Heat Release Calculations Per GR-63-CORE

To calculate Heat Dissipation or Heat Release for a shelf-level product:

Need to know:

  1. Height of the unit

    1. Includes the height of any required air ramps or spacers.

  2. Width of the frame

    1. For a 23-inch mounting, use a width of 26 inches.

    2. NOTE: Equipment mounts on 23 inch, but total width equals 26 inches.  The calculator shows a width of 23 inches, but will use 26 inches in the calculation.

  3. Depth of the frame

    1. Depth of the frame (Front and Rear aisle dimensions are from GR-63-CORE):

      i. 12 inch

      1. FrontAisle = 30 inches

      2. RearAisle = 24 inches

      ii. 18 inch

      1. FrontAisle = 54 inches

      2. RearAisle = 30 inches

      iii. 24 inch

      1. FrontAisle = 42 inches

      2. RearAisle = 30 inches

  4. Equipment power in Watts

    1. Multiply operating voltage (-48 Vdc) by maximum load current (A).

Example Calculation

Forced-air fans used to cool unit

Height of unit = 24.5 inches (2.042 ft)

Width of Frame = 26 inches (2.167 ft)

Depth of Frame = 12 inches (1 ft)

FrontAisle = 30 inches (2.5 ft)

RearAisle = 24 inches (2 ft)

Equipment power in watts = 457 Watts

31.8 W/ft2/ft is greater than 27.9 W/ft2/ft therefore this unit does not meet the GR-63-CORE Heat Release Objective.