Heat Removal by Ventillation
Heat Removal by Ventillation
(OP)
Dear Fellow ME's
We need to remove heat generated by computers from a very large room by ventillation only. I am looking for equations (method of calculations) or advise on how to calculate how much heat is removed. I can use fans to blow outside air into the space and exhaust air to outside. Heat generation is about 60,000 BTUH.
Regards
We need to remove heat generated by computers from a very large room by ventillation only. I am looking for equations (method of calculations) or advise on how to calculate how much heat is removed. I can use fans to blow outside air into the space and exhaust air to outside. Heat generation is about 60,000 BTUH.
Regards





RE: Heat Removal by Ventillation
If you know the temperature of the outside air, you know the delta T and can solve for 1 unknown (CFM)
RE: Heat Removal by Ventillation
Computer's generate only sensible load. If you're using a pile of outdoor air to remove load you'll be adding a latent load (humidity problem).
It is probably (definetly) easier to add a 5-6 ton fan-coil into the space.
RE: Heat Removal by Ventillation
We will use lots of outside air (20,000 CFM) of OA in Dallas, TX. How would the humidity effect this process if any.
RE: Heat Removal by Ventillation
RE: Heat Removal by Ventillation
Summer time the best you could do would be to keep the space a little warmer than it is outside.
Take the "V" out of HVAC and you are left with a HAC(k) job.
RE: Heat Removal by Ventillation
Regardless, I agree with Abby and Chris that you should use a cooling unit with filters.
Ventilation only in Dallas??
As Abby indicated, you cannot have the space temp lower than outside temp without some type of mechanical cooling.
ASHRAE DB summer temp 100 deg F
Most computerized electrical mfg max temp is 104 deg F
RE: Heat Removal by Ventillation
RE: Heat Removal by Ventillation
You must first decide what is your design space temperature before you arbitrarily tie into an existing system which may adversely impact the existing system.
Apparently the existing system was not designed to accommodate your space as a computer room.
Not knowing your existing room physical layout ---bite the bullet and install dedicated system---in the end you will be better off.
RE: Heat Removal by Ventillation
RE: Heat Removal by Ventillation
You need to figure out what temperature and humidity you want to maintain in the space. If the equipment gain is 60,000 there may be some gain through the envelope was well.
As a minimum I would guess you would be needing about a 7.5 ton system, and an air handler nominally rated for about 10 tons.
How critical is it if the cooling fails? You may want to consider redundant systems. You could design in a free cooling scheme as well, but as others have told you the first step is to determine what your exact load is and what conditions you want to maintain.
Take the "V" out of HVAC and you are left with a HAC(k) job.
RE: Heat Removal by Ventillation
When it comes to sensitive spaces, do not try to be a nice guy, spend your client's money, or he will be spending yours.
Use two AC units, one as stand-by, use the main VAV system for ventilation only.
The other thing is, you need to get air to the racks. A raised floor will do best if you can afford it.