These chillers use CO2, a natural refrigerant, instead of chlorofluorocarbons, which have an impact on global warming and ozone layer depletion. The high-performance compressor and control system enable efficient operation, and the system has achieved energy savings of 20-40 compared to conventional R22 CFC refrigeration units. In addition, the air-cooled system uses zero water, eliminating water costs, and is also a powerful tool for BCP in the event of a disaster. The system can be used in a wide range of applications, including frozen and refrigerated warehouses, distribution centers, food factories, pharmaceutical companies, and chemical companies.