Research On Simulation Model Of Micro Channel Flat Loop Heat Pipe Based On Waste Heat Recovery In Data Center

Today's society is becoming more and more intelligent,information technology and IT industry is developing rapidly,the size of the data center is still expanding.However,the problem of high energy consumption and low energy utilization in data center is becoming more and more prominent,and the resulting energy crisis is becoming more and more serious.In data center,the most energy consumption component is the refrigerating system.The central air conditioning system in the traditional data center cannot take heat away effectively,and its hot and cold air mixing is easy to cause hot-spots.In contrast,the heat dissipation system which set close to the cabinet is more direct and can reduce the cabinet temperature effectively.But the exiting cabinet level or back plate type heat exchanger system need to transfer heat to heat pipe by fan,which cause a great amount of heat in data center.Not only bring unnecessary heat load but also caused more energy waste.Based on the structural characteristics of data center cabinet and IT equipment,this paper combined the micro-channel flat loop heat pipe with the IT equipment,and proposed a novel data center cooling and waste heat recovery system:Micro Channel Flat Loop Heat Pipe system based on waste heat recovery in Data Center.The novel system adopts micro-channel flat loop heat pipe to improve the temperature distribution in the cabinet,recovers the heat of the server directly from the source,and the evaporator of the micro-channel flat heat pipe fits directly to the surface of the IT equipment which can take away the heat load in a timely and effective manner.This study makes theoretical analysis and simulation model researches on the novel system,and finally gets an executable program for the user to design the novel system for data center heat recovery system.First of all,the current existence of the data center cooling system has carried out an extensive literature research,especially for the application of heat pipe in data center cooling system.The thermal characteristics of data center cabinets and IT equipment has analyzed and proposed the advantages and disadvantages of traditional data center cooling system.According to the micro-channel flat loop heat pipe structure,the author proposed a novel data center waste heat recovery system using micro-channel flat loop heat pipe.Secondly,theoretical analysis has researched for the micro-channel flat loop heat pipe using in data center waste heat recovery system.Through the knowledge of heat transfer,engineering thermodynamics,fluid mechanics and numerical analysis,the thermal transfer limit of the micro-channel flat loop heat pipe is simulated,and the maximum heat transfer of the micro-channel flat loop heat pipe is determined.The results show that there are six limits of the designed micro-channel flat loop heat pipe,namely capillary limit,sonic limit,entrainment limit,boiling limit,viscous limit,liquid filling mass limit.In the novel system studied and designed in this paper,the government limit is the capillary limit.In addition,based on energy conservation,quality conservation principle,the steady-state simulation model of system overall operation was established.According to the design parameters and structure of evaporator,the heat transfer simulation of condenser was researched,and the minimum length of the condenser and the recommended heat exchanger inlet water temperature were determined.Then the effect of filling ratio,water flow rate and heat load of IT equipment on the overall operating performance of the system is analyzed,the simulated operating efficiency of the system under each operating condition is obtained,and the relationship between the operating conditions and efficiency changes based on the micro-channel flat loop heat pipe is studied.The results show that the simulated heat recovery efficiency of the system can reach 86.67%at 35%of filling ratio,300 L/h of water flow rate,15?of inlet water temperature,0.8 m of evaporator-condenser height difference,and 500 W/m~2 of heat load of IT equipment.Through the experimental test data,the accuracy and reliability of the system simulation model are verified.The analysis results show that the optimal value of each operating condition and the heat transfer and its efficiency under the experimental conditions are basically in line with the simulation value,the error is less than 10%.The filling ratio is35%,the water flow rate is 300 L/h,the inlet water temperature is 15?,the evaporator-condenser height difference is 0.8 m,the heat load IT equipment is 500 W/m~2,the experimental test heat recovery efficiency can reach 84.52%,simulation and experimental error is only 2.54%.Finally,according to the above research basis,the simulation program of the proposed data center waste heat recovery micro-channel loop heat pipe system is further optimized and interface is designed,making it easy for engineers to apply.The interactive visual interface as the user side will provide feasible parameter reference for the design of the data center micro-channel flat loop heat pipe waste heat recovery system.