A common misconception about heat load in an electrical enclosure is that the amount of heat is relative to the volume of air within the cabinet. While the volume of air is important, it is also dependent on the enclosure size as a whole, and a much more fitting approach is to consider the amount of heat transferring through the surface area (of the enclosure).
An end user recently reached out to me with an overheating enclosure (shown above), facing the problem which plagues all overheated electronic devices – downtime. And, in this particular case, the customer was concerned about the size of the enclosure, considering it to be rather large.
Truth be told, they were right! But, the size of the enclosure isn’t the only variable we consider when calculating heat load and recommending Cabinet Coolers. We also consider the temperature differential currently in place, and the maximum (worst) possible operating conditions (and subsequent ΔT under those conditions). We also consider whether any fans are currently in place, using their diameter to determine flow and calculate the heat each fan is removing from the enclosure. We then use this data to offset the heat load calculated based on surface area and temperature differential.
Using the Cabinet Cooler Sizing Guide to gather these details and determine heat load, we can definitively calculate BTU/hr., Watts, kcal/hr., or any other heat load variant. If you have an overheating enclosure and need a hand determining the best method to cool it, contact an EXAIR Application Engineer.
Lee Evans
Application Engineer