The Influence of Working Fluid on Stirling Engine Performance

Stirling engines are attractive closed-cycle reciprocating external heat engines that convert heat into mechanical work. In order to enhance engine performance, it is essential to choose the appropriate working fluid based on its physical and thermal properties. The aim of this paper is to investigate the impact of working fluid on the Stirling engine's performance. Different working fluids were studied (air, helium, and hydrogen) because they are the most common working fluids that are used in the developed Stirling engines. According to the results, hydrogen provides more power and higher thermal efficiency than helium and air, but hydrogen is a flammable gas that may cause explosions if not handled carefully. Therefore, most developed Stirling engines work better when charged with helium than with air due to its lower viscosity and higher thermal conductivity.