OPTIMUM DISTRIBUTION OF HEAT EXCHANGER INVENTORY FOR COOLING LOAD DENSITY OPTIMIZATION OF A REAL BRAYTON REFRIGERATOR

摘要

The performance optimization of a regenerated Brayton refrigeration cycle with variable-temperature heat reservoirs is carried out by taking the cooling load density, i.e., the ratio of cooling load to the maximum specific volume in the cycle, as the optimization objective in this paper. The irreversible losses considered include the heat resistance losses in the hot- and cold-side heat exchangers and the regenerator, the irreversible compression and expansion losses in the compressor and expander, and the pressure drop losses in the piping. The analytical relations about cooling load density and coefficient of performance of the cycle are derived. The effects of pressure ratio, the allocation of heat exchanger inventory and heat capacity rate matching between the working fluid and the heat reservoirs on the cooling load density of the refrigerator are shown by detailed numerical examples.