Stirling cycle cooling engine with two-phase, two-component working fluid

Abstract

A Stirling cycle cooling engine operates on a closed regenerative thermodynamic cycle with compression and expansion of the working fluid at different temperature levels. Conventional engines use a gaseous working fluid but a significant improvement in refrigerating capacity may be gained with a two-phase, two-component working fluid. This consists of a gaseous carrier and a component which is liquid in the cold region and gaseous in the ambient temperature spaces with the phase change occurring during the regenerative process. This causes an increase in the range of the pressure excursion of the working fluid and consequently increases the refrigerating capacity with no penalties in terms of size, weight, or cost. The degree of improvement depends on the particular design and operating conditions of the engine. The effects of variation of some of these parameters are explored.