| Summary: | 碩士 === 國立勤益技術學院 === 冷凍空調系 === 94 === The research design a two-phase type closed loop cooling system for high power desktop personal computer CPU of the future. This system comprised of a liquid miniature pump, a condenser is bought from commercial market, and a evaporator module designed by oneself. The system working fluid is dielectric liquid FC-72, which boiling temperature is lower than CPU operation temperature. The heater is 3.1× 3.1cm2 that simulation CPU. In the research, the effect of evaporate module geometry, evaporate module inlet and outlet position, coolant charge pressure, coolant flow rate and the environment temperature are studied, and compare the two-phase system performance with water cooling system. The experiment results are when increase the input power and environment temperature, the system thermal resistance of FC-72 will decrease, but that of water cooling system will maintain constant. The total thermal resistance of FC-72 cooling system can low to 0.19℃/W under 200 W input power and 40℃ environment temperature. The evaporator module thermal resistance will decreased when coolant charge pressure was decreased, because of coolant charge pressure has influence on saturation and subcool temperature, and the coolant flow rate has almost no influence on system thermal resistance for high input power. Furthermore, this research also test several mini-channel evaporator modules with different channel width in order to improve coolant and temperature distribution, the result show the temperature difference between highest and lowest evaporator modules wall is 2.6℃, So this method can improve the nonuniform problem of coolant distribution substantially. This research also test minichannels which two heat transfer area, pillar fin, impingement jet three different evaporate module flow path geometry, the result is maximum heat transfer area of minichannel evaporator module match the inlet position in the center, the thermal resistance value 0.117K/W is lowest when the 200W input power.
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