Energy Saving Analysis Of Air Cooled Data Center With Heat Recovery Device

The growth of data centers has accelerated due to the quick advancement of information technology and the rising demand for data processing and storage.Its energy consumption accounts for 3.3%of social electricity consumption,and the percentage of data centers’energy use has been rising.A sensible use of this portion of energy consumption can effectively lower the total energy consumption of data centers and reduce some carbon emissions.The refrigeration system accounts for 31%of the total energy consumed by data centers,and the refrigeration process is accompanied by a significant amount of waste heat generation.The majority of currently operating data centers use air cooling,and the heat return air in air-cooled data centers has a certain potential of waste heat.This paper takes an air-cooled data center in Shanghai as the research object,uses TRNSYS energy consumption simulation software to establish the simulation platform of data center refrigeration system with waste heat recovery device and the original data center refrigeration system without waste heat recovery in Harbin,Changchun,Taiyuan,Shanghai and Haikou,and analyzes its energy consumption.Then,through further design and optimization of data center operating parameters,the optimal working conditions are obtained.Finally,the performance of the five cities under the most used conditions is evaluated.First of all,by determining the cooling technology of the data center and the residual heat under the corresponding conditions,it is determined that the hot return air temperature of the data center can reach 30-40℃,which has the feasibility of utilization.By analyzing the basic situation of the data center and analyzing the load situation of the data center,the air-cooled chiller,cooling coil,water pump,chilled water supply and return water pipe and waste heat recovery module used in TRNSYS are determined,and a detailed introduction to the mathematical model and simulation model’s parameter setting and operation control method.The modeling environment of two kinds of refrigeration system with or without waste heat recovery device was built.Secondly,the energy consumption analysis of the five cities under the initial conditions shows that the addition of the overall energy required for data center cooling can be decreased with waste heat recovery devices,and the effect on different cities is different.The energy-saving effect is in descending order:Harbin>Changchun>Taiyuan>Shanghai>Haikou.The energy saving rate also reached 62.2 percent,59.7 percent,51.3 percent,36.9 percent and 18.8 percent respectively.In addition,optimization of various refrigeration parameters.It was determined that the total energy consumption of refrigeration system reached the lowest when the air supply temperature reached 22℃in Harbin and Changchun,and 26℃in Taiyuan,Shanghai and Haikou.In areas with high outdoor temperature,the total system energy consumption changes more obviously by changing the temperature of chilled water supply.In Taiyuan,the total system energy consumption decreases by 0.165%when the temperature of chilled water supply increases by 3℃;in Haikou,While the chilled water rises by 3℃,the overall system energy consumption falls by 2.9%.The overall amount of energy used by the refrigeration system with waste heat recovery is not significantly affected by the expanding of the temperature.Under the air supply condition of 26℃,the optimal natural cooling switching temperature of Harbin and Changchun is t₁=-20℃,t₂=-10℃,Taiyuan is t₁=-15℃,t₂=-5℃,Shanghai is t₁=-4℃,t₂=6℃,Haikou is t₁=8℃,t₂=18℃.Finally,the performance of the optimal waste heat recovery conditions in different regions was evaluated,and it was concluded that Harbin and Changchun could achieve lower PUE compared with other regions.The energy utilization efficiency and waste heat recovery were related to the urban climate,in the order of Harbin>Changchun>Taiyuan>Shanghai>Haikou.In addition,due to the different carbon emission factors in different regions,the reduction of carbon emission is presented as Taiyuan<Haikou<Changchun<Harbin<Shanghai.In conclusion,Harbin and Changchun are more suitable to build data centers with waste heat recovery devices than other regions.For energy saving retrofitting,it has more potential due to its lower PUE and higher energy saving rate than the original data.Shanghai has more potential to reduce carbon emissions.