Investigation on the thermal resistance and response time of passive cooling system

An experimental study of thermal resistance and response time of a separate-type passive phase change cooling system was conducted in this paper. Thermal resistance and response time of the cooling system were the characteristics of steady and transient states, respectively. Based on the established heat transfer model in the heat transport pipeline, the study focused primarily on the effects of inner diameter, tube length, and inclination angle on these two parameters. Experimental study showed that the cooling system had a good performance when the supplied heat loads increased suddenly. Thermal resistance decreased with decreasing inner diameter, tube length and inclination angle, while decreasing as the heat loads increased. When the thermal resistance became lower, it was indicated that the heat transfer during in-tube condensation in the heat transport pipeline was low and the temperature field along the pipeline was uniform, thereby the corresponding response time was shorter.