Energy and exergy analyses of a coal-fired micro-CHP system coupled engine as a domestic solution

Abstract

In this study, a coal-fired stoker boiler and a beta-type rhombic-drive Stirling engine were manufactured and tested. The performance of the coal boiler with a Stirling engine has been investigated experimentally for the heating system of a three-storey house. The aims of this study are to investigate the Stirling engine's electricity generation potential and thermal energy production. Also, energy and exergy analyses of the micro-CHP system were performed to evaluate thermodynamic performance. Measurements were taken at 10-min intervals for three months. Thus, the temperature values, thermal power, thermal performance, efficiency, energy rates, exergy rates, and electrical parameters of the micro-CHP system can be monitored. The heating demand of the building was covered totally by the micro-CHP system, and the thermal power of the stoker boiler was reduced by approximately 1.29 kW due to the integration of the Stirling engine. The daily total of 2.6 kWh of electricity was generated with the Stirling engine and stored in the battery, and the rest of the electrical energy demand was taken from the grid. If the heating system is supported by PV, it can be operated off-grid. This study will provide insight into the usage of micro-CHP systems in residential applications.