Preliminary Investigation of an Up-Scaled Gamma-Type Stirling Engine for Power Production

Abstract

This paper presents the development of Gamma-type Stirling engine for High Temperature Differential (HTD) and self-pressurized mode of operation. The engine is the up-scaled version from the Low Temperature Differential (LTD) miniaturized gamma-type Stirling engine. The test engine is featured with 85cc power piston and 4357cc displacer piston swept volumes, respectively. The characterization of few critical engine parameters and components that includes heater head section, cooler section, displacer and power pistons material selection and heat source system had been conducted. Air is used as a working fluid and Liquefied Petroleum Gas (LPG) is utilized as the heat source in order to cater for the heater temperature up to 1000°C. The workability test of the engine revealed that the lightweight in mass of the displacer piston and the auxiliary cooling effect at the cooler section had contributed to a significant improvement on the engine rotational motion. The static load test determined that the engine is capable of producing the friction power of 1.2W for stainless steel mesh wire displacer and 0.3W for polystyrene displacer. Based on Beale formula, the estimated power of 4W can be produced by the engine using stainless steel mesh wire displacer and 2.4W of power using polystyrene displacer. Good agreement has been shown, where the potential net power production of 3.8W and 2.1 W for stainless mesh wire displacer and polystyrene displacer, respectively. Further investigation is needed to improve the heat regeneration in between hot and cold sections of the engine to realize the sustainable performance of the engine at higher range of temperature difference and output power.