Numerical Simulation Research On The Cooling System Of CPU Based On Thermoelectric Cooling

With the rapid development of electronic technology, the cooling problems of CPU have become the bottleneck which is restricting its development. Thermoelectric cooling(TEC) with a compact, low noise, precise temperature control, etc., has great value in the CPU cooling. In this paper, research mainly focus on optimization of performance and the effective operating range of cooling system of CPU based on thermoelectric cooling. It can provide some theoretical support for thermoelectric cooling applied in CPU cooling.Firstly, it analyzes the heat transfer characteristics of thermoelectric module. The role of the Joule effect in the thermoelectric cooling process is studied, and a relatively accurate mathematical model of thermoelectric cooling is obtained. And then to optimize the entire cooling system of CPU based on thermoelectric cooling. The cooling system of CPU which the hot side of thermoelectric module using a heat sink and fan is established, and the heat transfer model of the system is established, the formulas for calculating the thermal resistance of each part of the system are given. In order to simplify arithmetic, by the analogy of heat and electricity, the equivalent circuit model of the system for the simulation in PSpice is established. In order to study the operating voltage of thermoelectric module and cooling load how to influence the cooling performance of TEC system, transient cooling performance of TEC system is analyzed. The cooling fan airflow, ambient temperature and the number of thermoelectric module in the system which affect the cooling performance of TEC system are analyzed under steady state conditions,.In order to analyze the working condition range which make the TEC system work effectively, when one or two thermoelectric module are used in the system, the range of cooling load which the junction temperature not exceed the critical temperature of CPU are analyzed respectively, and the TEC system is compared with using the heat sink and fan alone. Meanwhile, in order to prevent condensation in cold side, a theoretical method is proposed. Finally, the specific possible heat loads of CPU are simulated with finite element method, and the simulation results with previous findings are compared.The results show that the operating voltage, hot side resistance and ambient temperature have a significant effect on the performance of TEC system. The voltage which makes the thermoelectric module achieved a lowest cold side temperature will decrease with the increasing of the hot side thermal resistance. In this TEC system, when two thermoelectric modules are added, it can achieve the lowest minimum cooling temperature; while thermoelectric modules operating at the same voltage, using one thermoelectric module can achieve a maximum COP of the system. The TEC can't work well if the heat load of the CPU increase to a certain value, at this time, using the heat sink and fan of hot side will work better. However, when the heat load of CPU is appropriate, the cooling performance of TEC system is much better than the former.