A novel multi-generation system for sustainable power, heating, cooling, freshwater, and methane production: Thermodynamic, economic, and environmental analysis

Addressing environmental concerns and developing efficient systems pose significant challenges for researchers. This paper presents a groundbreaking multi-generation system designed to generate power, heating, cooling, freshwater, and methane. The system comprises a flash-binary power plant, a modified transcritical CO2 cycle, a proton exchange membrane electrolyzer, and a methanation unit. Integration of the modified transcritical CO2 cycle with the ejector refrigeration cycle, solar still desalination unit, and heating unit enhances its functionality. The proton exchange membrane electrolyzer supplies hydrogen to the methanation unit. The thermodynamic, economic, and environmental approaches are employed to analyze the system, and three scenarios are considered to assess the optimum state. Accordingly, the exergy efficiency, products' total cost, and exergoenvironmental impact rates are obtained at about 28.30%, 4.153 $/h, and 73.48 mPts/h, respectively. The gas heater unit has the highest exergy destruction rate and cost rate and exergoenvironmental impact rate by 37.6%, 36.4%, and 22.7% portions, respectively. The optimal state provides 33.25% exergy efficiency, 450.9 kW net power, 10.07 kg/h freshwater, and 2.149 kg/h methane. The cooling and heating production rates are attained 28.16 kW and 183.5 kW. The product's cost rate and exergoenvironmental impact rates are estimated at about 4.357 $/h and 76.64 mPts/h.