Pinch point and maximum temperature difference may occur in heat exchanger because of the non-linear relationship between the temperature and enthalpy of the zeotropic refrigerant mixtures in the two-phase region.The discriminant used to identify the pinch point or maximum temperature difference was presented by Venkatarathnam,but the discriminant can not be used to identify all the kinds of zeotropic refrigerant mixtures.The modified discriminant used to identify the pinch point and maximum temperature difference was obtained in this paper,which was proved by analyzing two zeotropic refrigerant mixtures.The results showed the possible concurrence of pinch point and maximum temperature difference in the heat exchanger.
