Development of a Hermetically Sealed Stirling Engine Battery Charger

Abstract

Recent Stirling engine research at the University of Canterbury has focused on the development of a compact 12 volt 200 watt electrical battery charger suitable for use in yachts, mobile homes or remote dwellings, and intended for scaling up to larger power applications. The hermetically sealed engine with integral alternator uses a four-cylinder double-acting configuration with air pressurized to 1 MPa as the working fluid. The engine and battery charger control system includes self-regulation, and automatic start and shut-down. The previous paper has described the wobble yoke mechanism which is central to the engine design as it requires only pre-lubricated single degree of freedom bearings. This paper explains the design philosophy behind the new engine and describes the computer modelling and subsequent development of engine components on an alpha configuration experimental prototype. Features examined include the alternator, the cylinder-mounted seals and the heat exchangers. Embodiment design features of the final double-acting prototype are discussed. Performance data for the experimental prototype are presented.