Multi-aspect investigation and multi-criteria optimization of a novel solar-geothermal-based polygeneration system using flat plate and concentrated photovoltaic thermal solar collectors

This study investigates different aspects of an innovative multi-heat recovery-based solar-geothermal polygeneration system, acclaiming the exergetic, exergoeconomic, and energetic concepts. Principally, using two renewable energy sources, the whole framework of the system encompasses Concentrated PhotoVoltaic Thermal (CPVT) solar collectors, Flat Plate Solar Collectors (FPSCs), geothermal wells, an Ejector Refrigeration Cycle (ERC) Organic Rankine Cycle (ORC) integrated with a Solid Oxide Electrolyzer Cell (SOEC), heating production units, an air dryer, and an Organic Rankine Cycle (ORC) unit. Afterward, the sensitivity analysis utilized for the parametric study makes a multi-aspects optimization in diverse scenarios in which NSGA-II, as well as, fuzzy TOPSIS and fuzzy VIKOR decision makings, are handled to designate the optimal solution. The suggested system has professionally been devised thanks to the characteristic of maximum use of energy of the streams circulated. Hence, crucial variables evaluated are more influenced by the variation in the geothermal heater pinch point temperature gradient. Also, in the optimization scenario based on unit cost of products / exergy efficiency, the TOPSIS selects the optimal objectives of 4.29%/1.13 $/GJ, while the VIKOR selects 4.06%/1.07 $/GJ, respectively.