Kombinovani kompresiono-apsorpcioni ciklus - uticaj nekih važnih parametara na koeficijent grejanja i poređenje sa kompresionim ciklusom
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Apstrakt
Ovaj rad opisuje dve glavne analize: parametarsku i uporednu analizu. U parametarskoj analizi posmatra se kompresiono-apsorpciona toplotna pumpa (engleska skraćenica CAHP). Proučava se osetljivost njenog koeficijenta grejanja (engl. skraćenica COP) na promenu dužine cevi duž kojih se sliva film tečnosti u apsorberu i desorberu, raspodelu površine razmenjivača toplote i promenu koncentracije rastvora u apsorberu. Utvrđeno je da relativna raspodela između desorbera i apsorebra ima mali uticaj na koeficijent grejanja. Površina razmenjivača toplote za rastvor i promena koncentracije u apsorberu imaju veliki uticaj na koeficijent grešaka kada se posmatraju odvojeno, međutim kada se posmatraju zajedno i uz optimiziranu promenu koncentracije za svaku raspodelu površina, ukupan uticaj je mali. Prikazano je da ceviniz koje se sliva rastvor treba projektovati tako da budu što duže kako bi se povećao koeficijent grejanja. Uporedna analiza obuhvata novi postupak za poređenje performansi (COP) kompresiono-apsorpcione pumpe (CAHP) sa kompresionom toplotnom pumpom (engleska skraćenica CHP). U ovom postupku uzeti su u obzir lokalni koeficijenti prelaza toplote i pada pritiska. Dalje, poređenje se vrši za različite primene u oblasti grejanja i za određeni nivo ulaganja. Primene u oblasti grejanja i izabrane su za proučavanje tri različite vrste uticaja i to: veličine promene temperature (temperaturskog klizanja) ponora i izvora toplote, porasta temperature za dato temperatursko klizanje ponora i izvora toplote i temperaturski nivo "klizajućih" ponora i izvora toplote. Smeša amonijka i vode se koristi kao radni fluid kod CAHP, a izobutan kodn CHP. Pretpostavlja se relevantno industrijsko rešenje za CHP (uključujući indirektnu spregu sa ekonomajzerom, razmenjivač toplote usisne pare, pothlađivač i povećanje površine kod isparivača i kondenzatora), što nije slučaj u prethopdnim poređenjima ovog tipa. Apsorber i desorber u CAHP su modelirani kao vertikalni dobošasti razmenjivači toplote. Glavni rezultati ove uporedne analize su sledeći: (1) koeficijent grejanja CAHP je dobar kao i kod CHP kada su klizanje temperatura ponora i izvora toplote 10K; (2) kada se klizanje temperature ponora i izvora toplote povećava na 20K, CAHP ima bolje performanse za 12%; i (3) veći porst temperature i veći temperaturski nivo daju relativno loš koeficijent grejanja kao CAHP. Za CAHP su predloženi neki projektni parametri za povećanje koeficijenata grejanja koje treba još proučavati.
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