Design, multi-aspect analyses, and multi-objective optimization of a biomass/geothermal-based cogeneration of power and freshwater

Abstract

Proposing an effective multi-source plant is a promising approach to achieving higher performance in energy systems. By utilizing multiple energy sources, such as renewable and conventional sources, synergistically, a multi-source plant can enhance system efficiency, reliability, and sustainability. This paper presents a novel combination of a gas turbine cycle and a geothermal system for power and freshwater production, where the gas turbine cycle is an integration of modified methane and biomass-based systems. The proposed plant aims to improve the performance of conventional systems by considering thermodynamic, economic, and multi-objective optimization perspectives. Energy, exergy, and economic analyses are applied to assess the system's performance. Two double-objective optimizations are carried out to obtain the system's operation mode at the optimum state. The results reveal that the combustion chamber has the highest exergy destruction rate by 2967 kW. At the base operation conditions, the design system provides 5601 kW of net power, a freshwater production rate of 10.05 kg/s, and 39.5% of exergy efficiency. Furthermore, considering the net power-freshwater production rate as the optimization scenario, the optimum of 7070.52 kW net power and 41.16% exergy efficiency. While, considering exergy efficiency-exergy destruction as the objective scenario, the best payback period is obtained to be 5.71 years.