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Stefan Elbel, Ph.D., Creative Thermal Solutions and University of Illinois at Urbana-Champaign |
The low GWP of natural refrigerants makes them great candidates for commercial refrigeration. An important characteristic of transcritical CO2 cycles are the substantial throttling losses that negatively impact energy efficiency at high ambient temperatures. This presentation introduces numerous ways of improving COP at demanding outdoor conditions, and the emphasis will be on utilizing two-phase ejectors. A variety of cycle options exist that allow integration of ejectors, including utilization of the recovered energy to unload the compressor, to provide cooling at different temperature levels and to improve efficiency by using the ejector to drive refrigerant overfeed in liquid recirculation cycles.