Heat Pump System with R 22/R 114 Mixtures as Working Fluid (1st Report, Effects of Refrigerant Composition and Heat Source Condition on COP)

Abstract

The performance of a heat pump system is tested using an R 22/R 114 refrigerant mixture of 0, 50, 75 and 100 mol% R 22 as the working fluid. Double pipe counterflow heat exchangers of 12 m in length with a smooth inner tube of 22.4 mm I. D. are used for the condenser and evaporator. The effects of inlet temperature, temperature change and flow rate of the heat source water and heat load on COP are clarified. The COP for the mixture is found to be lower than that for pure refrigerant because of the lower heat transfer coefficient in condenser and evaporator. However, a trial calculation shows that the COP of the mixture becomes higher than that of pure refrigerant in the case of a large change in the water temperature if the heat transfer coefficient is twice as large as that of the experimental value and the superheating of the refrigerant is zero at the exit of the evaporator. © 1991, The Japan Society of Mechanical Engineers. All rights reserved.