This work presents the thermal design of a novel evaporator geometry of a miniature refrigeration system to assist the existing heat pipe technology currently used for chip cooling of portable computers. A coupled heat transfer model for the evaporator/heat pipe assembly was devised specifically for the purpose of sizing the evaporator in order to keep the temperature of the chip surface below a certain design value. Next, an evaporator prototype was fabricated and evaluated in an experimental facility in which the temperature and the pressure at the evaporator inlet and the refrigerant mass flow rate can be specified. Refrigerant 600a was used in all experiments. Saturation temperatures of 45 and 55 deg C, mass flow rates between 0.5 and 1.5 kg/h have been evaluated for heat transfer capacities ranging from 30 to 60 W. The experimental results demonstrated that forced convective boiling was the main heat transfer mechanism in the evaporator mini-channels. The agreement between the refrigerant heat transfer coefficient calculated by the model and the experimental data was within +-5percent for the conditions evaluated.
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