Review on application and research of trans-critical CO2 refrigeration system in food freezing and cold storage

Abstract

As people pay more and more attention to environmental problems, the GWP and ODP of traditional halogenated hydrocarbon refrigerants are generally higher, and the natural refrigerants with low GWP are more mentioned. As a natural refrigerant, CO2 is excellent in safety and environmental protection. CO2 as a refrigerant also plays a role in various industries, especially in the food industry. In the actual use of CO2 trans-critical refrigeration system in food refrigeration, it is found that there are some defects in CO2 system. Therefore, in order to solve the problem of low efficiency in trans-critical CO2 cycle, this paper analyses the research of some technologies in trans-critical CO2 refrigeration system that can improve system performance, COP and refrigeration capacity, and summarizes the problems in recent years progress in energy efficiency. In this paper, the working principle, technical characteristics and the improvement of system performance of various improved technologies are discussed in detail, and the previous research is summarized.