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Curs Instalatii 01.04.2014

If a building has several floors and several types of rooms, fresh air prepared for whole building

in specialized equipments is sent to each room through channels mounted in false ceilings, where it can

be also mounted heat pipes, drinking water pipes and so on. Specialized equipment has several parts

which filter, humidify, dry, heat or cool air. Fans are dimensioned according to building size and can be

axial type or radial type. Air can be filtered in different types of cells which can be constructed with

paper, textile material, and metallic mesh and so on.

In the cells of rotating recoverer the heat is retained and transmitted to the fresh air entering

the system. The cells are usually made from ceramic material which can accumulate easily the heat

transported. *poza 1

If the cells are covered with hydroscopic solution the excess of humidity from polluted air is also

removed. For adjusting the air flow there can be used different type of apparatus. Conditioned air canalso humidify fresh air or contrary if it necessary as drying cells. *poza 2

In summer time we have an installation that can cool air; it has the general parts of general

ventilation for air. Supplementary it has a cooling and heating coil. In summer when temp is over 30

degrees the uncomfortable sensation is made especially by humidity that is why it is very important for

air conditioning installation besides cooling the air to dry it. Humid air is passed through an evaporator

which contains very cold refrigerator and humidity contained in air is frozen. Each hour for example an

electric resistance heats the evaporator and freeze is transformed again in water and it can be

evacuated. *poza 3

Hot humid air enters the dehumidifier, humidity is exhausted and the air is dried. The

dehumidifier is a classical heat pump. *poza 4.

Local Cooling and conditioning air could be a window apparatus which is mounted in a wall

whole and is a classic heat pump. It has a refrigerator which in evaporator transforms in vapor, this

transformation is heat consuming and cooled air is circulated with the apparatus fan. The vapor are

compressed in compressor, pass through condenser in the reducer and the cycle is done again. *poza 5

{aparatul de fereastra}.

This type of apparatus has a disadvantage; the noise made by the motor of the compressor is

transmitted to the room. That is why the most used apparatus for cooling air is split system which has an

internal and external unit. *poza 6

It is very important to change every season the filter of the apparatus, which can accumulate

harmful bacteria. If conditioned air is centralized prepared, in the room there could be mounted on the

wall or ceiling a ventiloconvector which can heat or cool internal air according to the season and the

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agent that passed through internal battery of the ventiloconvector. From ventiloconvector could be

transmitted prepared air by vertical currents or horizontal currents according to the mounting system of

the ventiloconvector. A specific type of installation that is energy saving is air curtains which could have

single of double jet of heated air this air curtain replaces successfully the doors of very visited stores or

other buildings. * poza 7

Ventilation systems for swimming pools. *poza 8.

ELECTRIC ENERGY PRODUCTION AND DISTRIBUTION.

Electric energy is produced in thermoelectric stations, hydroelectric stations, nuclear electric

station or wind electric stations. Electric generator produces electric energy at 6kV or 10kV. These

electric generators use mechanical energy for driving, and this mechanical energy could be steam

energy, hydro energy, nuclear and so on. Near power stations the electric energy is transported to rising

transformers, which transform electric energy in order to be transported and rises electric voltage, until

110 kV, 220kV, 380kV.The electric voltage is raised because during transported the losses are much

reduced when electric voltage is high. The higher the electric voltage is the lower electric energy losses

are registered.

Electric energy of high voltage is transported through aerial lines to main cities. In specific

electric stations there are electric transformers in which the voltage is reduced again to 35kV, 20kV or

10kV. With this voltage electric energy is distributed to principal consumers and industrial consumers.

For domestic consumers is reduced to 380V and with this voltage it is distributed to eachbuilding. The buildings are connected to distribution network with electric cables which are accorded to

electric power installed for domestic consumers. The panel after the connection with the distribution

network is named general distribution panel and has for each circuit security systems with fuses

insurance. Each individual domestic consumer is connected to circuits having 230V and if the sum of the

consumers is over 35kV they are connected to 380V. *Poza 9

From the general panel for each floor of the building there are cables distributed and for each

floor we have similar distribution panel named principal panel. From this principal panel each individual

consumer is connected by secondary panels. Between principal and secondary panels is designed to be

mounted the apparatus which measures the amount of electric energy consumed. *Poza 10. (TG- tablougeneral, TPtablou principal, TStablou secundar);

Each secondary panel has different circuit for power consumer and for lighting consumers

(circuite separate pt prize si lumini). Each circuit is assured with specific apparatus against short circuit

or overload. Some main characteristics: electric cables/wire are distributed in building in general

embedded in walls, protected with protection tubes constructed from plastic material or metallic. If it is

not possible to choose separated distribution places especially horizontal ones, electric cables are

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mounted over drinking water pipes or sewage pipes and under hot water domestic pipes and lateral to

gas distribution system. Electric installations are designed only authorized persons, in order to avoid

many problems which can arise if electric installation design is not properly made.