Volume 8 Issue 1 ( March 2021 )


Thermodynamic Feasibility Evaluation of a Novel Low-temperature Ejector- based Trans-critical R744 Refrigeration Cycle

Mojtaba Purjam, Kyaw Thu, Takahiko Miyazaki


In conventional ejector refrigeration cycles, the ejector mostly operates at fixed pressure points in the secondary stream and outlet. Studying the sensitivity of the system to the pressure alternation of the mentioned points has not been investigated. To cover this gap, an extra turboexpander, compressor, and gas cooler were introduced to the conventional ejector layout. It was found that pressurizing the secondary entrance of the ejector could be beneficial to COP if it is not warmer than the gas coolers. Also using the expansion process right after the ejector has the potential to increase the efficiency of the system if the discharge pressure of the ejector reaches supercritical or superheat condition.

Keywords: Ejector; Trans-critical CO2; Low-Temperature Refrigeration; Turboexpander