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[(48x36) + (48x16) + (36x16)] divided by 144 = 42 square feet

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

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