Simulation study on compression characteristics of low GWP refrigerants in the cylinder of rotary compressors

Abstract

Abstract Using low GWP(Global Warming Potential) refrigerants in the air-conditioning system to replace the conventional refrigerant R22 is an important strategy to ease global warming. The energy consumption of air conditioning systems is primarily determined by the compression characteristics of refrigerant in the cylinder of the rotary compressor. In this paper, a mathematic model of refrigerant compression in the cylinder is developed, which considers leakage, heat exchange between refrigerant and the wall and refrigerant solution in the oil. The performance of the rotary compressor using refrigerant R290, R1270, R32 and R22 is contrastively discussed by using simulation methods. Results show that the rotary compressor using R290 has highest COP and lowest power consumption under the same cooling condition. The COP of R290 at the outdoor temperature of 45 ℃ is 9.5% higher than that of R1270. The volume efficiency of R290 at the outdoor temperature of 50℃ is 5.1% greater than that of the R32. The indicated efficiency of R290 at the outdoor temperature of 40℃ is 4.0% greater than that of the R1270. The discharge, leakage and heating are the main factors that cause the loss of indicated efficiency. Refrigerant leakage and high solubility in the oil are the main reasons for the low volume efficiency of R32 and R1270 respectively. The discharge, leakage and heating are the main factors that causes the loss of indicated efficiency.