Thermodynamic and economic evaluation and optimization of the applicability of integrating an innovative multi-heat recovery with a dual-flash binary geothermal power plant

Generally, a stand-alone flash-binary geothermal power plant loses most of its input energy, so its efficiency declines accordingly. Its overall ability can be augmentable by utilizing structural modification and waste heat recovery leading to the most suitable exergetic performance with lower costs. On this account, the current paper suggests and investigates an innovative waste heat recovery for a dual-flash binary geothermal power plant. The integrated process consists of a Rankine cycle, a reverse osmosis desalination, and a proton exchange membrane electrolyzer. Here, two main processes, i.e., waste heat-to-power and power-to-hydrogen/freshwater, are regarded. Accordingly, the applicability of the system is examined from the energy, exergy, and economic points of view. Thus, a relevant sensitivity analysis is applied to the response variables where the effect of separator 2 pressure is more significant than other parameters. In addition, a non-dominated sorting genetic algorithm-II (NSGA-II) method is implemented to optimize the system thermodynamically and economically. The optimum state reveals an exergy efficiency of 43.83% and a levelized cost of products of 4.54 $/MWh. In this situation, the net output power and production rate of freshwater and hydrogen are estimated at 6474 kW, 22.51 kg/s, and 1.84 kg/h, respectively.