Abstract: Based on the basic theory, a phase change refrigeration cycle system from cabinet to outdoor environment is constructed, which uses gas pump, liquid pump, evaporation condensation, gravity heat pipe technology and so on. This system can transport the heat from the server to the outdoor environment efficiently and there is no intermediate heat exchange in the whole process. Therefore, this system can minimize the difference between evaporation temperature and condensation temperature. The test results show that the cooling system annual average energy efficiency ratio can be above 20 when it is used in the national core city data center. At the same time, the system also has the advantages of high peak energy efficiency, applicability and compatibility, which further reduces the construction and operation costs of the data center.

Key words: data center, phase change cooling, natural cooling, energy efficiency