Trunk slammer that was the plan to have a 350 cfm with 8 inch ducting pulling the hot air from the closet and bring it down to one side of the crawl space and a duct feeding from the other side of the crawl space bringing air in . I even had planned the inlet and out far apart to make sure the hot air wasn't going back to the closet . The issue with my plan was gc didn't want the 8 inch duct running down wall in mech room next door. it would have blocked the furnace shut off switch .

Reviving an older thread with a few questions:

1. I've used a couple Cool Cube 80cfm units for closets. Basically one amp plus a cable box - other components are cool (DVD, CD, etc). Units run most of the time. I'd think you'd want enough capacity to have the thing off at least half of the time. Is 80cfm even worth messing with?

2. Bathroom fan idea - requires we be electricians for a half hour; negative in some jurisdictions. Line voltage thermostats equal simplicity, but the ones I see stop at around 85-90 degrees, a little on the cool side, considering you might want it to turn off a little higher than that.

3. Again, bathroom fan would have to be a quiet but still 150cfm or more unit I would think. Are the above mentioned fans both powerful enough and quiet enough?

Seems to me that if the thermostat were lower in the rack or otherwise placed away from the heat, the effective temperature cutoff for the entire rack would be raised. Good old experimentation, often one of the first steps of "custom."

Fred Harding turned me on (above 90 degrees....) to a thermostat, enclosed in a box, with a power outlet. It works great. It's meant to be mounted on a duct and sample the air inside the duct. Strangely, when used out in the open, you pretend you want it to heat rather than cool, and set the temperature to the warmer temperature for a cooler environment. That is, it sets up backwards in free air.

It's a bit more than $30, but you'll have to contact Fred for the brand and model.

[Link: suncourt.com]

It looks viable. Probably need an outlet in the attic if you wanted to use this with a bathroom fan. Romex connected like you do for a flat panel when it's powered by your surge device.

[Link: snapav.com]

How about 80cfm for a closet with a Comcast box and AVR?

Where have you been putting the fans if they don't work? Did you remove the hot air from the closet, or just blow it around inside the closet? The last way doesn't work, period.

Just read through this thread quickly but I'm not getting something. It sounds like most are just including some arbitrary fans to exhaust some arbitrary heat. Are you guys really not taking the time to figure out how much heat your equipment is producing and equating that to how much air you need to move and exhaust in a cabinet, rack, or equipment room?

As a couple of folks have mentioned (and linked to), there are a lot of white papers readily available that teach you how to do this properly. It isn't hard and involves some pretty basic math skills.

We long ago started including power and heat loads as part of our equipment database and automated the whole process. A normal output of our engineering process is complete power requirements provided to sparky so we know we have enough power, and full heat loads calculated. If it is a smaller project, a small rack in a cabinet, etc. we handle the cooling ourselves. On larger projects, we supply the heat loads to the MEP engineer and / or HVAC company and coordinate for proper temperature, ventilation, and cooling of the larger equipment rooms.

Whatever you do, don't just guess. Figure it out!

Are you using specs or measuring the units in house?

Specs

This seems like it is easy to me. Has the HVAC company asked for a list of the power consumption of all the equipment? Have they asked what the allowed temperature rise is? Have they given you an analysis that shows what the temp rise is, for the equipment in the closet? If they have not done an analysis, then you simply send them and the homeowner a letter, detailing that you will not warrant the equipment in the rack, as the HVAC company is dictating a solution, without having done an analysis. You state that manufacturer's warranty may still be valid, but you will charge to remove and ship, and a charge will be present if they wish "loaner" gear. Stipulate that if equipment is shutting off due to overheating (without damaging itself), that you will not be able to fix that without the HVAC contractor fixing the heat situation in the closet. Refuse to install the rack and equipment until the homeowner signs off, taking responsibility, or until you get an analysis you feel is complete. I guarantee upon getting such a letter, the homeowner will be all over the HVAC contractor. The HVAC contractor will likely not be very happy with you... but then again they've been refusing to work with you anyway... so how can this be worse?

P2p ,
I did all of that when I started this thread . I spoke with the hvac company they agreed I had the right stuff . But to cool the room the closet I was affecting the hvac system in the whole house . There are so many other factors to move over 200 cfm of air you need a 6 inch ducts or bigger one .two you have to filter the air for dust . Three The air you draw in has to be from inside the living space so there isn't to much moisture . Four you can not have the inlet and outlet on same wall . have found that it is next to impossible to do all of these things builders just say they can't . I think you can only try your best and hope for the best

Sorry, I'm feeling dense here. Based on the diagram on this page: [Link: residential.fantech.net] I'm having trouble visualizing the placement of the three components of the Fantech when they are both drawing and returning to the crawlspace. All I can see in my head is a closed loop that goes THROUGH the closet without affecting the air in it. Can you clarify for me?

Thanks.

We ended up with a 130 cfm bathroom fan and it has done the job so far

Anyone ever found or used attic mounted closed loop A/C system?
I still need to do full BTU calcs, but I have a small closet ~6'x5' with couple of DA amps, 2 DVRs, etc. that I need to cool.
Rather than using a vent to push hot air to another room, and use living space as makeup air (which I can if I had to), I'd like to see if others have actual experience using 1 room A/C units.
Size would depend on load calcs, but figured I can look at specific model/size once I have the numbers.

BTW, this is for my own house, if that matters.

Deleted, old thread.

OK so the math is pretty simple.

(BTU per Hour) / (1.085 X DELTA T) = CFM

But how do you get the heat loss measurements? An amplifier rated for 1100w on the back isn't going to draw anywhere close to that.....and calculating it out, it yields a stupid high BTU number all on its own.

Total amperage x 400 = total BTU/Hr. @117v

I mean, I could guess. But short of powering up the units and driving some speakers and whatnot, how do you actually know?