Parametric study of a Novel Hybrid Solar Variable Geometry Ejector cooling with Organic Rankine Cycles

The effect of ejector area variation to account for the unsteadiness of the driving low-grade solar energy source on the cycle performance of a combined variable geometry solar ejector cooling Organic Rankine Cycle under different operating conditions was studied. An Organic Rankine Cycle was combined with the ejector cooling cycle to utilize the excess solar heat in peak hours and to generate power. Simulation and modeling of the system were conducted using the Engineering Equation Solver and Ebsilon Software. Conservation principles and laws of mass and energy transfer were applied to all components of the system and a one-dimensional thermodynamic model was used to model the ejector. It was found that the effect of the ejector area ratio and evaporator pressure were more predominate on the cycle performance than that of the generator pressure. An improvement of 78% of the system coefficient of performance compared to the standard ejector cooling cycle could be achieved using the Variable Geometry Ejector. In addition, further enhancement in the system coefficient of performance could be achieved by regulating the generator and evaporator pressures. The Organic Rankine Cycle efficiency was found to be 5.8% with a total system efficiency of 11.35%. The system cooling capacity was improved by 81% compared to the standard ejector cooling cycle. The proposed system was found economically feasible in countries, where the electricity price is higher than 15 c$/kWh.