Performance of compound parabolic collector integrated with organic Rankine cycle under low mass flow rates for clean energy

If the process heat of compound parabolic collector is integrated with an organic Rankine cycle, work output of significant amount from the system can be achieved provided mass flow rate of the organic fluid is properly maintained alongside uncontrollable ambient parameters. In this study, the objective is to analyse the performance of a low-concentration-ratio compound parabolic collector using ANSYS Fluent Computational Fluid Dynamics software and to integrate the same with an organic Rankine cycle engine to assess the thermodynamic performance of the system under very low mass flow rates (0.003–0.009 kg/s), different solar irradiances (300–1000 W/m²) and ambient temperature levels (24–40 °C). In the integrated mode, the organic fluid is passed through the collector, which re-enters the engine after heating. The influences of the rate of mass flow and ambient parameters on the working fluid outlet temperature, collector efficiency and collector heat loss are investigated parametrically for performance assessment of the collector. In the integrated mode, the effects of solar radiation, pressure ratio, working fluid outlet temperature and condenser side temperature on the maximum achievable thermal efficiency and work output are analysed using Engineering Equation Solver and compared with a standard engine. The results reveal that increasing the turbine inlet pressure, decreasing mass flow rate of flow and decreasing the cold side temperature of the turbine could improve system performance. The integrated unit is capable to show maximum efficiency of 13.03%, which is an increase by 3.7% compared with an earlier study of similar system having same working fluid.