Heat Dissipation in Electrical Enclosures

Selection Procedure:

1. Determine input power in watts per square feet by dividing the
   heat dissipated in the enclosure (in watts) by the enclosure
   surface area (in square feet).
2. Locate on the graph the appropriate input power on the
   horizontal axis and draw a line vertically until it intersects the
   temperature rise curve.
3. Read horizontally to determine the enclosure temperature rise

Example:

What is the temperature rise that can be
expected from a 48″ x 36″ x 16″ enclosure with 300 watts of heat
dissipated within it?

Solution:

Surface Area = 2[(48×36) + (48×16) + (36×16)] divided by 144 =
42 square feet

Input Power = 300/42 = 7.1 Watts/SqFt.

From Curve: Temp. Rise = 30°F (16.7°C)