Forum / Commercial HVACR / computer room heat gain question

## computer room heat gain question (9 Posts)

• ### computer room heat gain question

does anyone have a rule of thumb as to how much heat gain there is from a standard desktop computer, like you would have in your house? i have a job where the customer has moved their call center to an interior room within in their space. in this office there are four occupants, and six desk top computers. the size of the room is 280 ft2, 3920 ft3, the space has no exposed walls, and is served by a rooftop unit that serves other areas that require heat, and cool, where this room will only need ac year around. the six desktops are all the same model where on the back it shows 5 amps @ 120 volts. that would add up to 600 watts, and 2,046 btu's each. is this the best assumption to make as to how much heat these computers put out, or does anyone know a better way to go about this. thanks to all.
• ### Human heat emitters:

There's probably more heat given off by the humans when they are working in the room than by the equipment. They have a larger heat emitting surface than a computer.
Sounds like it is time for a Mini-Split. Properly sized of course.
• ### As usual, it depends

on the type and age of the computers and monitors.  Serious performance machines for CAD or gaming can easily draw 300+ Watts, while newer generation basic desktops under 50W.  Spend \$25 on a Kill-A-Watt meter and find out for sure.
• ### Kill a watt meter?

What is that, and what is the differance and using a regular volt amp meter to determine the watts consumed by this equipment, and it's heat output?
• ### Meters:

Kill A Watt meters are cool.
• ### AC Watts

Are not simply a multiplier of volts and amps.  There's a phase angle component (called power factor) which requires sampling over time and averaging.  Your meter will work fine for stable DC, but will not give you the right answer -- especially for nonlinear AC loads like a computer power supply.

http://www.p3international.com/products/p4400.html
• ### BTU's/Humans:

How many BTU's does a human give off while sitting in this room?
The act of human cooling (sweating) will add moisture to the air which needs to be removed for comfort?
There's a factor for it when cooling. In heating, it is an added source of heat. When cooling, isn't an added load for cooling?
• ### How many BTU's does a human give off while sitting in this room?

I do not know about when sitting, but when working about as hard as he can, a human can put out about 1/7 horsepower. I do not know if he can do that hour after hour or not. But that should get you into the ballpark.
• ### BTUs per person

Depends on the activity level http://www.engineeringtoolbox.com/persons-heat-gain-d_242.html
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