2nd International Conference on Electronic & Mechanical Engineering and Information Technology (EMEIT-2012)

Transcription

1 2nd Interntionl Conference on Electronic & Mechnicl Engineering nd Informtion Technology (EMEIT-2012) Comprehensive Evlution of Air Conditioning Cold/Het Source System Bsed on Fuzzy Mthemtics Theory Gng Chen 1,, Jiping Xie 2,b, Huimin Li 3,c, Xin Cheng 4,d 1,2,3,4 University Of South Chin,Hengyng, Hunn, Chin b Keywords: Air Conditioning Cold/Het Source Systems, Fuzzy Mthemtics Theory, Fuzzy Comprehensive Evlution Abstrct. This rticle use fuzzy comprehensive evlution to quntittive nlysis ech fctor which effect the selection of ir conditioning cold/het source systems. Menwhile, offer resonble nd fesible method to ir conditioning cold/het source system selection through concrete exmple. Introduction There re mny effect fctors to ir conditioning system selection, so its hrd to mke resonble evlution to n ir conditioning cold/het source system. At present, it minly rely on experts judgement which hs its boundedness. First, the ccurcy is bsed on the experts' structure of knowledge nd prcticl experience; second, its hs strong subjectivity; the most importnt is tht the expert review will tke long time nd much money nd hrd to extend in medium nd smll project. Every yer, medium nd smll projects tke lrge rte in chin, so find resonble evlution methodology for the ir conditioning cold/het source system hs importnt significnce to reduce ir conditioning system energy consumption nd stndrd ir conditioning industry. Fuzzy Mthemtics Theory Fuzzy Mthemtics Theory Fuzzy mthemtics theory ws put forwrd by Americn fmous computer nd control experts professor L.A.Zdeh in 1965 [1]. Fuzzy mthemtics is mthemtic theory nd method to reserch nd dispose fuzziness phenomenon, people use concept to judge, evlute, inference, decision nd control qulittive process which cn use fuzzy mthemtics theory turn it to quntittive process. This rticle use this method to quntittive tret ech fctor which effect the ir conditioning cold/het source system selection, nd use fuzzy comprehensive evlution [2] to sorting the reserch object in fuzzy environment or fuzzy system, to pick out the optiml objects from decision discourse ccording to some fuzzy constrints. Procedure of Fuzzy Comprehensive Evlution Fuzzy comprehensive evlution is kind of method which use the theory of fuzzy reltion synthesis nd use mny fctors to comprehensive evlution be-evluted objects membership grde condition, its specific steps re: 1) Determine be-evluted objects fctor theory field U, U= ( u 1,u 2,u 3, un) ; 2) Determine comment grde theory field V, V = ( v1, v2, v2, vn ). Usully, comment grde V =( highest, higher, high,, low, lower, lowest); 3) Single fctor evlution, build fuzzy reltion mtrix R: R r11 r12 r1 m r r r rn1 rn2 rnm m = r is the subjection reltion for fctor u i to grde v i ; 0 r 1 (1-1) Published by Atlntis Press, Pris, Frnce. the uthors 0905

2 2nd Interntionl Conference on Electronic & Mechnicl Engineering nd Informtion Technology (EMEIT-2012) 4) Determine judging fctor weight vector A ( ) = 1, 2, 3, n, A is the subjection reltion for the fctors of U nd be-evluted objects, which depend on the vntge point of people when mke fuzzy comprehensive evlution. 5) Choose co mposition opertor B = ( b1, b2, b3, bm ), combine A nd R to get r11 r12 r1 m r21 r22 r2 m B AOR ( 1, 2,, n ) O = = (1-2) rn1 rn2 rnm bj = ( 1 r1j) + ( 2 r2 j) + + ( n rnj) (1-3) mong it, j=1,2,,m 6) Choose n optiml results of b j ccording to the fuzzy constrints. Use Fuzzy Mthemtics Theory to Anlysis Cse of Air Conditioning Cold/Het Source System Selection This rticle use cse of ir conditioning cold/het source system selection for exmple, use fuzzy mthemtics theory to finlistion the ir conditioning cold/het source system of the project. Project profile This exmple is n ir conditioning project for cosmetic medicl orgniztion, nd only need to design ir conditioning system on work re nd inptient deprtment for the sk of the first prt. Overll floorge is 5300m 2, mong them, ir conditioning use re is 3800m 2, totl ir conditioning cooling lod is 490KW, heting lod is 300KW. According to its cold nd hot lod, intends to use three cold nd het source scheme s follows tble 1. tble 1 Scheme Scheme one Scheme two Scheme three Cold nd het source shpe Totl refrigerting cpcity/heting cpcity(kw) The number of mchine Totl refrigerting power (KW) Totl heting power (KW) Remrks Wter Source Het Pump Air-cooled het pump module nd Electric booster heter Wter cooled screw unit nd Boiler 515/ / Choose 300,000 kiloclorie boiler for heting in winter The choose of evlution index for ir conditioning cold/het source system There re mny influencing fctors for the choose of ir conditioning cold/het source system, which mong quntittive fctors nd qulittive fctors, the completeness nd rtionlity is the premise to judge the qulity of ir conditioning cold/het source system. This rticle comprehensive evlution it from first cost u 1, yer operting cost u 2, service life of ir conditioning cold/het source system u 3, yers costs of opertion nd mintennce u 4, life cycle cost u 5, opertionl stbility u 6, construction conditions nd construction period u 7, environment-protected nd energy-sving chrcter u 8. Among them, u 1, u 2, u 3, u 4 re quntittive fctors while u 5, u 6, u 7, u 8 re qulittive fctors. Published by Atlntis Press, Pris, Frnce. the uthors 0906

3 2nd Interntionl Conference on Electronic & Mechnicl Engineering nd Informtion Technology (EMEIT-2012) Determine index of quntittive ssessment 1) Determine first cost u 1 This rticle only tke cold nd het source system cost s centrl ir conditioning cold/het source system's first cost. 2) Determine yer operting cost u 2 Yer operting cost is clculte by the ctully cooling nd heting period of the project city nd the price of electricity nd gs. In this rticle, cooling nd heting period ll design s120 dys, 8 hours dy, electricity price is 1.2 yun per kwh, gs price is 2.5 yun per m 3. 3) Determine service life of ir conditioning cold/het source system u 3, yers costs of opertion nd mintennce u 4 Service life of ir conditioning cold/het source system nd yers costs of opertion nd mintennce re determined by the recommendtion of hndbooks [3][4] nd mnufcturers dt. Yers costs of opertion nd mintennce is clculte s the verge nnul cost of 12-yers-service life system ( minor repir when the refrigertion compressor runs hours, medium repir when it runs hours). 4) Determine life cycle cost (LCC) u 5 LCC is response bout first cost nd yer operting cost, nd is n importnt index to overll considertion first cost nd operting cost [5]. Ech quntittive evlution index is shown in the following tble 2 tble 2 Quntittive evlution index Scheme one Scheme two Scheme three First cost u 1 (ten thousnd yun) Yer operting cost u 2 (ten thousnd yun) Service life of ir conditioning cold/het source system u 3 (yer) Yers costs of opertion nd mintennce u 4 (ten thousnd yun) Life cycle cost (LCC) u Determine qulittive evlution index 1) Determine opertionl stbility u 6 Wter source het pump nd ir-cooled module unit use "free" energy from groundwter or ir, while wter cooled screw unit nd boiler rely on cooling tower to dischrge het of condenstion in summer nd gs-heting in winter. Groundwter temperture remin stble below certin depth, while ir temperture nd reltive humidity chnge lrgely with seson, which mke the performnce stbility of ir-cooled module nd wter cooled screw unit not s good s wter source het pump. At winter heting period, boiler heting is stbiler thn ir-cooled module. For this reson, opertionl stbility of ech scheme is like follow. Scheme one is "Good", scheme two is "Bd", nd scheme three is "Common". 2) Determine construction conditions nd construction period u 7 Consider mny uncertin fctors in relity project, this rticle overll consider construction period s qulittive fctors. Wter source het pump is gret difficulty becuse it need to dig well, wter cooled screw unit nd boiler need instll cooling tower nd boiler. So, the construction conditions nd construction period is s follow. Scheme one is "Long", scheme two is " Short", nd scheme three is "Common". 3) Determine environment-protected nd energy-sving chrcter u 8 Het bsorb nd het relese of wter source het pump system re underground, it will cuse certin therml pollution to underground environment for long run. While ir-cooled het pump module bsorb nd relese het to ir nd will cuse locl environment cold or het pollution, wter cooled screw unit nd boiler unit set wste het nd humidity to ir in summer, nd set gseous pollutnt in winter. According to environment evlution index to get the evlution result s: cheme one is "Good", scheme two is " Bd", nd scheme three is "Common". Published by Atlntis Press, Pris, Frnce. the uthors 0907

4 2nd Interntionl Conference on Electronic & Mechnicl Engineering nd Informtion Technology (EMEIT-2012) Determine quntittive membership degree We choose the mximum v nd minimum v s the up nd down limit of this rticle's quntittive membership degree [2]. Ech membership degree eqution is s follow. For the objective which is optiml when the number lrger. v = (2-1) mx v ( ) For the objective which is optiml when the number smller. min( v ) = 1 (2-2) v Among the eqution, r The number i evlute object quntittive membership degree of ir conditioning cold/het source system solutions j. Determine qulittive membership degree According to section 2.4 nd expert evlution method, we cn mke sure the qulittive membership degree for those cnnot use function of quntittive membership degree. This rticle use 5 grde to contrst the Strengths nd weknesses of ech object. The 5 grde re: better, good, common, bd, worse.the intervl of such grde is [0,1]. Expert evlution method is N experts quntittive evlution ccording to themselves cognition to ech qulittive index nd tke its rithmetic men vlue. The eqution is: x k = (2-3) n Among the eqution, x k The number N expert's quntittive evlution vlue to number j scheme's number i qulittive evlution index. The lrger r is, the object is more optiml. According to quntittive nd qulittive membership degree evlutionl principle, we cn get ech scheme's membership degree of different influencing fctors s follow tble 3. Tble 3 Quntittive index Scheme one Scheme two Scheme three First cost u 1 (ten thousnd yun) Yer operting cost u 2 (ten thousnd yun) Service life of ir conditioning cold/het source system u 3 (yer) Yers costs of opertion nd mintennce u 4 (ten thousnd yun) Life cycle cost (LCC) u Opertionl stbility u Construction conditions nd construction period u Environment-protected nd energy-sving chrcter u System fesibility u Determine weight vector A The certinty principle of weight vector A [2] is dopt to experts nd building side evlution method, nd use eqution 2-3 to clculte. According to eqution 2-3 to clculte weight vector A: A = ( ) A=( ) Evlution result Set evlution synthetic opertor s B, fuzzy reltion mtrix is Published by Atlntis Press, Pris, Frnce. the uthors 0908

5 2nd Interntionl Conference on Electronic & Mechnicl Engineering nd Informtion Technology (EMEIT-2012) r11 r12 r1 m r21 r22 r2 m R = = , rn1 rn2 rnm x11 x12 x1 m x21 x22 x2m Then, B =[ b 1, b 2, b3 ]=A*R=[ ] =[0.36 xn1 xn2 xnm 4, 0.380, 0.553] From the evlution result cn see tht b 3 > b2 > b1, which cn intuitive get tht scheme three is better thn scheme two, scheme two is better thn scheme one. So dvice building side choose scheme three s finl project. Conclusion Use fuzzy mthemtics theory to evlute ir conditioning cold/het source system cn not only mke the evlution result more visul but cn lso fully reflect the influence degree to the system of ech fctors. This rticle nlysis to give concrete exmple fesible method to the selection of ir conditioning cold/het sources system design. References [1] Zdeh. Fuzzy Sets[J]. Informtion nd Control,1965,8: [2] Jin Xie. The Theory nd Appliction of Fuzzy Mthemtics (Second Edition) [M]. Wuhn. HUST Press [3] Zuiling M, Yng Yo.Civil Design Mnul [M]. Being. Chemicl Industry Press [4] Yoqing Lu. Heting Air Condition Design Hndbook [M]. Being. Chin Building Industry Press [5] Yi.Jing.Building Energy Efficiency Technology nd Appliction[M]. Being. Chin Building Industry Press Published by Atlntis Press, Pris, Frnce. the uthors 0909