Abonnement à la biblothèque: Guest

ISSN Online: 2377-424X

ISBN Print: 0-89116-909-1

International Heat Transfer Conference 9
August, 19-24, 1990 , Jerusalem, Israel

THE IMPACT OF HEAT TRANSFER MODE ON THE EFFICIENCY OF HEAT ENGINES OPERATING AT MAXIMUM POWER

Get access (open in a dialog) DOI: 10.1615/IHTC9.1410
pages 329-334

Résumé

The analysis of irreversible heat engines within the framework of finite-time thermodynamics has essentially been restricted to Newtonian (linear) heat conduction only. We show that the functional temperature dependence of heat transfer has a significant impact on the performance of the general class of cyclic endoreversible heat engines, in particular on their efficiency at maximum power. The results are illustrated for the cases of radiative heat transfer and conductive heat transfer as modeled by irreversible thermodynamics. We prove that efficiency at maximum power is in general not independent of the heat transfer coefficients (as had been concluded for heat engines with Newtonian heat conduction), and that a type of symmetry exists relative to the functional temperature dependence of Newtonian heat conduction. The "Curzon-Ahlborn" efficiency of finite-time thermodynamics is shown not to be a fundamental upper limit on the efficiency of an endoreversible engine at maximum power point. Rather, this limit depends both on the functional temperature dependence of the heat transfer and on the relative value of the hot and cold side heat transfer coefficients.