PERFORMANCE EVALUATION OF A HEAT-PUMP CYCLE USING NARMS BY A SIMULATION WITH EQUATIONS OF HEAT-TRANSFER AND PRESSURE-DROP

Simulation analyses for a vapour compression heat pump cycle using non azeotropic refrigerant mixtures (NARMs) of R22 and R114 are conducted under the condition that the heat pump thermal output and the flow rat e and inlet temperatures of the heat sink and source water are given. The heat transfer coefficients of the condensation and evaporation are calculated with empirical correlations proposed by the authors. The v alidity of the evaluation method and the correlations is demonstrated by comparison with experimental data. The relations between the coeffi cient of performance (COP) and composition are shown under two conditi ons: (1) the constant heat transfer length of the condenser and evapor ator; and (2) the constant temperature of refrigerant at the heat exch anger inlet. The COP of the NARMs is higher than that of pure refriger ant when the heat transfer lengths of the condenser and evaporator are sufficiently long.