Energy and exergy analysis of solar organic Rankine cycle coupled with vapor compression refrigeration cycle using different working fluids

Abstract

This study investigates the performance of a solar-powered organic Rankine cycle (ORC) coupled with a vapor compression cycle (VCC) for simultaneous power generation and cooling applications in the region of Ghardaïa (Southern Algeria). The analysis focuses on the energy and exergy performance of five low-GWP refrigerants: R134a, R1234ze(E), R600a (isobutane), R152a, and R1234yf, under realistic operating conditions. In addition, key parameters such as turbine inlet temperature and pressure, VCC condensing and evaporation temperatures, and the VCC/ORC mass flow rate ratio were analyzed to evaluate their impact on net power output, cooling capacity, coefficient of performance (COP), and exergy efficiency. Results indicate that R600a provides the highest net power output (7.08 kW) and exergy efficiency (9.87%), making it ideal for power-dominant applications. R152a, on the other hand, excels in cooling performance, achieving a COP of 6.10. R1234ze(E) emerges as the most environmentally sustainable option, offering a balanced performance with 8.02% exergy efficiency and a negligible GWP of 7. Exergy analysis reveals that the solar collector is the primary source of irreversibility, with 58 kW of exergy destruction, followed by the ORC and VCC subsystems. These findings offer valuable insights for designing sustainable cogeneration systems in arid regions, highlighting the trade-off between thermodynamic performance and environmental impact when selecting the optimal working fluid for ORC-VCC applications.