In order to study the heat transfer characteristics of the low-temperature organic Rankine cycle(ORC)and obtain the optimum refrigerant mixtures

this paper select R245fa+cyclohexane as the component of mixed fluid to establish numerical model for the evaporator.By analyzing the optimal outlet temperature and exergy loss ratio of the flue gas under conditions with different mixed fluids

the optimal gas temperature at different compositions and the optimal performance refrigerants were ascertained.The results show that

the mixture with different compositions has different optimum gas temperature.When the mass ratio of R245 fa to cyclohexane in the mixed fluid equaled 0.56∶0.44

the fluid's exergy loss was the minimum and the heat transfer process was the closest to the ideal heat transfer.