Investigation of experimental performance of combined Rankine and vapor compression cycles using an ejector

In this paper, the theoretical and experimental performance of the ejector refrigeration cycle is investigated. Making use of EES software, laws of mass and energy conservation as well as the exergy balance equations, a one-dimensional thermodynamic model is developed and validated using experimental results obtained in the laboratory. It is assumed that mixing takes place at a constant pressure and a constant cross section part of the ejector. Two factors are considered as the most important effects in the modeling: the frictional loss due to the mixture of the flows and the efficiency at the different parts of the ejector. Also a parametric study is carried out to study the effects of evaporator and generator temperatures on the coefficient of performance and second law efficiency of the cycle. The results indicate an increase of COP with increasing evaporator temperature. The maximum exergy losses occur in the ejector, generator and condenser respectively. Also at any pressure in the generator, an optimum value exists for the second law efficiency. Also the exergy destruction distribution analysis indicate that the highest exergy destruction occur in the ejector, condenser and generator.