Experimental and computational studies on a steam jet refrigeration system with constant area and variable area ejectors

• Experimental and computational studies on steam jet refrigeration system carried out.
• Constant area and variable area ejectors were designed for low heat input.
• Evaporator temperature was varied from 5 °C to 15 °C and the boiler temperature from 90 °C to 120 °C.
• At the lower boiler temperature, no shock formed in the variable area ejector resulting in better performance.
• A steam jet refrigeration system can operate steadily at boiler temperature of 90 °C.

This paper first presents the results from an experimental study of a conventional steam jet ejector refrigeration system and compares the performance with the computational fluid dynamics (CFD) results of the same. Secondly, it describes a method of developing a variable area supersonic ejector and presents experimental results of the operating performance of the variable area ejector over the same operating conditions. The two ejectors were experimentally tested for boiler temperatures below 120 °C and an evaporator temperature below 15 °C. It was found that the steam jet refrigeration system can operate with stability at low boiler temperatures of around 90 °C and supersonic ejector can enhance the performance of the refrigeration system by eliminating the shock from the ejector.

The work aimed at studying the performance of a steam jet refrigeration system with (i) a constant area ejector and (ii) a variable area ejector under different operating conditions both experimentally and computationally. The boiler temperature was varied from 90 °C to 120 °C, the evaporator temperature was varied from 5 °C to 15 °C and the entertainment ratio, variation of Mach number along the ejector and the Coefficient of Performance were obtained. With proper design, the shock phenomenon in the variable area ejector was eliminated as shown in the left figure, which resulted in a better performance of the variable area ejector over a range of evaporator temperatures. The study also confirmed that the system can operate steadily at a boiler temperature of 90 °C which can be obtained from waste heat.Figure optionsDownload as PowerPoint slide