Research on a new type of solar dish Stirling cogeneration system based on adjustable receiver and control strategy

Highlights: • A novel adjustable dual receiver for dish-Stirling cogeneration system is proposed. • A new accurate formula to calculate the focal spot diameter is proposed. • Control strategy of generation and heating switching based on irradiance is built. • Technical and economic indicators of the cogeneration system are evaluated. • Comprehensive energy efficiency can be increased by 55.83%. With the increasing global demand for carbon emission reduction, solar energy has received great attention worldwide, with solar dish Stirling system as a representative technology. However, some shortcomings of the conventional design limit its commercial application. In this paper, a novel solar dish Stirling cogeneration system (SDSCS) with adjustable dual receiver is proposed. A control strategy for switching between power generation and heat production modes is established, which is based on direct normal irradiance (DNI). In order to verify the system performance, three regions with significant differences in DNI levels in Tianjin, Yinchuan, and Lhasa were selected for comparison of technical and economic indicators. The results show that, compared with the conventional system that can only generate electricity, the SDSCS can achieve a significantly higher proportion of system running time in three regions at 14.66%, 24.53%, and 34.32%, respectively. The comprehensive energy efficiency shows the same trend at 55.83%, 53.91%, and 41.03%. In addition, the load satisfaction rate calculated by the day of the three regions is 43.05%, 81.46%, and 94.04%, respectively. In terms of levelized energy cost, the value of using SDSCS is 6.77 CNY/(kW·h), 3.37 CNY/(kW·h), and 1.94 CNY/(kW·h), lower than conventional system except for Tianjin.