Waste heat recovery of a combined regenerative gas turbine - recompression supercritical CO2 Brayton cycle driven by a hybrid solar-biomass heat source for multi-generation purpose: 4E analysis and parametric study

Abstract

This study substantiates that the waste heat of a combined regenerative gas turbine cycle (GTC) and recompression supercritical CO2 Brayton cycle (SCBC) driven by a hybrid solar-biomass heat source can be effectively recovered via combining various subsystems encompassing a thermoelectric generator, an LiBr–H2O absorption refrigeration system, a heat recovery steam generator, and a proton exchange membrane electrolyzer with the cycle. The environmental and exergoeconomic performances of the system under a base case are compared between a hybrid solar-biomass mode (with direct normal irradiance (DNI) of 0.8 kW m−2) and biomass-only mode (while DNI is lower than 0.4 kW m−2). The results indicate that the employment of the solar power tower results in slight reductions in environmental impacts, while significant diminutions in thermodynamic and economic performances. For hybrid and biomass-only modes, the total energy efficiency of the system correspondingly improves by 22.48 and 29.6% points and the total exergy efficiency of the system respectively enhances by 6.18 and 7.6% points thanks to recovering the waste energy from the regenerative GTC - recompression SCBC via the proposed systems, while the utilized subsystems in the two mentioned modes respectively account for merely 5.1% and 8.1% of the system total cost rate.