Development of a Stirling engine powered by parabolic trough collectors

Abstract

Stirling engines are regaining their importance due to alternative energy challenges. In fact, they are currently being used in solar paraboloidal dish systems. Such systems are relatively bulky and therefore rather difficult to be implemented for domestic roof top purposes. In this paper a lower profile system consisting of a Stirling engine coupled to solar parabolic trough collectors was developed. The system has several advantages over a paraboloidal dish system that heats the engine directly. One such advantage is thermal storage potential which stores heat energy that can alternatively be used to generate electricity or provide auxiliary heating, depending on what is desired. The specifically designed prototype Stirling engine, SE-15, consists of a 150 mm square engine which is capable of developing 18W at an expansion space temperature of 220 °C and compression space temperature of 30 °C. This power output is quoted at a compression ratio of 1.34 and at atmospheric pressure conditions. Thermal energy is supplied to the engine by two parabolic trough collectors having an aperture of 1 m and a length of 3.2 m with a concentration ratio of 12.7.