Design and optimisation of a novel solar-driven ORC-based polygeneration system with hybrid PVT, cascade refrigeration, and PEM electrolysis

This study presents the design, modelling, and optimisation of a novel zero-emissions polygeneration system fully powered by renewable energy sources. A new integration approach supported by an advanced optimisation framework is proposed to enhance the thermodynamic performance and overall efficiency. The system uniquely combines a hybrid Photovoltaic-Thermal (PVT) powered Organic Rankine Cycle (ORC) employing flexible Perovskite Solar Cell (PSC) technology, a double-effect compression-absorption refrigeration subsystem, and hydrogen production via a Proton Exchange Membrane (PEM) electrolyser. The cascading configuration maximises energy utilisation by recovering low-grade thermal energy, promoting synergistic operation, enabling simultaneous multi-carrier generation, and reducing exergy losses compared to standalone systems. Its applications are particularly relevant for both buildings and energy-intensive industrial processes, where integrated renewable solutions can provide high efficiency, flexibility, and emission-free operation. An advanced hybrid optimisation methodology coupling an Artificial Neural Network (ANN) with a multi-objective genetic algorithm is applied to identify optimal configurations through performance-cost trade-offs. For a three-objective function, the optimum design achieves an exergy efficiency of 19.1 %, net power output of 69.6 kW, and a cost rate of $ 14.2/h. Over a 20-year operation period, the system shows strong economic viability, yielding a payback period of 5.7 years, a Net Present Value (NPV) of $602,000, and an Internal Rate of Return (IRR) of 11.6 %.