Process design and evolutionary algorithm optimization of a biomass-based energy system to produce electricity, heating, and cooling

Abstract

This research presented and thoroughly examined a combined energy system that incorporates a gas turbine cycle, a supercritical CO2 cycle, and a Stirling engine in this respect. To make better use of the energy and exergy introduced to the system via biomass, other systems and components are added, which in turn served to increase the complexity of the system. In the combustion chamber, biomass is employed as a fuel, and four different materials are examined. The examination of the CHP-SE system is based on energy, exergy, and economic analyses. Multi-objective optimization is used to find the best-operating conditions, taking into account both thermodynamic and economic factors. The Paddy husk has the best energy and exergy efficiency, with 79 percent and 42.4 percent, respectively, while having the most CO2 emission of the three fuels, with 0.8 t/MWh. Gasifier and combustion chambers account for more than 80% of exergy destruction. Exergy efficiency and cost rate under ideal circumstances are 40.75 percent and 65.78 $/h, respectively, according to the multi-objective results. The overall thermal and exergy efficiencies of the overall system are in the range of 54–56% and 29–32%, respectively. The efficiencies for the air–gas cycle are in the range of 54–56% and 32–35% and for the supercritical CO2 cycle are 100% and in the range of 73–75%, respectively. It must be noted that thermal efficiency is defined as the useful output energy (including the thermal output of the system) to the thermal input energy. As all the thermal energy transferred to the S–CO2 cycle is used either as work or heat, this cycle’s thermal efficiency is calculated as 100%.