Experimental Study Of Water Storage Unit Combined With Data Center Cooling System

Domestic demand for electricity power is increasing presently with the growing economy in China,companying with the prospering development of big data and“Internet+”industry,which significantly boosts the construction of computing data centers on a large scale quantitively,and thus induces extra cost for distribution of electricity power as well as the operation of refrigeration system.The current status draws much attention from researchers,and they have been working together for promising solutions,among which the cooling storage technology,effectiveness on regulating the extremum and shifting the load of electricity,presents the feasibility on utilization of low-cost electricity from the national grid at night for handling the heat load of air conditioning systems during the day.This might relief the intensity of electricity power in the gird,and also reduce the operation cost of the system further,demonstrating its economic effects.In regard of this,experimental study of a three-stage water storage unit based on micro-channel flat heat pipes is conducted in this thesis.Relevant concerns might be concluded as follow:Firstly,design of the existing heat pipe cold storage unit has been optimized for improvement,and then working principle of the three-stage water storage unit based on microchannel flat heat pipe would be carried on,after which materials of the cold storage unit,refrigerant adopted,design and fabrication of the device,construction of the experimental setup,choses of experimental conditions and the final testing scheme would be introduced.Secondly,the experimental setup would be tested for cold storage performance and cold release performance respectively by varying the working fluid,charge rate,inlet temperature and flow rate of the refrigerants.Indicators such as the cold storage capacity,cold storage efficiency and cold storage energy density are conducted to study their effects on the cold storage performance.Likewise,indicators such as the cold release coefficient are calculated to investigate their influence on the cold release performance.The result shows that the optimum storage conditions,20%filling rate of the acetone,as the working fluid,with 2°C carrier inlet temperature and 600L/h carrier flow rate,which resulted in a storage capacity of3.048MJ,a storage efficiency of 69.73%and a storage energy density of 40.43J·K^-1·kg^-2.The optimum cooling release condition is 77.64%at the refrigerant flow rate of 600L/h with the same conditions.To compare the cooling storage system with the conventional one,parameters from certain data centers in Shanghai and Guangzhou were adopted.Then,economic effects and environmental benefits of the cooling storage system were assessed by analyzing the time-sharing tariff policy,initial investment of the system,payback period,and the energy saving and emission reduction performance.The result shows that the static payback period of the system is 3.42 years and 3.45 years respectively,both less than 5 years,with considerable economic benefits;the total energy saving,and emission reduction benefits are$1753.05 and$4554.03 correspondingly,which is relatively significant.