Design And Economic Operation Of Indirect Liquid Cooling System For Data Center Server

In recent years,the number of data centers has grown rapidly,and the associated energy consumption problem has become more and more serious,of which the cooling system energy consumption accounts for more than one third.Traditional air-cooled due to problems such as air flow organization and management is difficult to meet the cooling requirement of high heat flux chips,high new liquid-cooled technology in improving the heating element thermal environmental performance is outstanding,but due to objective reasons such as design,coolant flow rate of supply and demand cause surface cooling system power consumption is high,therefore,to carry out the research of energy saving of the engine cooling system is of great significance.In this paper,the indirect liquid cooling heat dissipation model of the cabinet is established,and four kinds of cold plate structures are proposed.Through numerical simulation,the central diffusion structure has excellent performance in heat dissipation performance and temperature homogeneity.Based on the pipe network model,the structural parameters of the pipe network were set,the hydraulic smooth zone formula was analyzed and selected to calculate the drag coefficients along the main section,manifold section and branch section,and the local drag calculation formula of the parts with sudden expansion and contraction was deduced.The local drag of the parts with elbow,tee and valve was calculated by using the empirical formula.The resistance distribution characteristics of the pipe network system are analyzed,the resistance model of the liquid cooling cooling system is built based on the resistance coefficient of the pipe network,and the software of pipe network system design and resistance solving is developed by using the MatlabAppDesigner module,which has important reference value for engineering application.In order to optimize the liquid cooling system of the cabinet,the overall physical model of the liquid cooling system of the server cabinet in the data center was established.The flow and heat transfer characteristics of the system are analyzed on the basis of the physical model of the system,and the overall flow and heat transfer constraints of the system are established based on the heat flow method and the hydrodynamic resistance equilibrium relationship of the pipe network.On this basis,the optimization analysis is carried out for the cabinet liquid cooling system under the centralized and distributed pump arrangement modes.For the heat dissipation system with centralized pump arrangement,the Lagrange function is established to minimize the system power consumption under a given thermal load,and the optimal operating frequency of the pump is obtained by combining with the variational principle.When the temperature of cooling water rises from 20℃ to 24℃,the total power consumption increases by 1.55 times.By comparing the influence of branch temperature and thermal load changes on the system and other branches,it is found that the influence of branch temperature changes on the system must be considered at the same time as the temperature of other branches,and the increase of branch thermal load will definitely lead to the increase of cooling water demand and power consumption.When the total load of the system is constant,servers with a specific load of 1.2KW are placed at the top and bottom of the cabinet respectively.The optimization results show that energy consumption can be saved by 34.4%if the server is placed at the bottom.Given the total pump power consumption of the system,the maximum heat load of the system is taken as the objective,the Lagrange function is established by combining the overall heat transfer and flow constraints of the system,and the optimal operating frequency of the pump is obtained by combining the variational principle.Under the given pump power consumption condition,when the inlet temperature of cooling water increases by 2℃,the total thermal load of the cabinet decreases by 4.9%.Based on the changing trend of heat dissipation of each branch with the increase of cooling power consumption of a given system,the nearby arrangement of high-load servers is more energy saving.For the liquid cooling system with distributed pump arrangement,the optimal operating frequency of the pump was obtained by combining the Lagrange function with the system constraint and the variational principle,aiming at minimizing the system power consumption under a given heat load.Through comparison,it is found that when the total heat load of the system increases from 4.0KW to 6.0KW,the distributed pump arrangement saves an average of 2.5 W,and the maximum energy can reach 7.09W,compared with the centralized arrangement.Through MATLAB platform developing data center server liquid-cooled cooling system optimization software module,the module first server layer and resistance design of pipeline system,then input the physical parameters of server heat load and cooling water,the last output each layer server minimum pump frequency and system power consumption value,liquid-cooled system operation parameters optimization design was realized.On this basis,the optimized software module was packaged and installed by packaging APP and creating independent desktop application,and the test results were consistent with the above research.Through the construction of optimization software module,the modeling and optimization efficiency is greatly improved,and a new research idea is provided for the future engineering practical application.