Designing a properly sized air conditioning system is an effective way to increase energy efficiency and minimize your electrical bill. Proper sizing also avoids a situation where IT equipment overheats and ceases to function. The total heat output of a system in a small IT space or wiring closet with little lighting and few, in any, people is the sum of the heat outputs of the IT equipment, UPS, power distribution, and air conditioning units. (Note: 1 watt of power consumed = 1 watt of heat that needs to be removed).
Heat output of UPS and power distribution systems consists of a fixed loss and a loss proportional to operating power. These losses are consistent across equipment brands and models, and so they can be approximated without significant error.
The information needed to determine the cooling load for the complete system can be gathered by measuring values such as the floor area in square feet, and the rated electrical system power.
3 easy steps for formulating a proper estimate
The following is a simple step-by-step guide for calculating room
or closet heat output.
- 1. Determine heat output in Watts (equal to Joules/second), which is becoming the worldwide standard unit of measurement.
- 2. Measure the following power / heat outputs (again in Watts):
a. IT equipment
b. UPS with battery
c. Power distribution
d. Lighting (if room /closet is kept lit most of the day and night)
- 3. Determine other sources of heat in the room:
a. Environmental heat such as sunlight through windows
b. Heat conducted in from outside walls; many small data centers and network rooms do not have walls or windows to the outside, so this impact may be minimal
c. If people are in the room, this contributes to the heat output
Your bottom line number will tell you what size of cooling unit you need.