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Description
The paper presents cooling system based on the Indirect Regenerative Evaporative Cooling concept. The developed prototype of the IREC system for electronics cooling is presented. Cooling relies on forced convection, where air is significantly cooled through evaporation. The system features two types of channels - dry and wet, through which the cooled air and moist air circulate. Water is supplied via porous membranes in the wet channels. The cooling system was tested in conditions of higher ambient temperature at the inlet.
Prototype of IREC system for electronic applications
Among different heat dissipation systems, the Indirect Regenerative Evaporative Cooling (IREC) becomes attractive as if can sustain effecting in the high ambient temperature. IREC is typically implemented by 2 thermally coupled air channels: dry (DC) and wet (WC) as shown in fig. 1a. Dry air passing DC is cooled down significantly due to the evaporation process in WC. The heat source is placed at the end of DC and beginning of WC, where the airflow cools down this source. This is the cooling area for an electronic device and the heating point for the dry air. Next, the heated dry air is directed to WC with wet walls made of the porous membranes sucking the water from the reservoir nearby. While air is flowing in WC, evaporation generates the cooling flux q as presented in fig 1a. Fig. 1b shows the wall of the dry channel during assembling the exchanger.
The mounted exchanger is presented in fig. 2 on the testing rig. This rig is equipped with numerous sensors in the different points for measure temperature, relative and specific humidity, pressure p and air velocity v. As seen in fig. 2b on the thermal image, the heat is generated by a power elements in the front side. There is a part of heat dissipated directly by natural convection to ambient. In order to reduce this leak of energy, the heat source was insulated by a box made of styrofoam.
Results
The measurement results are gathered in table 1. The measurement points 1…4 referring to ambient, DC outlet, WC inlet and WC outlet correspond to the numbers presented in fig. 1. In the experiment, the ambient temperature was increased above 40C by an external heater. The power P=12 W was dissipated in the electronic device generated the stabilized temperature T=45C using the PID controller.
