I'm an IT system administrator and responsible for a 10' x 6' computer room. There is a two ton AC that cools this room and an exhaust unit in the ceiling
of the computer room; there are no windows, and we're on the 14th floor. Right now, things are cool in the room, however, we'll be adding equipment to
already existing equipment so I was wondering what the best way to go about calculating the power and cooling requirements would be. I have one telco rack
and one server rack, each has its own UPS that's rated at 1980 Watts/
2200 VA. No one ever really sits in the room, I go in there from time to time (swap outtapes, check out patch panel, etc.).
For the power, at first I simply added up all the maximum Wattage specifications for each piece of equipment, I know this figure is highly inflated since the
equipment does not run at full capacity all of the time. After doing some research, I thought it may be better to use VA (to account for the power factor)
instead of Watts, so I ordered a Kill-a-Watt tool to measure the power in VA (still waiting for it to arrive). As it stands, the telco UPS shows its load to
be at least 17%, the server rack UPS is much higher, at least 67%. I'm trying to keep the loads on the UPS's to under 75%.
I also had the building electrician drop by a while back and explain to me how the electrical outlets are arranged so that I can load balance the circuits
that are in the computer room. From what I was told, I have a single phase 208V @ 40 amp circuit with #8 AWG. I believe the circuit breaker panel in the
computer room is a subpanel from a main panel in the hallway somewhere. At any rate, I also saw the following on the subpanel:
AMPS 225 VOLTS 120/208 PHASE 1 WIRE 3 TYPE NPA
The electrician said that some of the outlets are on phase A, some on phase B, each phase has 40 amps capacity and that I should not exceed
32 amps (80%) oneither phase. I've been trying to reconcile what the electrician said with what I saw on the subpanel in terms of the circuit's full capacity in amps so
that I'll know how much more equipment I can add. The main circuit breaker in the subpanel has 40 on it twice, I'm guessing 40 amps for each phase as I was
told.
I also came across the following equation in my research: 1 ton AC =
12,000 BTU/hr = 3516 WattsSo basically that would mean I can go no higher than 3516 Watts X 2 tons = 7032 Watts, certainly lower than that to leave headroom.
This leaves me with three questions:
1) How can I figure out the maximum amps of the circuit in the computer room?2) Could I just use the Kill-a-Watt tool to get a good measurement of my equipment's Wattage and then use the above equation to determine my BTU's?
3) If I knew the maximum capacity of the circuit, could I use the Kill- a-Watt tool and just keep my load less than 80% of circuit's capacity?Many thanks for any help in putting this all together,