Influence of sinusoidal motion on Stirling engines

Abstract

Stirling engines have a high potential to produce renewable energy due to their ability to use a wide range of sustainable heat sources and their high theoretical efficiencies. They have not yet achieved widespread use and commercial Stirling engines have had reduced efficiencies compared to their ideal values. This work shows that a substantial\ amount of the reduction in efficiency is due to the operation of Stirling engines using sinusoidal motion and quantities this reduction. A discrete model was developed to perform an isothermal analysis of a 100cc alpha-type Stirling engine with a 90_ phase angle offset, to demonstrate the impact of sinusoidal motion on the net work and thermal efficiency in comparison to the ideal cycle. The model was adapted to analyze beta and gamma-type Stirling configurations, and the analysis revealed similar reductions due to sinusoidal motion. Lastly, a mechanically plausible arrangement is presented and analyzed to demonstrate that non-sinusoidal operation can be accomplished.