Edinburgh Napier University

  The Stirling cycle engine of 1816 and subsequent closed cycle regenerative heat engines have been the subject of many analyses. The complex nature of the mechanical, fluid, and thermal processes within the engine makes an accurate analysis challenging. In describing engine performance and operation, methods thus far employed have considered idealised cycles, combined cycles, empirical data and finite element techniques to predict engine performance. This paper presents a third order analysis of a low temperature differential Ringbom Stirling engine [1] undertaken at Napier University Edinburgh. The laws of conservation of mass, momentum and energy, as well as the ideal gas law, are applied to each space and element in the engine, and a numerical model is developed. The numerical model describes the variation of the kinematic, fluid and thermal processes within the engine with time, and will be used to optimise the engine design. A physical model will be used to obtain operational data. The preliminary analysis suggests that in respect of optimising a physical engine several approaches may be adopted. The optimised physical engine, coupled with an electric generator or pump will to exploit energy sources such as process waste heat, solar hot water and geothermal low grade heat.