An Experimental Investigation of Free Convection Cooling of Electronic Equipment (2nd Report)

In the present experiment, the following two types of the cabinet were used to study free convection cooling of electronic conponents on a PWB (Printed-wiring-board, with fins or without fins). Case 1. Small holes for ventilation were made in the front-side panel and the bottom panels of the cabinet. Case 2. Small holes for ventilation were made in the top panel and the bottom panel of the cabinet. It seemed that the space between the PWB and the side panels of the cabinet (corresponding to ventilating area ratio of 12% in the present experiment) was an important factor for ventilation cooling. The hottest temperature on the PWB inside the Case 1 cabinet was lower than inside the Case 2 cabinet with the same ventilating area ratio. In the Case 2 cabinet, a local spot on the PWB could be cooled intensively by the fresh air from the hole in the bottom panel.