Selection of Thermal Insulation Thickness of Cold Store Enclosures

Transcription

1 ISSN -77 (Paper ISSN -87 (Ole Vol.4, No.5, 3 Selecto of Termal Isulato Tckess of old Store Eclosures Jead Al-Radaede * Bassam Al-goul Muamad Freat 3. Al-uso Uversty ollege, Al-Balqa Appled Uversty, P.O box 5, Aluso 5, Jorda. Al-uso Uversty ollege, Al-Balqa Appled Uversty, P.O box 5, Aluso 5, Jorda 3. Al-uso Uversty ollege, Al-Balqa Appled Uversty, P.O box 5, Aluso 5, Jorda *E-mal of te correspodg autor: adam.bragm@mal.ru Abstract Ts paper ams to set a mecasm order to calculate te ecoomcal tckess of termal sulato layer of exteral walls of cold storage plat based o a compreesve teco-ecoomc aalyss of termal sulato cost, addto to te cost related to te producto of ecessary refrgerato to compesate for eat flow troug te exteror walls to te cold storage ad coservato plat. Some researc tat dealt wt ts topc provded teco-ecoomc aalyss for te cost of termal sulato ad te producto of refrgerato based o exteror walls area of te cold storage plat, wc does ot make sese, ad tat t s dffcult to determe te effect of te operatoal expeses. Terefore, te preset study stems from te dea tat te cold storage ad coservato plat s dedcated to prolog te perod of food coservato, so te course of teco- ecoomc aalyss as bee sfted to take to accout oe to of food stuff stored cold storage ad coservato plat to be refrgerated ad coserved stead of cosderg te exteral walls area. I addto, ts paper provdes a more accurate formula to calculate te specfc cost of refrgerato equpmet bx order to skp te percetage of mstake used to occur calculatg te overall stadard eat trasfer coeffcet of exteral walls caused by applyg te wegted average value of te specfc cost of refrgerato equpmet bxa. Te obtaed results resultg from te use of a computer-programmed metod teco-ecoomc aalyss of te cost eaced te fact tat te mpact of cold storage plat capacty ad specfc cost of refrgerato equpmet o te ecoomcal tckess of te sulato layer s correct. Ts justfes te cocept proposed ts paper tat assocates te teco- ecoomc aalyss of costs to be te capacty of te cold storage plat stead of te exteror walls area ut, were obvous decease te values of te operatoal cost O c, O d ad te mmum cost ( P m wt te crease cold storage ad coservato plat capacty. Te results also sow tat ecoomcally optmal termal resstace ( Ro.ec of eat trasfer troug te exteror walls ad te ecoomc tckess of sulato layer ave bee effected by te specfc cost of refrgerato equpmet. It as bee otced tat bx decreases from wt crease of te cold storage plat capacty from 4 to 5 to. Ts leads to 6% decrease ecoomcally optmal termal resstace ad te ecoomcal tckess of te sulato layer. eywords: termal sulato, ecoomcal tckess, teco-ecoomc aalyss. Itroducto Te tesfcato of coolg of food stuff ad te ecoomcal tedecy of cosumg te eergy avalable, addto to te developmet of more effectve ew termal sulato materals requres te eed to revew te total eat trasfer coeffcet requred for te cold storage plat exteror walls o.req [4] based o tecoecoomc aalyss of cost related to termal sulato ad tat related to te producto of refrgerato to compesate for eat flow troug te cold storage plat exteror. Te goal of researcers te feld of food stuff coolg s to keep te utrtoal value of food stuff as log as possble wt mmum cost. Tckess of termal sulato of exteror walls ad te type of termal sulato tat sgfcatly effects te prmary captal ad operatoal cost of te cold storage plat sce te crease sulato layer tckess creases captal cost ad reduces te operatoal cost. Ts requres coductg a compreesve teco- ecoomc aalyss to calculate te ecoomc tckess of te sulato layer. I addto, te captal ad operatoal cost are flueced by te capactyof te cold ad coservato storage plat, wc tur affects te ecoomc tckess of te termal sulato layer. So, ts demads tat a study be carred out to determe ts tred ad value of ts effect. I researc [ ad 3 ] oe systematc metod was used to determe te exteror walls 7

2 ISSN -77 (Paper ISSN -87 (Ole Vol.4, No.5, 3 ecoomcal optmal termal resstace, wc s te verse value of k o.ec, wc represets moder metodologes used to determe te ecoomc effcecy of usg ew tecology te atoal ecoomy. Aalyss of te results of tese researc papers sows tat cost of te termal sulato spet o te refrgerator evelope ad o refrgerato producto to compesate for eat flowg from te outsde s assocated wt te surface area ut of te cold storage plat exteror walls, wc s cosdered as a arctectural dcato of te buldg. Ts ders te determato of te effect of rug cost,.e. operatoal cost tems, suc as ogog cost,cludg te cost of electrcal eergy requred for te operato of te refrgerato mace ad te cost of food stuff wegt loss due to dryg up, or food stuff ( trasprato ( M of te wall surface of te cold storage plat, ad tat ts does ot make sese. I cotrast, ts study stems from te dea tat te cold storage plat s dedcated to prologg food preservato ad t proposes wat agrees wt metodology umber [7], wc determes cost spet o te exteror walls termal sulato of cold storage plat ad o te producto of refrgerato to compesate for te eat flow from te outsde assocated wt te capacty of te cold storage plat. It s wort metog tat t sould be oted tat tere s a relatosp betwee te area of exteror surface of te cold storage plat ad ts capacty, as sow fgure. Ts ca be take to accout te value of te specfc area of te exteror walls ( Fsp Fo G, te value of wc s I te rage of (.55 M T to 4.. Fgure ( old storage plat of te capacty of 5-8 to are cosdered stadard projects. Oe of te cost tems s tat related to wegt loss of te stored food stuff wc occurs due to (trasprato caused by eat flow troug te exteror walls to cold storage plat. I fact, trasprato from food stuff appes ot oly because of eat flow troug te exteror walls, but also because of teral eat load, tat s te eat load of fas eges, lgtg, workers, ad so o, addto to te resprato process of stored food stuff assocated wt te release of eat. Ts study takes to accout compoets of food stuff weg loss caused by te trasprato due to eat flow effect troug te exteror walls oly. Accordg to te results reaced by researc [3], te percetage of ts wegt loss caused by te flow of eat troug te exteror walls does ot exceed 3% of te total wegt loss value caused by te trasprato te case of storg froze meat. Moreover, we calculatg te captal cost spet o refrgerato equpmet, te autors of researc tree suggest tat probable average value of te specfc cost bx of refrgerato equpmet wc equals bx.64 $/w be used despte te fact tat bx cages 4 tmes from. to.77. alculato by usg formula ( lsted researc [3] ad usg te data of froze-meat rooms at a teral temperature of - c º sow tat at te value of (bx. $ / w, te ecoomcally optmal termal resstace of eat trasfer troug te exteror walls of te coolg wareouse s R o.ec 4.4 M./W, wereas at te value of bx.77 $/w Te value of ( M W R o.ec 5. Ts s to say,.6 tmes. To preserve apple at ºc temperature ad bx. te value of R o.ec.7 M./W We bx s bx.77, te value of Ro.ec equals 3.8( M² /W Wc s 4 tmes te value we bx s.. It ca be cocluded tat usg wegted average value of te specfc cost of refrgerato equpmet were bx.64$/w, leads to a otable mstake percetage te calculato of te overall eat trasfer coeffcet of cold storage plat exteror walls w/(m.k. Ts requres tat a metod leadg to more accurate calculato of refrgerato equpmet specfc cost bx be reaced.. Teory We desgg cold storage plats, tckess of te termal sulato layer of te cold storage plat exteror walls s calculated, usg te formula ( below : I δ λi + λi ( Ro R ko. req aext λ at δ ( I equato ( certa eat trasfer coeffcet of te exteror walls s determed. Accordgly, tckess of te termal sulato tat meets te requred overall eat trasfer coeffcet s reaced k o.ec. Ts process s doe wtout coductg a teco- ecoomc study of te cost, wc meas tat te ecoomc aspect related to te desg of cold ad coservato storage plat s ot clear. To make te desg process le wt eergy ad cost -savg tred, equato ( s updated by replacg te total requred eat trasfer coeffcet o.req ad eat resstace of te exteror walls te equato by ecoomc total eat trasfer coeffcet k o.ec ad exteror walls eat resstace R o by ecoomc optmal termal resstace R o.ec, te formula sould rewrtte as 8

3 ISSN -77 (Paper ISSN -87 (Ole Vol.4, No.5, 3 δ λ R R ( I. ec. I ( o. ec Were δ.ec s te ecoomcal tckess of te exteror walls termal sulato. Te ecoomcally optmal termal resstace R o.ec lsted equato ( requres coductg a compreesve teco-ecoomc aalyss tat cludes te followg procedures : To determe more accurate specfcato of te specfc cost of refrgerato equpmet followg equato : b x all eq o eq all ( I + x bx wll be as te (3 Were, eq s te cost of coolg equpmet ad tools, $. all s te coeffcet of extra cost wc takes to accout coolg loss durg te passage of te refrgerat ppes ad applaces. Ts coeffcet equals.7 for drect coolg systems wtout secodary refrgerat. I coolg systems were salty solutos are used as secodary refrgerat te all s.. o s te coolg load o refrgerato system W. s te eat flow load troug te te cold storage plat exteror walls, W. x s te coolg load of food stuff, cotaers, fa eges, eat flow troug te floors, lgtg, workers te plats W. To calculate x, te metod preseted paper (8 s used. Te results from researc 8 coducted o oe-storey cold storage plat wt te capacty of 5-8 to sow tat s very less ta x, Were,. x Ts sows tat order to determe te value of bx wt a error rate acceptable egeerg calculatos, a equato tat does ot cota ca be used, so equato (3 ca be rewrtte te form: b x. eq (4 all x Fgure sows te relatosp betwee te cost of equpmet ad supples of a oe storey cold storage plat wt forced ar coolg uts or surface coolg uts of atural covecto (batteres, ad te cold storage plat capacty s bult based o te results of stadard projects by Gyprokoloda. It sould be oted tat formula ( ca be smulated by te followg lear equato: eq a + bg (5 Were, (a ad b are coeffcets derved from expermets (a 4, b5 for cold storage plats wt te capacty ragg from 5 to to, ad te values of (b68.6, a4. 4 are for cold storage plats wt capacty ragg from 8- to. Te above values are related to forced coolg system, ad te values (b9, a3. 4 are for storage capacty ragg from to 8 To equpped wt surface coolg equpmet -batteres- ( atural covecto. I te case of cold storage ad coservato plat equpped wt mxed equpmet (ar forced ad batteres wt storage capacty ragg from ( to 8 T, were te cost of equpmet ad devces of cold storage are wrtte as te followg equato : 4 G 4 ( G + ( 3 + G G eq 9 (6 G G Were, G,G are te cold storage cambers capacty of forced ar coolg system, ad battery system of 9

4 ISSN -77 (Paper ISSN -87 (Ole Vol.4, No.5, 3 atural covecto respectvely, to. Absolute losses food stuff wegt as a result of trasprato caused by eat flow troug exteror walls to ca be represeted te formula lsted researc (5 sow below: W 6 ( ε t. e ε cool (7 ε T.E s te tecologcal coeffcet of effcecy of te coolg system [6]. cool s te durato of storage of food stuff coolg mode, our. ε s te mosture termal property of te process, kj/kg, obtaed from formula (6 or (7 researc [5]. To reac a formula tat specfes ecoomc optmal termal resstace for eat trasfer troug exteror walls of te cold storage plat Ro.ec, ts study used te compoets of cost as suggested researc wt sgfcat modfcato order tat te cost ad expedture be based o te capacty of te cold storage ad coservato plat (G stead of te surface area ut of te exteror walls. Formulas (4 ad (7 gve te followg: Were P E ( (8 r c d Foλ ( R G o R + ( T + E. p r eqfo tmax +.allxgro F t O ref GR O ref ( T + E p. m a Fo t a GR o d 6 dfo tref ( t. e Gε R o ε P- Te cost of termal sulato of te exteror walls of te cold storage plat ad te cost of producg coolg to compesate for eat flow from outsde te plat, ad te cost resultg from food stuff wegt loss due to trasprato $/ ( to. year. E s te stadard effcecy coeffcet of captal vestmet, ad t s accepted at (.5. - captal cost o termal sulato $/(To. year r - captal cost o te coolg stato equpmet tat provde producto of coolg to compesate for te termal flow troug te exteror walls $/(To.year. c - Operatoal cost o year. te producto of coolg to compesate for termal flow troug exteror walls $/(To. - Operatoal cost o te producto of eatg for eatg refrgerato cambers te cold days of wter ref 3

5 ISSN -77 (Paper ISSN -87 (Ole Vol.4, No.5, 3 tme $/(To. year. d -Operatoal cost for loss resultg from wegt loss of food stuff as a result of eat flow troug te exteror walls of te cold storage store. - estmated cost of te termal sulato $ /m 3. E.p - coeffcet of dfferet tme cost, t s take as (.. T,T- tervals of cagg termal sulato ad te refrgeratg equpmet respectvely ( year. t max - dfferece betwee computatoal temperature of outsde ar t o max, obtaed by formula ( researc [], ad ar temperature te cold storage camber t c,. - te umber of replacemet of refrgerato equpmet,,3,. c, - te cost of te producto of refrgerato uder stadard codtos of compressors fucto ad cost of eatg for eatg te cambers te cold days of wter tme $/J. t ref, t -Te dfferece betwee te average temperature of te outsde ar, respectvely, te coolg perod t o.av.cool ad eatg perod t o.av. of te refrgerato camber, obtaed by formulas (8 ad (9 researc [3], ad ar temperature te refrgerato camber t c,. - durato of eatg of te refrgerator cambers, our. m,a,a - Refrgerato cost coeffcets stadard codtos for te compressors fucto, ad loss of coolg ad eatg ppes, respectvely wc ca be obtaed from researc [3]. d - Te cost of food stuff wegt loss caused by trasprato $/To. We te dervatve (dp/dr o s solved ad equated t to zero, after mapulato te followg equato s obtaed: R oec. E eq t max +. allx EλI + ( + E. p T ( + E [ + ]. p T + + c t cool cool E λ I m a + t eat T [ + ( + E ]. p eat a t d E λ I ( ε cool cool T. E T [ + ( + E ]. p ε (9 3. alculato procedures Te mecasm of coosg te ecoomc tckess of te termal sulato layer of te exteror walls (δ I.ec cludes te followg: Prelmary data for te calculato cludes te costructo locato of te plat, te plat capacty ad daly uploadg commodtes, te lay out ad dstrbuto ad coolg camber, clmate data for te costructo of cold storage ad coservato plat ad te temperature ad durato of coservato requred, clmate date of cold 3

6 ISSN -77 (Paper ISSN -87 (Ole Vol.4, No.5, 3 te locato of te cold storage plat, type of coolg system for eac of eac camber, compoets of exteror walls ad celg structure, caracterstcs termal propertes of wall ad celg materals, cost dcators of termal sulato materals ad electrcal eergy requred for te producto of coolg ad wegt loss of food stuff due to te trasprato. alculatos are carred out for eac exteror wall of refrgerato cambers depedg o te locato of te wall, as well as te celg accordg to te followg formulas: Out of formula (9 we fd te value (R o. ec, ad te two values (δ I. ec ad Pm wc are obtaed by usg te formulas below: I. ec λi o. ec ( R R δ ( Were P E F λ ( R R oj I m + T o. ec Gj ( + E. p ( R δ + + aext λ a t F oj - te surface area of te exteror walls of te coolg camber (m. G j - s te camber coolg capacty (To. Smlar calculatos ca be made for oter sulato materal tat ca be possbly used. Te results of tese calculatos are used to select materals for termal sulato, were te sum of te values (P m s te least for all coolg rooms te cold storage ad coservato plat. 4. Results ad Dscusso A computer program as bee used ad t was specfcally bult to calculate ecoomcal optmal termal resstace of te exteror walls of te cold storage ad coservato plat (R o.ec, relatve wegt loss of te stored food stuff due to trasprato because of eat flow troug te exteror walls (ΔG W /G ad te mmum cost (P m as follows: alculatos ave bee doe for meat stores wt te capacty of 5 to 5 tos, ad te teccal effcecy coeffcet (ε T.E wc s varable. Tese calculato ave bee made by cosderg te te followg facts: 4.8 $/m 3 ; T 5 years; T.5 years; t c - ; ; t max 67.9 ; t cool 8 ; c $/J; z eat ; m.4; a.7; d.78 $/kg; cool s; PSP-S (λ I.47 W/(M.. Te aalyss of results lsted Table ( sows te followg: - we te G s a fxed value, ad ε T.E s varable ( -, te values R o.ec ad P m are decrease by ( tmes. Rato relatve loss te wegt of food stuff resultg from trasprato falls from te maxmum value of.44% to % (% we ε T.E. - we ε T.E s fxed ad te capacty of te cold storage plat s varable, from 5 to 5 tos, te value ΔG goes dow by 3. tmes, wle P m wll be reduced by 3 tmes. Ts s explaed by te bg effect of te specfc area of te exteror walls surface o tese dcators. 3- Te relatosp betwee R o.ec ad te capacty of cold storage plat ad coservato plat s determed accordg to te metod or beavor cage of value b x. So, we G4-5 to, te value R o.ec decreases we capacty creases. Ts s explaed by te avalablty of freezg rooms tese cold storage plats, ad by te value (b x I 5- to capacty coolg camber R o.ec s lower ta tat 4-5t o-capacty plat due to te lack of fast coolg rooms were (b x te larger te cold storage plat capacty, te lower te ecoomc tckess of te sulato layer δ I. ec, ad te operatoal cost O c, O d as well as te mmum cost P m wll be lower. 3

7 ISSN -77 (Paper ISSN -87 (Ole Vol.4, No.5, Ecoomc tckess of te sulato layer δ I. ec s assocated wt a drect correlato wt te value (λ I / /, wle te operatoal cost O c, O d ad te mmum cost P m wll be assocated wt drect correlato wt te same values but dfferet form (λ I / te same codtos. 6- So, It s clear tat te selecto of effectve termal ecoomc approprate sulato materal sould be reaced accordace wt te dverget (λ I / λ I /, were te umbers ad are assocated wt te frst, ad tat te secod termal sulato materals compared te dverget are dfferet pyscal ad termal propertes, as well as cost dcators. We te symbol ( s aceved, ts meas tat tere are two beefts, te frst of wc s tat te cost goes dow ad te secod beeft s tat te tckess of te sulato layer s also reduced. O te oter ad, tere wll be oe beeft we ( s aceved, tat s te tckess of te termal sulato layer wll be reduced at te same quatty of cost. 5. ocluso: We desgg cold storage plat, t s ecessary to calculate te ecoomcal tckess of te termal sulato layer, takg to accout ot oly te locato of te plat ad te temperature sde te plat, but also te teccal effcecy of te refrgerato system tat wll be used as well as te capacty of te cold storage plat. Refereces Gedoya, A. G.,lefaov, B. V.,odereova, V.T. (98, About optmzato Tckess of te termal sulato of te exteral walls of te coolg wareouses ad coservato, Refrgerato Tecology (, 9-3. Gedoya, A. G.,faste B. A. (98, Determe te outsde temperature te summer for te purpose of calculatg te greatest eat flow to te coolg wareouse ad coservato, Refrgerato Tecology ( 9, 9-3. Gedoya, A. G.,faste B. A., odereova, V.T. (98, Resstat exteror walls of a refrgerated wareouse for termal trasfer, Refrgerato Tecology (, Dyraof, E. F.,Lefaof, B. V.,ojevekov, E. G. (98, Improve te propertes of termal sulato materal for walls of cold storage ad coservato, Refrgerato Tecology (4, 4-9. Jada, V.. (979, Termodyamc teory of termal-umdty processes cold storage plat. Refrgerato Tecology, (6, Jada, V.. (975, omparso of oolg Systems, Refrgerato Tecology (, MENMYOMOLPROM. (978, Metod of determato of te ecoomc effectveess of usg ew created tecology dustry of meat ad mlk: SSR, GOSTORGEDAT..(96, Glossary of Refrgerato tecology, Fsp, M/T G, T Refrgerators dstrbuto old storage of fruts ad vegetables Fgure. te effect of te cold storage plat capacty o te specfc area of te plat exteror walls. 33

8 ISSN -77 (Paper ISSN -87 (Ole Vol.4, No.5, 3 eq, tousad dollars Refrgerators dstrbuto old storage of fruts ad vegetables G,T Fgure : te effect of te cold storage plat capacty o te cost of equpmet ad supples of te cold storage plat. Table. Result Seet of alculato ε R o.ec, m.k/w ΔG W /G, P m, $/ (T. Year at G, T at G, T at G, T

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