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Unformatted text preview: Refrigeration Cycles Page 1 I deal Cycle I sentropic compression, P = constant q rejection, I senthalpic expansion, P = constant q addit ion COP R = q NETL /w I N = (h 1 – h 4 )/(h 2 – h 1 ); COP H P = q NETH /w I N = (h 2 – h 3 )/(h 2 – h 1 ) 1 2 3 4 State 1 = sat. vapor, State 3 = sat. liquid, s 2 = s 1 , P 3 = P 2 , h 4 = h 3 , P 4 = P 1 s u p e r h e a t f r i c t i o n 1 e n t r o p i c c o m p r e s s i o n entropic compression with intercooling pressure loss subcooling 2 3 4 Real Process Refrigeration Cycles Page 1 Refrigerants should have the following characteristics: I. Thermodynamic: o High h fg o Low freezing temperature o High critical temperature o Positive evaporating pressure o Low condensing pressure II. High dielectric strength of vapor o Good heat transfer characteristics o Satisfactory oil solubility o Low water solubility o I nertness/stability III. Safety: o Nonflammability o Nontoxicity o Nonirritability I. Environmental o Ozone depletion o Global Warming...
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This note was uploaded on 06/20/2009 for the course THERMO n/a taught by Professor N/a during the Spring '09 term at Abraham Baldwin Agricultural College.
- Spring '09