Reliable renewable power production by modeling of geothermal assisted solar chimney power plant

Abstract

The growing concern about the impact of climate change has highlighted the importance of renewable resources. Wind, geothermal, and solar energy are some of the most natural renewable energy sources, dominated by their availability and efficiency. Currently, medium-low enthalpy geothermal is exploited less than high-enthalpy geothermal resources. In addition, the variable nature of solar radiation is a significant problem for the solar systems resulting from the solar chimney power plant's discontinued operation. These geothermal resources can feed into the solar chimney power plant to generate electricity and resolve the solar system discontinuously. In the present research, a geothermal hot spring with a temperature of 75 °C in Khorasan, Iran, has been investigated as a case study. By developing a finite volume Computational Fluid Dynamics model, the system performance has been evaluated. Hybridizing these two energy sources declares a significant improvement in the power plant's performance. Increasing the thermal flux of hybrid systems by 200 kW/m2 designates a 17% increase in power generation of the geothermal-solar system at a specific hour of the day, in comparison with a stand-alone solar chimney. Moreover, a geothermal–solar chimney power plant in the coldest month of the year showed the same output power as solar chimney power plants could generate in the warmest month of the year. Annual averaged thermal flux productivity under the hybrid system is 585.12% larger than sole geothermal spring production. The hybrid system model produces 319.5 MWh while the stand-alone system generates 263.9 MWh of energy throughout the year. Economic analysis shows that the proposed system is one-tenth affordable considering energy prices in Iran.