Abstract: A general relation among the rate of profit, rate of pumping heat and coefficient of performance of a three-heat-source heat pump is given in this paper. By using it, the relation between the optimal rate of profit and coefficient of performance of an endoreversible three-heat-source heat pump is derived and the optimal criterion of the coefficient of performance is discussed. The conclusions obtained have a certain instructive meaning for the optimal design and the performance improvement of a class of three-heat-source heat pumps such as absorption heat pumps, chemical heat pumps, and so on.

Key words: Three-teat-source heat pump, Rate of profit, Eate of pumping heat, Coefficient of performance, Optimal criterion