New Developments on Carbon Dioxide Refrigeration Technologies

As CFCs deplete ozone, natural refrigerants such as carbon dioxide have attracted more and moreattentions. In this paper, the history of carbon dioxide as a refrigerant is introduced, and the reasons that it was givenup as a refrigerant is explained. According to the thermophysical and chemical properties of carbon dioxide and thethree possible carbon dioxide refrigeration cycles, the advantages and necessarily of carbon dioxide transcriticalrefrigeration cycle are formulated. The researches and developments of carbon dioxide refrigeration, air conditioningand heat pump system and its applications are reviewed and predicted.