Power Generation Using Low Temperature Differential Stirling Engine Technology

Abstract

A global paradigm shift in power generation towards sustainability and low environmental impact has driven associated research. Many possible power generation technologies exist, and no single technology will satisfy all (or even most) generation requirements. A Stirling engine based power generation system is being investigated for the potential economic use of low-grade (low enthalpy) heat (sub 1000 C), especially from remote geothermal sources where the heat can not be used in direct applications.
A 500 W prototype Stirling engine system has been designed to begin determining the potential viability of using low enthalpy heat sources, where temperature differentials may be as low as 300 C, for practical power generation. The design methodology has utilised the modified Beale Number, preliminary numerical modelling, and fin-tube heat exchanger approximations. The result is a novel gamma-type engine configuration capable of being pressurized to 1 MPa. Being a research prototype, important engine parameters such as displacer piston velocity profile, piston phasing, and those associated with the regenerator matrix, are able to be varied in order to optimise engine performance.