Experiments on the Performance Evaluation of Heat Pump Cycle using CO₂ Based Binary Refrigerant Mixture

Abstract

In the present study, the cycle performance of heat pump system using CO₂ based binary refrigerantmixtures 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-methylether), R1234ze(E) (trans-1,3,3,3-tetrafluorpropene) and R32. Experiments to evaluate cycle performancefor the three kinds of CO₂ 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 theevaporator outlet were kept constant in each mode and the charge amount of refrigerant was changed to findthe maximum COP (coefficient of performance). Then, the effects of the second component on COP wereexamined in each operating mode.