An innovative integrated system concept between oxy-fuel thermo-photovoltaic device and a Brayton-Rankine combined cycle and its preliminary thermodynamic analysis

Abstract

This study summarizes the guidelines for the quality-splitting utilization of the radiation and thermal energy after a brief review of the thermo-photovoltaic (TPV) technology and the power cycles. Based on this, an innovative concept of a system that integrates TPV technology and the Brayton-Rankine combined cycle (TBRC) is first proposed. The basic structure of the new system was modeled and a preliminary thermodynamic analysis was performed. The effects of the working conditions including the combustion conditions of different combustion atmospheres, the oxygen concentrations and fuels, and the cycle conditions of different pressures and working fluids on the TBRC system were investigated. It was found that the optimal pressure of the Brayton cycle in the system increased with the combustion oxygen concentration. The system output power was proportional to the combustion oxygen concentration. The system efficiency was similar under 21% O2/N2 conditions and 30% O2/CO2 conditions. The system efficiency was slightly higher for fuel oil than for methane. After considering the efficiency and environmental impacts, n-pentane was selected as the preferred organic Rankine cycle working fluid. Finally, we discuss the application and development prospects of the new system. It is determined that the oxy-fuel TBRC system with flue gas recycle and the integration between the cascade TPV technology and complex power cycles are future research directions.