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

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. (C) 2021 Published by Elsevier Ltd.

Automated summary

This study demonstrates that combining solar and biomass heat sources can effectively recover waste heat and improve system efficiency and exergy efficiency.