A novel solar-driven waste heat recovery system in solar-fuel hybrid power plants

Abstract

Solar-fuel hybrid power generation can effectively reduce pollutants in fuel power plants and facilitate the efficient utilisation of solar energy. This study proposes a novel solar-driven waste heat recovery system for solar–fuel hybrid power plants. New system is integrated with parabolic-trough solar collector to drive the heat pump and optimise air pre-heating, offering unique advantages: solar energy amplification and upgraded utilisation. For a 600 MW unit, solar energy in new system generates an electric power of 9.0 MWe with a 0.67 % increase in thermal efficiency, almost twice that of conventional system. With waste heat recovery, the new system exhibits a solar-to-electricity efficiency of 42.12 %. The new system can increase boiler exergy efficiency from 47.78 % to 48.35 %, and decrease exergy loss of air pre-heating to 7.6 MWe. The essential energy saving mechanism of the new system can be attributed to the optimisation of air preheating. Owing to high thermal performance, new system can yield a net benefit of 13.82 million CNY/y, which is 2.6 times that of conventional system. The findings of this study can help for better understanding of solar energy amplification and and upgraded utilisation, thus opening new avenues for solar conversion in solar-fuel hybrid power generation systems.