PARAMETRIC ANALYSIS OF AN EJECTOR REFRIGERATION CYCLE ACTIVATED BY RENEWABLE ENERGY

The refrigeration and cooling systems activated by waste heat and renewable energy sources can achieve high energy efficiency. In this paper, a performance investigation and working fluid choice for an ejector refrigeration cycle (ERC) activated by renewable energy source are conducted. In the ejector mathematical model, the mixing process through the ejector constant-area section is supposed to be constant-pressure process. The performance of some selected hydrocarbons, hydrofluoroolefins, hydrofluoroethers, and hydrofluorocarbons refrigerants in the ERC is examined and compared. The behaviour of the ejector is represented by the ejector area ratio (EAR) and entrainment ratio (), whereas the cycle performance is represented by the coefficient of performance (COP). The impacts of some selected operating parameters as the condenser, evaporator, and generator temperatures on the ejector behaviour and cycle performances are also examined. The results show that the best ejector behaviour and cycle performance are achieved with the highest critical temperature dry refrigerant, i.e. cyclopentane under all examined operating conditions. From energy efficiency and environmental issues viewpoints, cyclopentane can be considered the most appropriate refrigerant amongst all examined working fluids. However, additional precautions should be taken against its flammability. The highest COP value, the corresponding ω, and the needed EAR using cyclopentane are 0.81, 1.03, and 17.3, respectively with a condenser temperature of 25 ºC and the typical values for the remaining operating parameters.