Abstract
A Stirling engine with a single multi-phase working fluid for getting high specific power and high thermal efficiency is thermodynamically studied and proposed. The Stirling engine with supercritical heat recovery process can decrease the high-pressure level of working fluid from common gaseous Stirling engines. The thermal efficiency with three different working fluids of (SF)_6,C_3H_8 and R125 is calculated and the calculated thermodynamic efficiency is found to sufficiently approach the Curzon and Ahlborn efficiency that is drawn from entropy generation minimization of power cycle.