Conventional and enhanced thermodynamic and exergoeconomic analyses of a photovoltaic combined cycle with biomass post firing and hydrogen production

Abstract

Due to the finite nature of fossil fuels and their unsustainable function in the power production industry, a photovoltaic combined cycle with biomass post firing and hydrogen production is proposed and assessed with conventional and enhanced (avoidable and unavoidable) exergy and exergoeconomic analyses. It is observed that increasing the compressor pressure ratio increases the CO2 discharge rate, the system exergy destruction rate, and the exergoeconomic factor of the cycle, and decreases the exergy efficiency, the natural gas flow rate, the exergy destruction cost rate and the system unit product cost. Further, the energy efficiency is optimized by adjusting the compressor pressure ratio. Increasing the area of the photovoltaic thermal system decreases the energy and exergy efficiencies and increases the unit product cost of the system. Hydrogen injection to the combustion chamber is an alternative for using the product hydrogen. This operation decreases the CO2 discharge rate, the exergy destruction rate in the combustion chamber, the system product cost and the energy efficiency. A comparison of the results of conventional and enhanced analyses shows that they have different implications about the optimization of the post combustion chamber, the heat recovery steam generator, and the pump. With conventional analyses, the post combustion chamber and the pump should be considered for investment cost decreases and the heat recovery steam generator for quality improvement. But the enhanced analyses lead to opposite conclusions.