7/28/2019 05448519

1/4

Value Engineering for Selection of Gas Sources in

Gas Supply Engineering

Liu JiayouDepartment of resources and civil engineering

Shandong University of Science and Technology

Taian, China

E-mail: liu_jiayou@163.com

AbstractApplying an appropriate city gas source is important

for reducing the costs of living and production, energy-saving,

environmental protection and city long-term planning. According

to the principle of value engineering (VE), the paper puts

forward a model for selecting city gas source. The model includes

identifying research object, function analysis, cost analysis and

value analysis. The model mainly focuses on function analysisand a functional evaluation index system of gas source is

constituted, the improved analytical hierarchy process (AHP) is

used to determine the weights of the indexes for function

coefficient calculation. Combining the technical and economic

characters of gas sources, value index is formulated as the

evaluation parameter to select the optimal scheme. An

application case is studied using the model, and the selected gas

source long-distance pipeline natural gas (LPNG) is suitable for

the city.

Keywords-value engineering; gas source; function analysis;

value index

I. INTRODUCTIONCity gas is one of the most important energy resources for

urban residents living and industry production. An appropriategas source is of significant for reducing the costs of living and

production, energy-saving, environmental protection andpromoting sustainable development of cities. At present, citygas sources mainly include LPNG, liquefied natural gas(LNG), compressed natural gas (CNG), liquefied petroleumgas (LPG), manufactured gas (MG) (including coal-generatedgas, oil-generated gas, etc) [1]. And marsh gas is used as gassource in some small towns. Because of differentcharacteristics of gas sources and diversity of cites locationand long-term planning, many factors should be considered

when selecting gas source. In gas supply engineering, thecommon method for selecting gas source is that thecharacteristics of the gas sources and city gas pipeline planningare qualitatively analyzed, and then the optimal gas source isdetermined by comparing the annual cost of gas sources

projects. The method is more subjective and evaluation index issimplex [2]. The paper presents a model based on VE forselecting optimal city gas source.

II. MODEL FORSELECTING CITY GAS SOURCE BASED ONVE

A. Principle of VEVE or value analysis (VA) is a scientific techno-economic

comparison method developed by Lawrence D. Miles. Themethod uses all existing technologies, knowledge, and skills toefficiently identify costs or efforts that do not contribute to thecustomer's needs and wants [3]. VE focuses on functionanalysis of the research objects and aims to gain the maximum

benefits and the needed functions at the lowest life cycle cost(LCC). The expression for the method is (1).

CFV /= (1)

Where, V is value or value index of the scheme, F is the

function or function coefficient of the scheme, C is cost orcost coefficient of the scheme.

To gain the maximum benefits, F should be greater andC should be smaller. A greatest value of V shows thefunctions of the research object are achieved at the lowest LCCand the object should be the optimal one.

B. Model for Selection of Gas Sourcse in Gas SupplyEngineering

The program of VE includes identifying research object,function analysis, cost analysis and value analysis.

1) Determining research objectTo select the optimal city gas source using VE method,

various gas sources should be identified as the research objects

[3].

2) Function analysisCity gas source takes the role of supplying gas for varioususers safely and reliably, the characteristics of gas sources mustmeet the requirements of different users and the requirementsof city long-term planning, the design and construction of gassource engineering must follow the relevant norms andregulations and strive to reduce the project cost. According tothe suggestion of experts and gas engineering requirements, thefunctional evaluation index system of gas source is constructedand shown in Fig.1.

978-1-4244-4813-5/10/$25.00 2010 IEEE

7/28/2019 05448519

2/4

The importance of the evaluation indexes in Fig.1 isdifferent, it is necessary to determine the weights of the indexesfor calculation of function or function coefficient. In the paper,the weights are determined using improved AHP. Assumingm experts evaluate the importance of n indexes on the samelayer. According to the principle of AHP, a judgment matrix is

established, then an eigenvalue weight matrixB can be gainedusing the concept of the optimal delivery matrix of

antisymmetric matrix [4], [5], [6].

==

mnmm

n

n

nm

bbb

bbb

bbb

BB

"

####

"

"

21

22221

11211

)( (2)

10 kjb , 11

==

n

j

kjb , ( )njmk ,,2,1;,,2,1 "" ==

Where, kjb is the weight of the j index evaluated by the

k expert.Objectively, there is an optimal relative weight matrix

( )nwwwW ",, 21= and it can be obtained using conceptof generalized distance and the minimum variance.

( )= =

==

m

k

n

j

jkj wbWBD1 1

22

Seeking derivative of the variable jw , letting

02211

==

==

m

k

kj

m

k

j

j

bww

D

m

b

w

m

k

kj

j

==

1 ( )nj ,,2,1 "= (3)

( )

( )

2/1

1 1

2

1

2

=

= =

=

m

k

n

j

jkj

n

j

jkj

k

wb

wb

c (4)

Where, kc is the proportion of weight error evaluated by

the k expert to the total weight errors. According to the

principle that the smaller is the error, the larger is the entropy,the following transformation is carried out.

kk cd /1= (5)

Figure 1. Functional evaluation index system of gas source.

=

=m

k

k

kk

d

d

1

(6)

So the comprehensive weights matrix V of the indexescan be expressed as (7).

nj vvvvBV "" ,,,, 21== (7)

( )m ,,, 21 "=

Where, jv is the comprehensive weight of the j index.Five experts are invited to evaluate the indexes in Fig.1

using the improved AHP. The weights of the indexes arecalculated and shown in TABLE I and TABLE II.

According to functional evaluation index system of gas

source, the indexes are graded using 10-points system, and a

high score shows the degree satisfying the basic function is

higher. Assuming there are p schemes and q function

indexes, the cumulative scores of the indexes and function

coefficients can be calculated using (8) and (9) respectively.

ij

q

j

ji SvS =

=1

( )pi ,,2,1 "= (8)

TABLE I. INDEX WEIGHT OF BLAYER

Index B1 B2 B3

Weight 0.6056 0.1972 0.1972

TABLE II. INDEX WEIGHT OF CLAYER

B B1 B2 B3

Index C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12

Weight 0.2784 0.2666 0.2750 0.1122 0.0679 0.4437 0.1850 0.1629 0.5296 0.0739 0.2024 0.1942

7/28/2019 05448519

3/4

7/28/2019 05448519

4/4

Annual cost, 104yuan 169 240 336 177

Cost coefficient 0.1835 0.2606 0.3637 0.1922

TABLE V. VALUE INDEXES OF GAS SOURCES

Item LPNG LNG CNG LPG

Function coefficient 0.2674 0.2508 0.2493 0.2324

Cost coefficient 0.1835 0.2606 0.3637 0.1922

Value index 1.4572 0.9624 0.6855 1.2092

IV. CONCLUSIONAccording to principle of value engineering, a model for

selection of city gas sources is constructed. The model mainly

focuses on the function analysis of city gas source and a

function evaluation indexes system for gas sources isestablished, an improved AHP are used to determine the

weights of the indexes. Value indexes of gas sources are used

as the evaluation parameter for selection of gas sources.Application case is analyzed using the model and the

selected gas source LPNG meets the city requirements. Valueengineering is feasible to select the city gas source and theevaluation result is reasonable and intuitive.

REFERENCES

[1] Duan Changgui, Gas Transmission and Distribution, Beijing: ChinaArchitecture & Building Press, 2002.

[2] Deng Yuan, Handbook of Gas Planning and Design, Beijing: ChinaArchitecture & Building Press, 1992.

[3] MILES L D., Techniques of Value analysis and Engineering. NewYork: McGraw-Hill,1972.

[4] Yang Hong and Wan Zhonglun, Determination of the function weightin value engineering, Journal of Xihua University (Natural Science),Vol.24, pp.77-79, March 2005.

[5] Jia-you LIU, Selection of gas pipeline system schemes based on valueengineering, Proceeding of the 2nd International Conference on ValueEngineering and Value Management (ICVE&M2009), PublishingHouse of Electronics Industry, pp. 227-232, October 2009.

[6] Ma Rongguo and LiuYanni, Weight value determination method ofhighway construction comprehensive evaluation, Journal of Trafficand Transportation Engineering, vol. 5, pp.110-112, June 2005.

[7] Liu Jiashun, Li Guoming, Technology Economy, Beijing: MechanicIndustry Press, 2004.

[8] Sun Jihong, Gas source selection for middle and small cities,Engineering Construction and Archives, vol.19, pp.417-419, May 2005.

[9] Yang Jianwei and Zhao Liang, Selection of city pipeline reserve gassource, Urban Gas, vol. 372, pp.25-26, February 2006.

[10] Xu Shu, Economic and technical analysis of gas source selection inXinglin region, Energy and Environment, pp.27-30, March 2004.

[11] FU Xiguo, Selection of gas sources in middle and small towns, GAS& HEAT, vol. 25, pp.7-48, July 2005.