Design guideline for multi-cylinder-type liquid-piston Stirling engine

Abstract A multi-cylinder-type liquid-piston Stirling engine (MCLPSE) is an external combustion engine characterized by a low operation temperature difference below 100 K, a simple structure consisting of only a few parts, and the use of harmless working fluids, namely, air and water at atmospheric pressure. Although the structure is simple, the design method has not been established to date. This study proposes a systematic design guideline for the MCLPSE to attain a target output power under a given temperature condition. The guideline is based on the analysis of the natural mode oscillations of the system, the results of a thermoacoustic theory, and a simple heat transfer model of heat exchangers. The designed MCLPSE was numerically verified using a simulation code (DeltaEC). We introduced a linear alternator based on electromagnetic induction to extract the output power from the designed engine. The results showed that the designed engine achieved the target output power of 102 W under the heat source and sink temperatures of 130 °C and 23 °C, respectively.