Research On Integrated Refrigeration Air-condition System Based On Free Cooling Of Data Center

Data center is called modern black hole.The energy consumption of the air-condition system used for data center environmental control accounts for 35~45%of the total energy consumption of the data center.Developing the efficient cooling system is an important approach for energy-saving of data center.Free cooling is an effective energy saving scheme for data center air-conditioner.Free cooling can be divided into air-side free cooling,water-side free cooling and heat pipe free cooling,and heat pipe free cooling gains focus attention for its efficient heat transfer characteristic etc.Based on the previous research,a system integrating free cooling and vapor compression refrigeration was developed,and performance testing and engineering application have been completed.The main work and innovation results are as follows:1)HFK-200FH of the integrated unit with free cooling and vapor compression refrigeration was developed.The unit is composed by a vapor compression refrigeration system and a separated heat pipe system,which separately apply the first coolant and the second coolant that is driven by a liquid pump.It has three operation modes:the compression refrigeration mode,the dual refrigeration mode and the free cooling mode.The whole cooling capacity is provided by the vapor compression refrigeration unit in cold seasons.Besides,the cooling capacity is fully provided by the heat pipe unit in hot seasons.In transition seasons,the vapor compression refrigeration is the auxiliary of the heat pipe unit.2)The outdoor heat exchanger used for integrated refrigeration unit was designed in a composited heat exchanger structure,which is composed by the heat pipe unit air-cold heat exchanger,the vapor compression refrigeration unit condenser and the sharing fan.The air-cold heat exchanger is set in the air inlet-side and the condenser is set in the air outlet-side.3)The key coupling component tube and shell evaporative condenser was designed.The tube pass,as the compression refrigeration evaporator,provides the second coolant with the cooling capacity when operating the refrigerating mode and the dual refrigeration mode.4)The performance test scheme of HKF-200FH was designed(the secondary fluid calorimeter method).The performance test showed that the cooling capacity/EER were 197.38 kW/3.5 and 196.89 kW/15.3 in the conditions when the vapor compression refrigeration unit works(ambient temperature:35 ~oC)and when heat pipe unit works(ambient temperature:10 ~oC)respectively.The integrated refrigeration unit can flexibly switch operation mode according to the outdoor working condition.5)Engineering application situation of the integrated refrigeration units was analyzed.Two sets of HKF-200FH are applied in an air-conditioner engineering of an EB level Cloud storage Laboratory in Beijing,and the operation results showed that the annual energy-saving rate is about 45%compared with the traditional CRAC.The advantages of it in safety,reliability and energy-saving are obvious.The integrated system with free cooling and vapor compression refrigeration,based on the separation heat pipe,widens the temperature range of free cooling,and realizes the efficient utilization of natural cold source.So it is specially applied in all-weather running data center for the environment control of electronic and electric equipment etc.