The Joule cycle

Abstract

In the Joule cycle an enclosed gas flows continuously to and fro between a compressor and an expander, taking in heat in one direction and giving out heat in the other. These two processes of heat transfer can only be effected reversibly by cooling one external stream of fluid and warming another in unique proportions. The natural role of the ideal Joule cycle heat engine is thus the harnessing of a temperature difference between two supplies of fluid; the two streams can, in theory, be brought to a common temperature with the accompanying delivery, by the coupled compressor and expander, of the maximum possible work. The author shows the feasibility of (i) a Joule engine, taking heat from gases of combustion and pre-heating the air supply, and (ii) a Joule cycle heat pump.