditional HPS lamps. Another problem is that while LEDs produce no heat on the front side of the lamp where the light is emitted, a lot of heat is produced at the back of the device. This needs cooling for two reasons; firstly the longevity of the LED decreases when the temperature is higher and secondly the wavelength moves when the LED becomes warm. The cooling devices which are available at the moment are still too big for greenhouse applications.

LED technology is developing rapidly, as the energy efficiency is interesting for many applications, such as traffic lighting, office lighting, road and garden lighting, for car lamps. Nowadays, it seems that LED lamps are used to increase photosynthesis in greenhouses. LED lighting systems in comparison to other lighting systems are an important alternative for greenhouse lighting systems and LED lights will able to provide important advantages for agricultural lighting applications in the future. REFERENCES 1. Ciolkosz, D.E., Both, A.-J., Albright, L.D., 2001. Selection and placement of

greenhouse luminaires for uniformity. Applied Engineering in Agriculture 17 (6), 875–882.

2. Deitzer, G., Langhans, R., Sager, J., Spomer, A., Tibbitts, T., 1994. Guidelines for installation of supplementary lighting in greenhouses. Proceeding of the International Lighting in Controlled Environments Workshop, NASA Publications, Madison, WI, CP95-3309, pp. 391–393.

3. Bubbenheim, D.L., Bugbee, B., Salisbury, F., 1988. Radiation in controlled environments: influence of lamp type and filter material. Journal of the American Society for Horticultural Science 113 (3), 468–474.

4. Albright, L.D., Both, A.-J., 1994. Comparisons of luminaires: efficacies and system design. In: Proceeding of the International Lighting in Controlled Environments Workshop, NASA Publications, Madison, WI, CP95-3309, pp. 281–297.

5. Sager, J.C., 1984. Spectral effects on the growth of lettuce under controlled environment conditions. Acta Horticulture 148, 889–896.

6. Both, A.-J., Albright, L.D., Langhans, R.W., Vinzant, B.G., Walker, P.N., 1997. Electric energy consumption and PPFi output of nine 400w high pressure sodium luminaires and a greenhouse application of the results. Acta Horticulture 418, 195–202.

7. Both, A.J., 2000. Some Thoughts on Supplemental Lighting for Greenhouse Crop Production. Bioresource Engineering Department of Plant Biology and Pathology Rutgers, The State University of New Jersey New Brunswick, NJ 08901-8500

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8. Web page of LGL Technologies Inc, http://www.ledgrowlights.com 9. Web page of Photonics, http://www.photonics.com/Article.aspx?AID=34318 10. Web page of Ledtronics Inc, http://www.ledtronics.com/ 11. Web page of CHEVY LIGHT Co., Ltd., http://www.growlight.cn/ 12. Klaassen, G., McGregor, R., Zimmerman, J., Anderson, N., 2005. LED’s: New

Lighting Alternative for Greenhouses. Department of Horticultural Science, University of Minnesota St. Paul, MN 55108

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Chapter 10

THE INFLUENCE OF MATERIAL HOMOGENEITY ON THE PROCESS

OF FLUIDIZED-BED DRYING OF SHORT ROTATION COPPICE POPLAR

Szymon GŁOWACKI, Mariusz SOJAK INTRODUCTION

Renewable resources of energy make it possible to reduce the emission of greenhouse gases, mainly carbon dioxide [Chochowski, 2001]. The carbon cycle is the fundamental factor linking biological life with the transformation of inanimate matter. It is in balance when CO2 emission is equal to the adsorptive capacity of green plants. The balance of CO2, which is obtained as a result of biomass burning, is assumed to be equal zero as it is reused in the photosynthesis process [Dubas, 2004]. At present, one of the most important renewable energy sources is biomass. In order to use biomass as fuel, it is necessary to prepare it for the process of combustion [Kowalik, 2003. Energy efficiency and ecological efficiency of the combustion or gasification process depend on the construction of the boiler, the combustion gas disposal installation and the quality of fuel. Relative humidity and impurities are the two main factors that influence the quality of biomass fuel [Gradziuk, 2003]. The biomass fuel value depends on humidity. The lower the humidity the less energy is used to evaporate water, which increases the efficiency of the combustion process. Therefore, the fundamental process in the biomass processing is drying in order to decrease the humidity to the level that makes further technological processes possible.

Drying technology is a continually developing field of knowledge. New plants with high biomass increment (e.g. 12 t/ha) grown to be used as fuel are called ‘short rotation coppice’ plants. Preparation and use of plants for production of large amounts of energy (e.g. 10 MW) both electrical and heat energy is poses many technological problems. It is a new, developing field of knowledge in Poland. Short rotation coppice trees include willow (Salix viminalis), poplar (Populus tremula), and locust (Robinia pseudoacacia) [Kościk, 2003]. Drying is a complicated technological process which should not only preserve the properties of the material but also improve these properties. Therefore, solving problems connected with drying

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technology should be based on scientific principles of drying technology: starting with the properties of the material - the material undergoing the process of drying, through the selection of drying methods, the course of the process and finishing with the design and construction of drying equipment. Agricultural drying has its characteristic technical-economic features which influence the range of applications and are of primary importance as regards technical solutions. Convective drying is a physical process in which the drying factor (usually the stream of air), which circulates round the dried material is responsible for heat supply and humidity disposal. [Pabis, 1982]. RESEARCH GOAL

The goal of the research was to show the influence of the homogeneity of the size of wood chips (biomass) on the fluidized-bed process of drying. RESEARCH METHODOLOGY

The research was conducted in the Drying Laboratory, Division of Technical Sciences Fundamentals, Department of Fundamental Engineering, Warsaw University of Life Sciences (SGGW).

3-year-old trembling poplar (aspen) (Populus Tremula) was used in the experiments.

Poplar has been used as a renewable energy resource for many years. Trembling poplar is a dioecious tree. It grows up to heights of 30-35 metres and its breast height diameter is up to 1m. The wood is homogeneous, smooth, white with greenish tint, it is light and soft, uniform-porous. Sapwood (alburnum) and heartwood (duramen) cannot be distinguished. Aspen vast range resulted in the formation of numerous ecotypes, which differ in many respects. Aspen in Poland has not been examined in detail. Its numbers have decreased considerably in the last few years. Earlier, aspen was treated as a ‘parasite’ among trees, it was removed from forests or used without taking care of the reforestation.

Aspen is characterized by considerable morphological and physiological changeability. Numerous species were distinguished, which differ in respect of shape and size of leaves, bark hue and habit, as well as the resistance to fungi in the same habitat.

This tree grows very fast in the first years. One-year old seedlings can grow up to the height of 20 – 60cm, two-year-old ones – up to 2m. 15-year old trees grow up to the height of 15 metres. Its longevity is up to 100 but trees that are 50-60 years old stop to grow higher.

It is used in match industry for the production of cellulose, artificial fibre, household equipment, shingles and for many other purposes. Therefore, recently, aspen has become more and more valuable [www.encyklopedjaleśna.pl].

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Figure 1. Plantation poplar

Source: www.rolnicze24.pl/mazowieckie/energia-odnawialna/brykieciarki/rosliny-energetyczne-topola-energetyczna.html

Aspen is a Eurasian species, with vast geographical range. The range of

aspen extends from Northern Africa to Northern Europe (70° northern latitude) and from Western Europe to Eastern Asia. It can be found high in the mountains above the beech range, in the Alps it can be found up to 1530 metres above the sea level, in the Karkonosze - up to 1250 metres above the sea level, in the Carpathians - up to 1150 metres above the sea level, and in the Tatras - up to 1425 metres above the sea level. In the south, aspen can be found almost exclusively in the mountains. The conditions in the Baltic States and in the European part of Russia are most favourable for aspen. It extends furthest in the steppe, further than other trees, where shrub-like forms of aspen can be found [www.encyklopedjalesna.pl].

It has moderate soil and humidity requirements. It is the least demanding of all poplar species. It grows on dry, rocky soils, with sandy subsoil. However, it dies in wetland areas. It requires a lot of sunlight, and it is tolerant of high and low temperatures. It regenerates well after fires and harvesting. It can often be found as a subdominant in coniferous and deciduous forests.

The poplar used for the purpose of the experiment had a diameter of 3 cm. The material was dried in the form of chips.

Due to the differences in the size of the chips, the material was sieved using a screen separator owned by the Farm Machines Unit (fig. 2).

Figure 2. Screen separator

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As a result of sieving, chips were divided into six categories (fractions) (table 1). Table1. Characteristic data of the separator’s sieves and the weight of sorted chips on the sieves

Number of sieve

The dimension of the square opening, mm

The diagonal of the square opening, mm

Poplar weight, (g)

1 19 26.9 465.9

2 12.7 18 3109

3 6.3 8.98 12460

4 3.96 5.61 6010.5

5 1.17 1.65 4190.5

6 (bottom)

- - 693.4

Total 26929.3

Fig. 3 presents the distribution of weight of the sorted (sieved) material. As it can be seen (fig. 3), the material that remained on sieve 3 is heaviest.

465,9

3109

12460

693,4

4190,5

6010,5

0

2000

4000

6000

8000

10000

12000

14000

1 2 3 4 5 6

Nr sita

Ma

sa

(g

)

Figure 3. The distribution of the material sieved by the separator

Poplar chips, used for the experiment, were sieved to obtain chips of the same

size, with the sizes depending on the openings in the sieves. The homogeneity is presented in fig 4.

Number of sieve

we

igh

t (g

)

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Figure 4. Chips used in the experiment after sieving

Due to the fact that the drying process involved forced air circulation, samples

with numbers 2 (large), 3(medium) and 4 (small) were used in the experiment. Other fractions were not used due to their dimensions, which would either block the fluidizing movement of the material (number 1) or cause the material to be lifted above and out of the fluidized-bed drier (numbers 5 and 6). The process of drying was conducted in the laboratory fluidized-bed drier, in which it was possible to regulate both the temperature and the speed of the drying factor (fig. 5a).

The experiments were conducted at the following 5 temperatures of the drying factor: 40, 50, 60, 70 and 80°C for 4 fractions of the chips. a b

Figure 5. a) Fluidized-bed drier, b) Fluidization of the chips during drying

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The laboratory drier consisted of: • motor, • fan, • control panel, • heater, • drying chamber.

MEASUREMENTS RESULTS

The measurements results were presented in the form of the dependence of water content on the drying time and temperature, in individual media also on the duration of the process. Water content in sample u(τ) was calculated using the following formula:

( )( ) ( )

s

s

sM

MM

M

Wu

−

==

ττ

τ ,

..

2

mskg

OHkg (1)

where: W(t) – water content in the sample during drying [kg], M(t) – sample weight after drying [min], Ms – weight of dry sample [kg].

The following figures present selected results of the experiments graphically:

Figure 6. Change in the content of water during fluidized-bed drying of unsorted poplar chips

The analysis of the graphs illustrating changes of water content for the

unsorted chips shows that for the samples dried at temperatures 40, 50 and 60°C final water content equal approximately 0.1 kg/kg was obtained after 180 minutes. This water content may not be treated as the equilibrium water content for these temperatures. For the samples dried at the temperature 70°C and 80°C, the equilibrium water content was obtained after 130 and 50 minutes of drying

0 15 30 45 60 75 90 105 120 135 150 165 180 195

Czas suszenia, min

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

Za

wa

rto

wod

y,

kg

/kg

Fluidyzacja topoli

80 C

70 C

60 C

50 C

40 C

drying time, min

wa

ter

con

ten

t, k

g/k

g

Fluidization poplar

111

respectively. The conducted experiment clearly shows the temperature range in the examined samples. The change of temperature from 40 to 80°C considerably shortened the drying time of poplar. The time was shortened by more than 150 minutes.

0 30 60 90 120 150

Czas suszenia, min

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

1.30

1.40

Za

wa

rto

ść w

od

y, kg

/kg

Duże zrębki

40 C

50 C

60 C

70 C

80 C

Figure 7. Change in the content of water during fluidized-bed drying of large poplar chips

In comparison to unsorted chips, the process of drying large, sorted chips was more uniform. Water content equal approximately 0.1 kg/kg in chips dried at temperature 40°C was obtained after 150 minutes. It was the longest observed time in comparison with other variants of the process. During drying at temperatures of 60, 70 and 80°C the changes of water content in time were similar. These samples were dried to the equilibrium water content equal approximately 0.03 kg/kg.

drying time, min

wa

ter

con

ten

t, k

g/k

g

Large chips

112

0 30 60 90 120

Czas suszenia, min

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

1.30

1.40

Zaw

art

ość w

od

y,

kg

/kg

Średnie zrębki

40 C

50 C

60 C

70 C

80 C

Figure 8. Change in the content of water during fluidized-bed drying of medium poplar chips

During fluidized-bed drying of medium poplar chips it is possible to notice a certain uniformity of drying of samples dried at temperatures of 60, 70 and 80°C. For all examined samples the equilibrium water content was obtained, regardless of the drying temperature. The duration of the process was also shortened for each temperature.

drying time, min

wa

ter

con

ten

t, k

g/k

g

Medium chips

113

0 30 60 90

Czas suszenia, min

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

1.30

1.40

Zaw

art

ość w

ody, kg/k

g

Małe zrebki

40 C

50 C

60 C

70 C

80 C

Figure 9. Change in the content of water during fluidized-bed drying of small poplar chips

The analysis of small chips samples dried at lower temperatures and the sample dried at the temperature of 80°C shows that the equilibrium water content in these samples differ considerably. The difference in the final water content for the samples dried at the temperatures of 40, 50, 60 and 70°C is small and it is equal 0.05 kg/kg. In comparison to other fractions of poplar, small chips dried in a considerably shorter period of time. It took about 40 minutes to complete the process. CONCLUSIONS

1. The experiments confirmed that the rise in the temperature of the drying factor

shortens drying time for all the examined variants of the experiment 2. Sorting the material considerably shortened drying time in comparison with the

unsorted material. This difference equalled approximately 60 minutes for large chips, 100 minutes for medium chips and 150 minutes for small chips.

3. There was also a difference in the length of drying time for different fractions of poplar chips. It took the longest to dry large chips. Medium chips took shorter to dry, and drying time for small chips was shortest.

4. Equilibrium water content equal approx. 0.03 kg/kg for medium chips was obtained for each temperature of the drying factor.

5. Further research concerning drying of wood biomass allowing to make mathematical models of the drying process is necessary.

REFERENCES

1. Chochowski A. Techniczne ekologiczne i ekonomiczne aspekty energetyki odnawialnej , Wyd. SGGW, 2001

2. Dubas J.W., Co to są rośliny energetyczne? Wieś Jutra nr 8-9, 2004

drying time, min

wa

ter

con

ten

t, k

g/k

g

Small chips

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3. Gradziuk P.: Biopaliwa. Wydawnictwo Wieś Jutra, Warszawa, 2003 4. Kościk B.: Rośliny energetyczne. Wydawnictwo Akademii Rolniczej w Lublinie,

Lublin 2003 5. Kowalik P.: Perspektywy paletyzacji biomasy w Polsce. Gospodarka Paliwami i

Energią. 5/6 2003 6. Pabis S., Teoria konwekcyjnego suszenia produktów rolniczych. PWRiL,

Warszawa. 1982 7. www.encyklopedjalesna.pl 8. www.rolnicze24.pl/mazowieckie/energia-odnawialna/brykieciarki/rosliny-

energetyczne-topola-energetyczna.html