A review of Stirling-engine-based combined heat and power technology

Abstract

Small- and micro-scale combined heat and power (CHP) technologies offer great potential for reducing energy costs and CO2 emissions in residential and small commercial buildings. Among various CHP technologies, Stirling engines, particularly free-piston ones, show great promise in residential applications because of their remarkable advantages of low emissions, maintenance, noise, and vibration, theoretically high thermal-to-electrical efficiency, and flexibility of fuel sources. This paper presents a comprehensive review of Stirling-engine CHP in terms of different heat sources, tri-generation systems, status of commercial development, techno-economic issues, and challenges and future trends. The techno-economic assessment indicates that the relatively low on-site operational efficiencies and considerable investment costs are the main issues that hinder the further development of Stirling-engine CHP systems, and suggestions for future development are made accordingly. For successful commercial dissemination of Stirling-engine CHP, it is essential to improve the on-site electrical efficiency, reduce the capital cost of systems, and develop renewable-energy-powered and free-piston Stirling-engine-based CHP systems against the background of grid decarbonization and carbon neutrality.