Experimental And Application Study Of Micro-channel Backplate Heat Pipe System

The electricity consumption of data centers has been rapidly increasing with the development of the Internet.While more than 45% of the electricity consumption is used for air conditioning,and the heat density of single rack has been rising quickly at the same time.Using traditional computer room air conditioner(CRAC)for data center cooling exists several problems such as bad air distribution and local overheating.Compared with the CRAC system,the microchannel backplane heat pipe system(MCBHP)has the advantages of higher heat transfer performance,lower refrigerant pressure drop,saving space,close to heat resource,which can realize cooling on demand and reducing energy consumption.Firstly,the thermal performance of the MCBHP tests were carried out in an enthalpy difference laboratory.As a result of experiments,the optimal filling ratio(FR)of the MCBHP is 65%~75% with different conditions and the maximum heat transfer rate is 7 ~ 8kW.At the optimal filling ratio,the MCBHP obtained the maximum heat transfer rate and low temperature difference between the inlet and outlet of the evaporator section and the condenser section,while the refrigerant is at the two phase flow state.Secondly,a steady state mathematical model is developed according to the energy(enthalpy),momentum(pressure),and mass conservation and validated with experiment data in this paper.The average relative error of the simulation and experiment is about 10%.Through the simulation of the model,the outlet temperature of the evaporator is evenly distributed in vertical.The influence of structure parameters of heat exchanger on the heat transfer performance of the MBCHP were analyzed,the sensitivity analysis of the MBCHP cooling capacity to the operational parameters were carried out,which can provide reference to optimize structural and operating design of the MBCHP.Finally,a simplified heat transfer prediction model was developed,which can satisfie the requirements in practical projection with relative error in 10%~12%.on the basis of simplified heat transfer prediction model,an energy consumption simulation model was designed of a typical data center according to the chiller,the pump,the terminal units and the indoor thermal environment.Compared with the conventional CRAC system,the energy saving rate of the cooling plant for the data center with MBCHP system is 14.33%.