The ejector, which is the heart of the jet refrigeration system, was invented in 1901 for removing air from a steam engine’s condenser. In 1910, an ejector was used in the first steamjet refrigeration system. Finally, in 1913,an ejector was used in air conditioning large buildings. Steam jet refrigeration systems were later supplanted by systems using mechanical compressors. Since that time, development and refinement of jet refrigeration system have been almost at a standstill as most efforts have been concentrated on improving vapour compression refrigeration systems. A schematic view of a typical steam ejector is shown in Fig. 1. The flow process is also presented in Mollier’s chart Fig. 2. Referring to Fig. 1, as the high pressure steam(P), known as ‘primary fluid’, expands and accelerates through the primary nozzle (i), it fans out with supersonic speed to create a very low pressure region at the nozzle exit plane (ii) and hence in the mixing chamber. According to the differences of pressure of two positions, higher-pressure vapour,