Experiments on the Performance Evaluation of Heat Pump Cycle using CO_2 Based Binary Refrigerant Mixture

摘要

In the present study, the cycle performance of heat pump system using CO_2 based binary refrigerant mixtures has been investigated experimentally. The main component of binary refrigerant mixtures is CO_2, while the second component of the mixture is selected from three kinds of refrigerant: DME (di-meihyl ether), R1234ze(E) (trans-l,3,3,3-tetrafluorpropene) and R32. Experiments to evaluate cycle performance for the three kinds of CO_2 based binary refrigerant were carried out in three operating modes: water heating, air heating and air cooling modes, where the heating/cooling capacity and the degree of superheat at the evaporator outlet were kept constant in each mode and the charge amount of refrigerant was changed to find the maximum COP (coefficient of performance). Then, the effects of the second component on COP were examined in each operating mode.