OPTIMAL CONFIGURATION OF A CLASS OF 2-HEAT-RESERVOIR REFRIGERATION CYCLES

The optimal coefficient of performance (COP) of a class of two-heat-re servoir refrigeration cycles can be determined by a given cycle time a nd absorbed heat (cooling load) with consideration of heat leak, finit e heat capacity low-temperature source and infinite heat capacity high -temperature heat sink. The refrigeration cycles considered in this pa per include (1) infinite low-and high-temperature reservoirs without h eat leak, (2) infinite low-and high-temperature reservoirs with heat l eak, (3) finite low-temperature source and infinite high-temperature s ink without heat leak, and (4) finite low-temperature source and infin ite high-temperature sink with heat leak. It is assumed that the heat transfer between the working fluid and the reservoirs obeys Newton's l aw. It is shown that the existence of the heat leak does not affect th e optimal configuration of a cycle with an infinite low-temperature so urce. The finite heat capacity of a low temperature source without hea t leak makes the cycle a generalized Carnot refrigeration cycle. There exists a great difference of the cycle configurations for the finite low temperature source with heat leak and the former three cases. More over, the relations between the optimal cooling load and the COP of th e former three configurations are derived, and they show that the heat leak affects the cooling load versus COP characteristics of the refri geration cycles. Published by Elsevier Science Ltd.