Table of Contents
Journal of Thermodynamics
Volume 2011, Article ID 647937, 5 pages
Research Article

Substance Independence of Efficiency of a Class of Heat Engines Undergoing Two Isothermal Processes

Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands

Received 29 November 2010; Accepted 31 March 2011

Academic Editor: Y. Peles

Copyright © 2011 Y. Haseli. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Three power producing cycles have been so far known that include two isothermal processes, namely, Carnot, Stirling, and Ericsson. It is well known that the efficiency of the Carnot cycle represented by 1 𝑇 𝐿 / 𝑇 𝐻 is independent of its working fluid. Using fundamental relationships between thermodynamic properties including Maxwell's relationships, this paper shows in a closed form that the Ericsson and the Stirling cycles also possess the Carnot efficiency irrespective of the nature of the working gas.