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Title: Comparative analysis of various CO2 configurations in supermarket refrigeration systems

Our paper presents an analysis of various CO2 transcritical and cascade/secondary loop refrigeration systems that are becoming popular in supermarket applications with the objective of optimizing the operating parameters of these systems. In addition, the performance of selected CO2-based refrigeration systems is compared to the baseline R404A multiplex direct expansion system using bin analyses in the eight climate zones of the United States. Moreover, for the refrigeration systems investigated, it was found that the Transcritical Booster System with Bypass Compressor (TBS-BC) had the lowest energy consumption for ambient temperatures (Tamb) less than 8 °C, and for higher ambient temperatures the R404A direct expansion system was found to have the lowest energy consumption. Finally, the TBS-BC performs equivalent to or better than the R404A direct expansion system in the northern two-thirds of the US. For the southern portion of the US, the R404A multiplex DX system performs better than CO2 systems.
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  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
International Journal of Refrigeration
Additional Journal Information:
Journal Volume: 46; Journal Issue: C; Journal ID: ISSN 0140-7007
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION Refrigeration; Transcritical booster system; Cascade system; Secondary loop system; Carbon dioxide; Thermodynamics