THE ANALYSIS OF EXERGY EFFICIENCY IN THE LOW TEMPERATURE HEAT EXCHANGER

Based on the analyzing of the thermodynamic performance of the heat transfer process in the low temperature heat exchangers, the exergy efficiency of the heat transfer process is defined and a general expression for the exergy efficiency is derived, which can be used to discuss the effect of heat transfer units number and heat capacity ratio of fluids on the exergy efficiency of the low temperature heat exchanger. The variation of the exergy efficiency for several kinds of flow patterns in the low heat exchangers is compared and the calculating method of the optimal values of heat capacity ratio for the maximum exergy efficiency is given.