NGHIEN cufu - TRAO D6| THU H I NHIET THAI lir MAY OI^U HOA KHONG KHi N N G DE TIET KIEM NANG LU'ONG TRUNG TAM DUN NU'QC HEAT RECOVERY FROM CENTRAL AIR CONDITIONING FOR IVIANUFACTURING HOT WATER TO SAVE ENERGY GVC,TS Bui Ngoc Hung Trudng Dai hpc Bach Khoa, Dai hpc Qudc gia TP Hd Chi Minh TOM T A T Hien nay, hdu het cdc nguon nhiet thdi tie thiet bi ngung tu cda cdc mdy lanh cong nghiep diu thdi mdi truong cdc nhd mdy co nhu cdu nu&c nong dephiic vu cho cdc qud trinh sdn xudt phdi sif dung cdc nguon nang lugng khdc nhu dien hodc hai nu&c, de tgo nu&c ndng Nhdm muc dich tiet kiim ndng lugng, bdi bdo ndy dua mpt phucmg dn thu hoi nhiet thdi tic cdc he thong mdy Ignh trung tdm cong sudt lan de dun nu&c nong phuc vu cho cdc nhd mdy nhu thuy sdn, che bien thuc phdm .Mpt mo hinh thuc nghiem dd dugc hodn thdnh sic dung ddn ngung cua mdy dieu hoa khong trung tdm kit hgp v&i bp trao doi nhiet doi lieu cu&ng bice dgng tdm Bdng viec so sdnh cdc thong so tinh todn v&i cdc thong so hogt dpng cda mo hinh dd chimg minh mo hinh su dung ddn trao doi nhiet doi lieu cudng bice dgng tdm co nhiet dp nu&c ndng thu hoi dat din 75''C hodn todn ddp ung dugc cho cdc nhu cdu ve nu&c nong cong nghiep che bien ciing nhu vi$c thu hoi nhiet thdi khong dnh hu&ng den hogt dpng binh thucmg cita mdy dieu hoa khong trung tdm Tu khda: Nhiet thdi; Nu&c nong; Diiu hoa; Tiet kiem ndng lugng ABSTRACT Currently, most of the waste heat from the condensers of the industrial air conditioning are discharged into the environment, while plants that need water for the manufacturing processes using energy sources such as electricity or steam to create hot water For the purposes of saving energy, this paper studies a method for recovery of waste heat from the central air conditioning systems to heat waterfor using in plants such as fisheries, food processing An empirical model was completed using condenser of the central air conditioner and forced convection plate heat exchanger By comparing the calculated parameters with the operating parameters of the model has proven that model used forced convection plate heat exchanger has hot water temperature reached to 75°C that fully meet for the needs of hot water in industrial processing as well as the recovery of waste heat does not affect the normal operation of the central air conditioning Keywords: Waste Heat; Hot Water; Air Conditioning; Save Energy ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, So 1+2 nam 2015 www.cokhivietnam.vn NGHIEN cufu-TRAOD6| DAT VAN DE Nhiet thai tii thilt bi ngung tu cua he thdng lanh dugc xem la ngudn nhiet thai cd nhiet dp thip Co nhilu phuong an dl thu hdi nhiet thai cua he thdng lanh, nhien phd biln thudng la sii dung ngudn nhiet de dun ndng nudc phuc vu smh boat hoac gia nhiet sa bd cho cac qua trinh cdng nghiep [1] Ddi vdi viec su dung may dilu hda khdng hien nay, chua cd mdt nghien ciiu cu the ve lupng dien nang tieu thu hang thang cac hd gia dmh cd su dung may dilu hda Tuy nhien, neu dua vao cac sd lieu thdng ke, cong suat dien tieu thu cho be thdng dilu hda frong cac cdng trinh nhu cao dc, van phdng, khach san chiem td 45% den 55% tdng lugng dipn tieu tbii [2] Ngoai ra, may nudc ndng cung duoc xem la mgt nhiing thilt bi tieu thu dien Idn so vdi cac thiet bi dien gia dung khac [3] Den da cd nhieu nghien cuu de giam lupng dien nang tieu thu cua may dieu hda khdng va may nudc ndng Ddi vdi may dieu hda la thay ddi nhiet dp cai dat ban ngay, ban dem, thay ddi luu lugng khdng theo phu tai thuc te [4] hoac su dung bom nhiet de tiet kiem nang lugng [5] Viec sir dung dng nhiet dao dpng dl thu hoi nhiet thai tir thiet bi ngung tu dang dng-vd da dugc thyc hien bdi Ngoc Hung Bui va cac cpng sy [6] Vdi h^ thdng dieu hda khdng khi, P Sathiamurthi va PSS Srinivasan [7] da ket luan tinh kha thi va hi?u qua kinh te cua he thdng thu bdi nhiet thai tu may dieu hda khdng trung tam cdng suit 16 tons lanh de cung cap nudc ndng cho sinh boat cua 600 sinh vien mdt ky tiic xa Trong ITnh vyc dan dung, M M Rahman, Chin Wai Meng va Adrian Ng [8] da nghien cuu he thdng thu hdi nhiet thai dun nudc ndng tir may dieu hda khdng dan dung vdi thilt bi trao ddi nhiet bang dng dong quan ben ngoai vd cua binh nudc ndng va da ket luan ring cd the gia nhiet nudc binh tu SO^C din 75°C vdng gid may dieu hda hoat dgng Trong nudc, Nguyen Dinh Vinh, Ha Dang Trung da nghien ciiu thilt ke, che tao va thii nghiem thiet hi bom nhiet dun nudc ndng sii dung tac nhan lanh R22 va dan lanh khdng dieu kien hau Viet Nam [9] Cac tac gia da ket luan thiet hi bom nhiet dun nude ndng cd COP dat 3,3 din 3,8 dilu kien mdi trudng nha 22 "C va am 60%, tiet kiem dugc 65% den 70% nang lupng tieu thu so vdi binh dun nudc ndng bang dien Bui Ngpc Hiing da nghien ciiu va che tao md hinh thu hdi nhiet thai hi dan ngung cua may dieu hoa khdng cdng suat nhd dun nudc ndng de tiet kiem nang lugng [10] va da ket luan viec thu hdi nhiet thai ngoai viec tiet kiem nang lupng thi cung khdng anh hudng den hoat dpng binh thudng cua cac may dieu hda khdng cdng suat nhd De tiet kiem nang lupng viee dieu hda khdng va dun nudc ndng, bai bao trinh bay viec nghien cuu thiet ke che tao md binh thu hdi nhiet thai tii dan nong cua cac may dilu hda khdng trung tam de dun nudc ndng d qui md cong nghiep phuc vu cho cac nhu cau vl nudc ndng vdi sd lugng Idn nhu cac khach san hoac cac nha may che bien thuy san, Mo hinh su dung dan trao doi nhiet dang tam dd nudc ndng binh dugc bom tuan hoan qua dan trao ddi nhiet tam de thu hdi nhiet thai '"^ ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, S6 1+2 nam 2015 wHTv.cokhivietnam.vn NGHIEN cufu-TRAO D6| Bdng Thong sd cua cdc diem trgng thdi tren thi T- S su dung tdc nhdn Ignh R22 PHirONG PHAP NGHIEN CUtJ 2.1 Cac y§u t6 anh hu-dug den viec thu hhi nhiet thai t u may dieu hoa Ididng R22 ironethdi tra PlbfeT] 4.ằU tUUAti L tWJ^ ã lkVlô.lQ 1./4/S 10 4.H3 7' -1 ei.H 5C in 19.3)S 1».39S 7il,U HT.taa 1.7M3 c J.SS3 1,77*3 7lfi.7a 5S2.75 1.2291 Vdi may dieu hda khdng su dung tac nhan lanh R22, gia tri COP ly thuylt d cac nhiet ngung tu khac dupe tinh theo cdng thiic (1) va dupfc trinh bay bang Qua bang nhan thay gia tri COP cang cao nhiet ngung tu cang thap Hinh 1: Sa nguyen ly cda mdy dieu hda khdng Dd thi T - S cua so nguyen ly may dieu hda (hinh I) dupe thi hien tren hinh Quan sat tren thi T - S nhan thiy cd thi thu hdi toan bp lugng nhiet ngung tu qN neu nhiet nude ndng sii dung cd gia tri nhiet thap hon nhiet dp ngung tu cua he thdng lanh giai nhiet bang nudc Neu toan bd lugng nhiet thai d thilt hi ngung tu dupe thu hdi, ta cd he sd thu hdi nhiet thai ly thuyet dugc dnh nhu sau: (1) Bang 2: Nhiet sau mdy nen, dp sudt ngimg tu vd he sd COP nhiet thdi cda R22 tgi cdc gid tn nhiet dp ngung tu khdc nWtAdwniila I'd n to ctr B1.H 7AR2 6:.» U.19S 17JK li.iiS &JKH] Bdng 3: Nhiet dp sau mdy nen ciia mpt sd tdc nhdn lanh thdng dung a nhiet dp ngung tu 50'C T»-,i.,^ NhUaittuH >n*v n*> /fnhlft iff i V f i i 'v SO^ Hit •1-M MOK nuo* 79 n 2.2 Tac nhan lanh va cac thdng s6 ho^t d6ng Hien nay, cac may dilu hda khdng dang dugc su dung vdi nhieu loai tac nhan lanh khac nhu dugc trinh bay cac bang 1,2 va Dya vao cac thdng sd trang thai cua nhiing diem dac biet tren chu trinh vdi cac loai tac nhan lanh nhuR22, R4I0A, R407C, RI34a nhan thay nhiet dp sau may nen phd biln khoang 78°C d i n 82''C, d nhiet dp ngung ty ISSN 0866 - 7056 TAP CHi C O KHi VIET NAM, Sd 1+2 nam 2015 www.cokhivietnam.vn NGHIEN cufu-TRAO D O I 50°C Vdi tac nhan lanh R22 nhiet ngung tu thay ddi khoang 40°C den SO^C thi nhiet dp sau may nen thay ddi khoang 68''C den 82''C Tuy nhien, nhiet dp ciia tac nhan lanh sau may nen (dilm tren thi T-S) cd the cao hon [11], may lanh boat dpng vdi chu trinh thyc te cd cac tdn that ap suat cua thiet bi ngung tu, bay hoi cdng nhu qua trinh nen khdng doan nhiet va khdng thuan nghich may nen nhu dupe the hien hinh ndng thu hdi, md hinh su dung thiet bj trao ddi nhiet dang tam ddi luu cudng buc He sd truyen nhiet tu hoi tac nhan lanh qua nhiet d diem den trang thai hoi bao boa d diem 2' dugc tinh theo qua trinh truyen nhiet pha giiia dong hai d phia cua cac tam truyen nhiet va nudc ddi luu cudng biic d phia cdn lai cua tam nhu sau: NuPi (3) (4) Va d|j la dudng kinh tuong duong cua Idp nudc chuyen ddng giua tam Hinh 3: Do thi T-S cua chu trinh Ignh thuc Theo [12] he sd tda nhiet ngung tu cua hoi tac nhan lanh tren be mat tam phang dat diing va nudc ddi luu cudng buc d mat lai cua tim duge tinh theo cdng thiic nhu sau: ReXi (5) Nhu vay, he sd thu hdi nhiet thai thyc 8750 + 58Pr-''-MRe"''-253 u; te cd the dugc tinh tren co sd lugng nhiet nudc ndng binh nhan dugc va dien nang tieu Cdng suat truyen nhiet cua thiet bj trao thu cua may dieu hda cu the theo cdng thiic nhu ddi nhiet dang tam dugc chpn tren co sd dam sau: bao ca qua trinh trao doi nhiet noi tren COP, = (2) 2.4 Md hinh thuc nghiem sir dung thiet hi thu hdi nhiet thai d^ng tam 2.3 Tinh chon cong suit thilt hi trao ddi nhi^t dfing dl thu hdi nhiet thai '[IDL- Cd nhieu loai thiet hi trao ddi nhiet cd thi sii dyng, theo kieu truyen nhiet co the phan logi ddi luu ty nhien va ddi luu cuong biic Vdi viec thu hdi nhiet thai tir may dieu hda cdng suit Idn, de tang tdi da nhiet cua nudc R Hinh 4: So nguyen ly ciia mo hinh thuc nghiem ^ ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, Sd l+2nam20I5 www.cokhivietnam.vn NGHIEN cufu-TRAO D I Md hinh dugc thiet ke de thu hdi nhiet thai tu I may dilu hda cdng suit 24000 BTU/h sir dung tac nhan lanh R22 May dieu hda dang dugc sir dung de dieu hda nhiet cho I phdng lam viec c6 dien tich 70m^ vdi 10 nhan vien lam viec va cae thiet bi van phdng De thu hoi nhiet thai, dan ndng dugc trang bi them thiing nudc ndng dung tich 300 Hinh 6: Hinh dnh thuc ti cua md hinh lit, I thiet bi trao ddi nhiet dang tim, I bom man hoan cdng suat SOW, he thdng dng din va Cac thdng so nhiet mdi trudng, nhi^t cac thiet bi Mdt van by-pass dugc trang bi dp tac nhan lanh vao va bp trao ddi nhiet, ap de cd the boat ddng md hinh d chi dp cd thu suat ngung tu va ap suat bay hoi cung dugc hdi nhiet thai va khdng cd thu bdi nhiet thai ddng thdi De nudc ndng binh cd nhiet Cac thdng sd ve cudng ddng dien va cao nhat, viec trao ddi nhiet giiia nudc va tac dien ap duge ghi nhan suit quaft-lnhthi nhan lanh thiet hifraoddi nhiet dang tim nghiem dugc bd tri chuyen dpng song song ngugc chilu giiia nudc ndng va tac nhan lanh nhu hinh ve KET QUA VA THAO LUAN Ngoai ra, thiing nude ndng dugc bgc each nhiet bang vat lieu thermaflex cd bl day 20 mm de giam tdn that nhiet cua nudc ndng mdi trudng ^^^^^±yy Hinh 7: Si^ thay ddi nhiet dp trung binh cua nu& ndng binh lich trie theo th&i gian Hinh 5: Sa nguyen ly ciia thiet bi trao ddi nhiet dgng tdm Cae sd lieu thuc nghiem dugc ghi nhan ddng thdi theo thdi gian tai nhilu thdi diera Vdi may dilu hda khdng cd cdng khac de the hien cho boat dpng suat 24000 Btu/h, thay cac gia tri sd cua tac cua may dieu hda thyc tl va dugc the nhan lanh R22 bp trao ddi nhiet ddi luu hien bang cac dd thi nhu sau: cudng biic dang tam truyen nhiet vdi nude ndng CO nhiet dp trung binh 40''C vao cac cdng Su thay doi nhiet cua nudc ndng thiic (3), (4) va (5) ta co dupe tdng dien tich binh theo thdi gian duoc the hien tren truyin nhiet cua thilt bi la 0,6 m^ hinh Nhiet nude thay ddi tu 31°C din 68*'C ISSN 0866 - 7056 TAP CHi CO KHI VIET NAM, Sd 1+2 nam 2015 www.cokhivietnam.vn NGHIEN cufu TRAO D I hong thdi gian gid 30 phut Liic diu nhiet dg cua nudc tang nhanh nudc binh co nhipt thap nen phan Idn lupng nhiet thai ciia may dieu hda dugc nudc hip thu va he thdng cd the xem nhu dugc giai nhiet bing nudc Khi nhiet dp nudc tang, nhiet dp ngung tu va ap suSt ngung tu se tang theo Khi ap suat ngung tu tang den gia tri bang gia tri cua he thdng giai nhiet bang khdng thi lupng nhiet ma nudc binh nhan dugc bat dau giam Iam cho nhiet dp cua nudc binh tang cham lai va nhiet dp nudc cao hon nhiet dp ngung tu thi nudc chi cdn nhan dugc phan nhiet lugng qua nhi?t eua tac nhan lanh (tii diem den diem 2' tren dd thi T - S) va cudi cung se dat gia tri Idn nhit phu thugc vao nhiet dp cua tac nhan lanh sau may nen (diem tr6n thi T - S) va chenh l^ch nhiet dp eua nudc va tac nhan lanh thiet bi trao ddi nhiet dang tam Do loai thiet bi trao ddi nhiet dang tam co chenh lech nhiet dp rit nhd (khoang I^C) nen nhiet dp nudc ndng binh cd thi dat gia tri nhiet gan bang nhiet dp ciia tac nhan lanh sau may nen Hinh trinh bay su thay ddi cua ap suat ngung tu theo nhiet dp nudc ndng binh tich trii Theo hinh nhan thiy rang nhiet dp nudc binh tich tru cang tang thi ap suat ngung tu cang tang Tuy nhien, nhiet dp nude Idn hon 50°C thi ap suit khdng tang va giu dn dinh d gia tri gan bing vdi gia tri ap suit ciia he thdng khdng thu hdi nhiet thai Dilu la bg trao ddi nhiet thu hdi nhiet thai hong md hinh thyc nghiem dugc lip ndi tilp vdi dan ngung giai nhiet bang khdng khi, dd nhiet nudc ndng binh tang cao hon nhi?t ngung tu tuong iing vdi ap suit ngung tu cua may dilu hda giai nhiet bang khdng thi tac nhan lanh bat dau ngung tu dan ndng cua may dieu hoa va he thdng boat dpng d ap suit ngung tu dn dinh tuong iing vdi gia tri ciia may dilu hda giai nhiet bing khdng Hinh 8: Su thay doi dp sudt ngimg tu theo nhiet cda nu&c nong binh tich trie Do ap suat ngung tu cua thiet bi ngung tu giai nhiet bang khdng phu thupc nhiet dp mdi trudng va phu tai phdng, nen cac thong so thay ddi lam cho ap suat ngung tu dao ddng the hien bang cac gia h-i ap suat giam va tang lai dugc the hien tren hinh Hinh trinh bay sy thay ddi cudng ddng dien cua md hinh theo thdi gian trudng hgp he thdng cd thu hdi nhiet thai va khdng cd thu hdi nhiet thai (sii dung van bypass md hinh thyc nghiem) Ddi vdi trudng hgp khdng cd thu hdi nhiet thai thi cudng dp dong dien tuong ddi dn dinh sudt thdi gian he thdng boat dpng (dupe thi hien bing dudng net diit tren hinh 9) Ddi vdi trudng hop cd thu hdi nhiet thai, he thdng mdi bat dau boat dpng, cudng dp ddng dien co gia tri nhd hon gia tri dinh miic nhiet nudc ndng binh thu hdi cdn thip Khi nhiet dp nudc tang dan thi cudng ddng dien tang, nhung vin khdng vupt qua gia tri boat dpng cua he thdng trudng hgp khdng thu hdi nhiet thai Dilu cd nghia vdi he thdng cd thu hdi nhiet thai, cd the tiet kiem mdt phin dien nang nhiet nudc binh tich trii ed gia tri nhd hon 40''C ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, Sd 1+2 nam 2015 wwTv.cokhivietnam.vn NGHIEN cufu-TRAO Ddi ^,^^/iv, ^ - " / ^ ^ / / ,»^^™ ,„, ' - ' • • - • < - * " > • / — ••" N M t l d4 mriJc ndng Dong Unli I * q Hinh 9: Sif thay doi cu&ng dp ddng dien ciia mo hinh theo th&i gian Tuy nhien, quan sat tren hinh nhan thay rang trudng hop cd thu hdi nhiet thai thi cudng ddng dien khdng dn dinh so vdi hogt ddng d che dp binh thudng Dieu dugc giai thich la trudng hgp ed thu hdi nhipt thai thi trd lue ciia ddng tac nhan lanh qua thiet bi ngung tu cua he thdng tang eao hon so vdi trudng hpp khdng ed thu hdi ddng tae nhan lanh phai di qua bg trao doi nhiet thu hdi va sau tiep tue di qua thiet bi ngung tu cua he thdng Dieu lam cho nhiet cua tac nhan lanh sau may nen tang cao hon so vdi trudng hgp khdng cd thu hdi Tuy nhien, ddng tac nhan lanh sau khdi may nen thai nhiet cho nudc bd trao ddi nhiet thu hdi nen nhiet dp cua may nen van khdng vupt qua gia tri eho phep cua nha san xuat va he thdng van boat ddng dn dinh Hinh 10 trinh bay sy thay ddi cua he so COP thu hdi nhiet thai thuc te theo nhiet dp cua nudc ndng binh tich trii Qua hinh 10 nhan thay he sd COP thuc tl bit diu giam nhipt dp nudc cao ban 40''C Khi nhiet dp nudc ndng cang cao thi gia tri COP thyc tl cang giam Hinh 10: Su thay ddi ciia h4 so COP thu hoi nhiet thdi theo nhiet dp nu&c ndng binh tich trie So sanh gia tri ciia he sd COP thyc te vdi gia tri cua he sd COP ly thuyet bang nhan thay nhiet dp nudc ndng binh cd gia tri nhd ban 40°C thi lupfng nhiet thai thuc te thu hdi dugc khoang 50% den 60% so vdi ly thuyet Khi nhiet dp nudc ndng binh tang den 45''C thi chi cdn thu hdi dupe khoang 25% va lupng nhiet thu hdi se giam din nhiet nudc binh cang tang Dieu cd nghia la he thdng chi hoat ddng hieu qua nhiet dp nudc ndng can su dung cd gia tri nhd ban 40°C Hinh 10 cdn thi hien nhiet nudc ndng tang thi lugng nhiet thai thu hoi giam, hoat ddng cua he thdng lanh van khdng anh hudng dang ke md hinh thyc nghiem da dugc thiet ke cd bd trao ddi nhiet thu hdi va thiet bi ngung tu ndi tiep nhau, cd nghTa la trudng hop nhiet nudc ndng tang qua cao den gan gia trj cua nhiet dp tac nhan lanh sau may nen thi toan bp tac nhan lanh van cd the ngung tu thiet bi ngung tu ciia may dieu hda Ngoai ra, md hinh da duge thu nghiem hoat ddng lien tuc de kiem tra dp ben tir nam 2012 din va hien van dang boat dpng dn dinh ISSN 0866 - 7056 TAP CHi C O KHi V I £ T NAM, Sd 1+2 nam 2015 www.coldiivietnam.vn NGHIEN cufu-TRAO D | Ngay nhan bai: 05/02/2015 Ngay phan bien: 09/02/2015 Tai lieu tham khao: Hinh 11 He thdng thu hdi nhiet thdi tic mdy diiu hda trung tdm dugc img dung tgi nhd mdy sdn xudt dugc phdm &Khu Cong nghiep VSIP (Binh Duang) KET LUAN Lupng nhiet thai cd thi thu hdi hi may dieu hda khdng phu thudc rit nhilu ylu td ve dieu kien boat dpng nhu: nhiet dp ngung tu, nhiet tac nhan lanh sau may nen, nhiet dp va lugng nude ndng su dung Ngoai ra, edn CO nhung yeu td lien quan den thilt hi nhu tac nhan Ignh, loai thilt bi trao ddi nhiet He sd COP thu hdi nhiet thai thyc tl phu thupc vao nhiet dp nude ndng binh thu hdi, nhiet dp nudc nong sir dung cang cao thi gia tri COP cang giam va he thdng chi boat dgng hieu qua nhiet nudc ndng can su dung CO gia tri nhd bon 40'*C So su dung thiet hi trao dang tam cd nhiet dp nudc ndng dat 75''C nhung he so thu hdi nhiet thai ban tdn nang lugng cho bom tuan ddi nhiet dupe den COP nhd hoan Viec tan dung nhiet thai khdng anh hudng den boat dpng binh thudng eua may dilu boa khdng Khi he thdng cd thu hdi se det kiem mdt phan dien nang tieu thu nhiet dd nudc binh tich tru thip ban 40''C.*> [I] Robert Goldstick, Albert Thumann, CEM, PE - The Waste Heat Recovery Handbook - The Fairmont press, INC [2] TS Le Chi Hiep (1998), Ky thugt diiu hoa khdng khi, NXB Khoa hpc va Ky thuat [3] So tay hu&ng ddn thdng tin sdn phdm mdy nuac nong ndng lugng mat tr&i (2009), Tmng tam Tilt kiem Nang luong TP H6 Chi Minh [4] Nguyen The Bao va Lam Thanh Hung, Sa dd md phdng he thdng lam Ignh bay hai co su dung chdt hdt dm lithium chloride dieu hda khdng nhdm tiet kiem ndng lugng Tap chi Khoa hpc va Cong nghe Nhiet, s6 92, thang 3/2010 [5] Nguyen Manh Hung, Bam Nhiet v&i chuang trinh tiet kiem ndng luang vd hu&ng nghien cicu m&i Tap chi Khoa hoc va Cong nghe Nhiet, s6 86, thang 3/2009 [6] Ngoc - Hung Bm, Ju - Won Kim, In - Seung Jang, Jeung - Kil Kang, And Jong - Soo Kim ^'Study On Performance Evaluation Of Oscillating Heat Pipe Heat Exchanger for Low Temperature Waste Heat Recovery''' Intemational Jouraa! Of Air - Condidoning And Refrigeration [7] P Sathiamurthi va PSS Srinivasan - Design and Development of Waste Heat Recovery System for air conditioning Unit - European Journal of Scientific Research ISSN 1450-216X Vol.54 No.l (2011),pp.l02-110 [8] M M Rahman, Chin Wai Meng vaAdrian Ng -Air Conditioning and Water Heating-An Envuonmental Friendly and Cost Effective Way of Waste Heat Recovery-AEESEAP Journal of Engineering Education 2007, Vol 31, No [9] Nguyen Dinh Vinh, Ha Dang Trung, Thiet ke che tao va thu nghiem bcrm nhiet dun nudc n6ng sir dung dan lanh khong - Tap chi Khoa hpc va Cong nghe Nhiet, s6 68 thang 3/2006 [10] Bui Ngoc Himg, Tan dung nhiet thdi tir ddn ngimg mdy dieu hda khong cong sudt nhd dun nu&c nong de tiet kiem ndng lugng Tap chi Khoa hpc va Cong nghe Nhiet, s6 108, thang 11/2012 [11] Roy J.Dossat - Principles of Refrigeration Prentice Hall, INC [12] Yunus A Cengel (1998) - Heat Transfer: A Practical Approach - McGraw Hill ISSN 0866 - 7056 TAP CHi CO KHi VIETNAM, Sd 1+2 nam 2015 www.cokhivietnam.vn ... thi lupfng nhiet thai thuc te thu hdi dugc khoang 50% den 60% so vdi ly thuyet Khi nhiet dp nudc ndng binh tang den 45''''C thi chi cdn thu hdi dupe khoang 25% va lupng nhiet thu hdi se giam din... nhiet noi tren COP, = (2) 2.4 Md hinh thuc nghiem sir dung thiet hi thu hdi nhiet thai d^ng tam 2.3 Tinh chon cong suit thilt hi trao ddi nhi^t dfing dl thu hdi nhiet thai ''[IDL- Cd nhieu loai... theo thdi gian trudng hgp he thdng cd thu hdi nhiet thai va khdng cd thu hdi nhiet thai (sii dung van bypass md hinh thyc nghiem) Ddi vdi trudng hgp khdng cd thu hdi nhiet thai thi cudng dp dong