Thermodynamic and Multi-Objective Performance Optimization of an Integrated ORC–VCR System Powered by Low-Grade Waste Heat

Abstract

Abstract. The recovery and utilization of low-grade waste heat offer a pathway to enhance energy efficiency. Mitigate greenhouse gas emissions and reduce dependence on fossil fuels. This study presents a numerical thermodynamic investigation, supported by validation with published experimental data, of an integrated organic Rankine cycle—vapor compression refrigeration (ORC–VCR) system. The system couples the ORC and VCR through a turbine–compressor assembly on a common shaft, with a 60 kW heat source supplying energy at 348 K. Simulation results indicate a power loop efficiency of 5.15%, a coefficient of performance of 4.105, and a cooling capacity of 10.85 kW under design conditions. Exergy analysis shows declining efficiency with increasing source temperature, while R1233zd(E)–R1233zd(E) demonstrates superior thermophysical performance. Multi-objective optimization genetic algorithm identified operating conditions that balance exergetic efficiency and cooling effectiveness, with ambient temperature emerging as the most critical parameter. Beyond theoretical insights, the findings highlight the system's potential for industrial waste heat recovery and sustainable cooling applications, particularly in sectors such as manufacturing and energy-intensive processing. Future research should integrate economic and environmental assessments to accelerate the deployment of ORC–VCR systems in real-world ultra-low-grade heat recovery scenarios.