Test of condensing units performance and operating limits using different refrigerants

摘要

The European regulation has set a series of limitation to reach the objective of reducing the GlobalWarming Potential (GWP) emissions. Among these limits, the ban of Hydrofluorocarbons (HFC) refrigerantshaving a GWP higher than 2500 starting 2020. Replacement refrigerants, are, among others, the HFO blendsand the transcritical refrigeration system using CO2.In this paper, we present the outcome of a testing campaign aiming to compare the performance,operating range of a condensing unit of a rated capacity of 8kW operated with HFC 404A and three drop-inlow GWP HFO/HFC blends, and a second condensing unit of equivalent capacity using transcritical CO2.The comparison is made using different ambient temperatures while operating at the averageevaporating temperature. In addition, a numerical model simulated the efficiency increase of adding variouselements to the transcritical refrigeration system.HFO/HFC blends were found more efficient and capable of operating at a wide temperature range.