Ejector design and theoretical study of R134a ejector refrigeration cycle

In the present paper, a mathematical model is developed to design R134a ejector and to predict the performance characteristics of a vapor jet refrigeration system over a wide range of the investigated parameters. These parameters include boiling temperature (65-85 degrees C), condensing temperature (25-40 degrees C), evaporating temperature (0-10 degrees C), degrees of superheat (0-15 degrees C), nozzle efficiency (0.75-0.95) and diffuser efficiency (0.75-0.95). Simulated results showed that the present model data are in good agreement with experimental data in the literature with an average error of 6%. It is found that the ejector area ratio at boiling temperature of 85 degrees C is about double that at boiling temperature of 65 degrees C for various evaporating and condensing temperatures. The present results confirm that waste heat sources of temperature ranging from 65 to 85 degrees C are adequate to operate vapor jet refrigeration system for air-conditioning applications. (C) 2011 Elsevier Ltd and IIR. All rights reserved.