Next-generation refrigerants and energy efficiency in walk-in coolers and freezers in the U.S.

Abstract

Commercial refrigeration systems, particularly walk-in coolers and freezers, are essential for preserving perishable goods across various industries, including food storage and supermarkets. This paper presents a comprehensive review of advancements in walk-in coolers and freezers, focusing on three key areas: the transition to next-generation refrigerants, regulatory developments, and technological innovations aimed at improving energy efficiency. Our review reveals that CO2 systems, particularly in transcritical booster configurations, are effective solutions for large parallel rack walk-in coolers and freezers due to their efficiency. For smaller remote walk-in coolers and freezers, R454A, R454C, and R455A stand out as efficient options. Similarly, R454C and R455A prove to be efficient choices for smaller self-contained walk-in coolers and freezers. Additionally, this paper explores technical challenges associated with zeotropic blends, such as glide and fractionation, and their implications on system performance and design.