A GENERAL PROPERTY OF ENDOREVERSIBLE THERMAL ENGINES

In this work we propose that endoreversible Carnot-type heat engines h ave a general property independent of the heat transfer law used to de scribe heat exchanges between the working fluid and its thermal reserv oirs. This property has to do with the so-called ecological function [ F. Angulo-Brown, J. Appl. Phys. 69, 7465 (1991)]. According to this pr operty, the efficiency at the maximum of the ecological function is th e semisum of the Carnot and the maximum power efficiencies for any hea t transfer law. This result is obtained by using the quasiparabolic be havior of power versus efficiency. From this property, we obtain a cor ollary over a general quantitative relation between the power (and als o the entropy production) of both maximum power and maximum ecological regimes. We also discuss a criterion to find the best ecological func tion. (C) 1997 American Institute of Physics.