Performance of some zeotropic mixtures as alternative refrigerants to R22 and R502

Abstract

Many zeotropic refrigerant mixtures are being proposed as alternatives to CFCs and HFCFs refrigerants that are being phased out. The main advantage in the use of zeotropic mixtures is the possibility of reduction in entropy generation in the condenser and evaporator by matching the glides of refrigerant and heat transfer fluid. Glide matching is difficult with some zeotropic mixtures due to the nonlinear variation of enthalpy with temperature during phase change. Also, there is a distinct possibility of formation of pinch points with some mixtures, resulting in entropy generation. In this paper, the performance of four mixtures of R32, R134a, R125, R143a and R23 are studied as alternatives to R22 and R502 from thermodynamic as well as temperature pinch points of view. The results demonstrate the importance and the need for pinch point analysis in the evaluation of alternative zeotropic refrigerant mixtures. © 1998 John Wiley & Sons, Ltd.