Design and simulation of a geothermal–solar combined chimney power plant

•A geothermal–solar chimney power plant (GSCPP) is designed and analyzed.•Three different models, viz. full solar model, full geothermal model and geothermal–solar mode are compared.•Power generation under GSM is larger than the sum of FSM and FGM.•GSCPP can effectively solve the continuous operation problem of the SCPP.

The solar chimney power plant (SCPP) is dominated by the solar radiation, and therefore its discontinuous operation is an unavoidable problem. In this paper, low temperature geothermal water is introduced into the SCPP for overcoming this problem. Based on a developed transient model, theoretical analyses are carried out to investigate the performance of the geothermal–solar chimney power plant (GSCPP) with main dimensions the same as the Manzanares prototype in Spain. Three operation models, viz. the full solar model, the full geothermal model and the geothermal–solar combined model are compared in typical summer and winter days and throughout the year. It is found that the GSCPP can attractively run in the GSM to deliver power continuously. Due to the ambient-dependant geothermal water outlet temperature, introducing the geothermal water makes greater contribution in winter days than in summer days, in the night than in the daytime. Power generation under GSM is larger than the sum of FSM and FGM. GSM is not the simple superposition of FSM and FGM, but makes better utilization of solar and geothermal energy. In addition, introducing high temperature and mass flow rate geothermal water can doubled and redoubled improve the GSCPP’s power capacity.