PARAMETRIC STUDY OF VAPOUR-COMPRESSION VAPOUR-ABSORPTION CASCADE REFRIGERATION SYSTEM

Abstract

The study carried out to analyse a refrigeration system in cascade with a compression system at the low temperature stage and an absorption system at the high temperature stage to generate cooling at low temperatures. NH3 has been considered as refrigerant in the compression stage and the pair LiBr–H2O in the absorption stage. The analysis has been realized by means of a mathematical model of the refrigeration system implemented in a computer program and the study also carried out the effect of efficiency of the condenser-evaporator heat exchanger on the COP of the cascade system. The intermediate temperature level is an important design parameter that causes an opposite effect on the COP of the compression and absorption systems. Therefore, the cascade system COP presents a maximum when the intermediate temperature is varied. The intermediate temperature that produces the maximum COP depends on the evaporation temperature of the compression system.