Abstract
ON p. 326 of NATURE for August 29 appears an abstract of a paper by Dr. J. S. Haldane, which he read before the Institution of Mining Engineers on June 16. In this paper he has “thrown to the winds” the usual academic teaching in regard to the efficiency of a Carnot cycle, and has put forward a claim that another cycle has a greater efficiency. This, which for brevity we will call the Haldane cycle, consists of an adiabatic expansion BC (Fig. 1) followed by an isothermal compression CA and a constant volume heating AB. In the discussion on the paper, I proved that this cycle has only about half the efficiency of a Carnot cycle working between the same limits of temperature. This proof did not make use of Carnot's principle, but required only a knowledge of the thermal properties of air, which was treated as a perfect gas. In such a case it is perfectly easy to calculate the work done and the heat changes and therefore the efficiency.
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PORTER, A. Carnot's Cycle and Efficiency of Heat Engines. Nature 116, 497 (1925). https://doi.org/10.1038/116497a0
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DOI: https://doi.org/10.1038/116497a0
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