Analysis of a dual-purpose refrigerating and heat pump system

Abstract The study is looking for the optimum configuration of a system that requires refrigeration and heating. An ammonia refrigerator separated from a R152a heat pump are first considered. Water is the hot carrying fluid. Based on the exergy analysis, that points out the location and magnitude of each system operational malfunction, an optimization strategy is considered. Following the optimization procedure the two initial separated systems are coupled by using the condenser of the refrigerating unit to preheat water. Due to the exergy destruction in the water preheating condenser, ammonia is replaced by CO2. The transcritical CO2 heater diminish the exergy destruction with the heat transfer across a finite temperature difference. Solutions for further improving the efficiency of the dual-purpose system focus on the decrease in the throttling valve destruction in the CO2 refrigerating unit.