Scrutiny of a Bi-evaporator poly-generation system includes distilled water production unit: Comparative study and Bi-objective optimization

Abstract

While geothermal energy is typically associated with beneficial environmental effects, it is crucial to acknowledge that it can lead to greenhouse gas emissions. Therefore, the implementation of geothermal systems should include an environmental assessment. This study presents and evaluates an innovative geothermal-powered bi-evaporator poly-generation system from seven perspectives: thermodynamic, extended-environmental, exergoenvironmental, exergoeconomic, net present value, and bi-objective optimization. The designed ploy-generation system comprises a desalination unit, a unit for extracting hydrogen, and a modified organic flash cycle, all integrated with a single geothermal flash cycle. These subsystems work in unison to create a comprehensive and integrated system for simultaneously generating purified water, green hydrogen, electricity, and meeting refrigeration load requirements. Regarding the findings at the base mode, the designed system is able to generate net power, refrigeration load, distilled water, and H2 production rates of 244.9 kW, 741.4 kW, 0.4443 kg/s, and 1.062 kg/h, respectively. By employing NSGA-II optimization, the values of commodities are substantially increased, which enhanced the poly-generation system product cost and energetic efficiency by 7.13 % and 30.48 %. Also, the net electricity selling price significantly affects NPV, so the payback period reduces to 8.56 years.