Theoretical and technical analysis of the photo-thermal energy cascade conversion for fuel with high-temperature combustion

This study theoretically reveals the advantages of the photo-thermal energy cascading conversion over single thermal energy or a radiative energy conversion. It also analyzes the potential of the photo-thermal energy cascading conversion relying on typical power generation units with different parameters and considers the research outlook. The results demonstrate that the cascade conversion is more critical for high-temperature conditions since there are limitations for single radiation energy; thus, oxy-fuel combustion at a high tempera-ture is more suitable. In consideration of technology conditions, the cascade system based on ultra-supercritical units can theoretically increase efficiency by more than 20% points under oxy-fuel combustion, whereas the efficiency of the cascade system based on combined cycle units can be theoretically increased by 15% points. The efficiency of the cascade system based on the small-parameter organic Rankine cycle unit can be increased by over 30% points according to the actual technology, and the small-scale unit could be applied in distributed energy systems. It is also pointed out that the further improvement of the system lies in the design of staged thermo-photovoltaic and complex thermal cycles to realize the cascade utilization of photo energy or thermal energy.

Automated summary

This study reveals the advantages of photo-thermal energy cascading conversion over single thermal energy or radiative energy conversion. It analyzes the potential of the cascade conversion with different power generation units and considers future research outlook. The results show that cascade conversion is critical for high-temperature conditions, with oxy-fuel combustion being more suitable. Depending on the technology conditions, efficiency can be increased by more than 20% points for ultra-supercritical units, 15% points for combined cycle units, and over 30% points for small-parameter organic Rankine cycle units.