Transcritical R744 refrigeration systems for supermarket applications: Current status and future perspectives

Visible signs of climate change call for urgent actions on food retail industry, since such a sector is characterized by an abundant carbon footprint. Being CO2 (or R744) recognised across the world as the most promising working fluid for supermarket applications, commercial transcritical R744 refrigeration systems have emerged as leading hydrofluorocarbon (HFC)-free technologies. This study is intended to implement an in-depth review study covering the most important aspects related to the state-of-the-art pure R744 refrigeration plants for food retail applications, including the evolution of system architectures, some field measurements, the main available results from an energy, environmental and economic perspective as well as the indispensable future investigations. It could be concluded that, in spite of some persisting barriers which still prevent such technologies from a wider adoption, the usage of R744 as the only refrigerant in supermarkets is no longer open to dispute, even in warm locations.