OPTIMIZATION OF THE SPECIFIC RATE OF REFRIGERATION IN COMBINED REFRIGERATION CYCLES

The optimization problem of a combined refrigeration cycle formed by t wo endoreversible Carnot refrigeration cycles in series without interm ediate reservoirs has been studied using finite-time thermodynamics. T he fundamental relation between cooling quantity and coefficient of pe rformance (COP) of the combined cycle is derived for a general physica l model of a combined cycle. Relations are derived between the SROR (= optimal specific rate of refrigeration, i.e. the average rate of refri geration per unit of total heat-transfer surface area) and the COP for a piston-type, stable flow model of combined cycles. Our results may be extended to an endoreversible, combined refrigeration cycle formed by more than two endoreversible Carnot refrigeration cycles.