Optimum Sized Air Channels for Natural Convection Cooling

Natural convection cooling is widely used for temperature control in electronic equipment. The amount of heat that can be removed is determined by three factors: the temperature difference, the cooling area and the heat transfer coefficient. Heat transfer calculations for idealized cases are relatively easy and the results of these often give a good lead for the mechanical design of electronic equipment. As it is a general desire to keep the volume of an equipment at a minimum, one of the most important aims is to maximize the heat dissipation in a volume for a given temperature difference. The optimum spacing for PCB:s in cabinets cooled by natural convection will depend on the pattern of air flow through the cabinet. The air flow pattern is also very important for the possibilities to improve heat dissipation with component coolers. The optimum fin spacing for component coolers used with natural convection will vary with many factors but is generally between 5-15 mm.