Development of a theoretical decoupled Stirling cycle engine

Abstract

The Stirling cycle engine is gaining increasing attention in the current energy market as a clean, quiet and versatile prime mover for use in such situations as solar thermal generation, micro-cogeneration and other micro-distributed generation situations. A theoretical Stirling cycle engine model is developed. Using a theoretical decoupled engine configuration in which working space swept volume, volume variation, phase angle and dead space ratio are controlled via a black-box electronic controller, a model is developed that is to be used as a tool for analysis of the ideal Stirling cycle engine and the limits on its real-world realisation. The theoretical configuration approximates the five-space configuration common in Stirling cycle analysis. It comprises two working spaces and three heat exchangers: hot side, cold side and the regenerator between. The kinematic crank mechanism is replaced by electronically controlled motor/generator units, with one motor/generator controlling each of the working pistons. The use of stop valves permits the flow and non-flow processes inherent in the ideal cycle to be realised. The engine configuration considered here is not intended as a viable prime mover but rather a tool for study of the limitations of the cycle.