Simulation analysis of a two rolling piston expander replacing a throttling valve in a conventional refrigerant heat pump system

摘要

An expander is employed to replace a throttling valve in a heat pump system of the conventional refrigerant in order to further improve the efficiency of the system by recovering partial expansion work to decrease energy consume of the system. Due to large expansion ratios of conventional refrigerants, a two-rolling piston one-stage expander was proposed and designed. Simulation analysis was developed by analyzing irreversible losses in the expansion work process. The simulation results show that, friction losses of a conventional refrigerant expander are 80.2% of total losses, which are the main factors to influence the efficiency of expander. Then the measures of reducing friction losses are presented, which would be expected to improve the expander efficiency efficiently.