Thermal Management Best Practices

BY: Christina Hansen


By: Middle Atlantic Products

How to Calculate Ventilation Required to Provide an Interior Rack Temperature of 85°F

This nomograph will show the minimum ventilation (Active or Passive) required, to provide an interior rack temperature of 85°F.

To calculate total waste heat (column B):

  1. Obtain total waste heat output by combining the published waste heat BTU/Hr. of all amplifiers in the rack.
  2. Add up total measured amperage draw from all other equipment and multiply by 400 (total amperage x 400 = total BTU/Hr. @117v.)
  3. Combine BTU/Hr. totals from steps 1 and 2 to obtain total for all equipment. Mark total in column B.

To obtain minimum ventilation requirements:

  1. Mark ambient room temperature in column C and connect points in B and C with a straight edge.
  2. The minimum cooling required providing an interior rack temperature of 85°F will be shown on column A, where the straight edge intersects the minimum ventilation required column.

Nomograph showing range of temperature, BTU and ventilation


chart showing ventilation of home theaterIn addition to the proper configuration of the rack system, room design is critically important to the success of rack and enclosure thermal management. It is essential that not only does the equipment room have the ability to remove the heat generated by the racks, but also that racks are placed strategically within the room to ensure no-recirculation of air occurs.
The best start for thermal management is during the planning stages of new construction, by coordinating with architectural plans, building contractors HVAC plans and millwork specialists. However, regardless of whether planning is for a new or retrofit installation, there are several effective methods for thermal management that depend greatly on where the residential electronics system is being installed.

Consideration to a rack’s internal airflow is equally important to ensure effective thermal management. Simulations and real-world testing show that moving air through a cabinet from bottom to top results in the lowest internal cabinet temperatures for equipment with front intakes.


Best Enclosure Airflow Method

options for ventilation