Getting cool air from attic to closet

[Rupp]

Guys,
My computer closet backs up to my attic. My computer closet is very small (3 feet deep X 6 feet wide) and it heats up during the winter. I have an air conditioning vent in the closet so summers are not a problem. What I would like to do is somehow put in a "device" that will open at night when the temps in the attic are cold but shut during the day when the temps warm up. Any suggestions?

[jackpod]

Humm, I am assuming that this vent is standard HVAC which would mean when the furnace comes on it blows hot air into the closet?

About the only thing I could think of is installing a vent fan like what is in the bathroom and control it with like a 1wire temp sensor. Bathroom vent fans don't close the vent when not on and hot air rises, so it would be a constant source of ventilation, assisted by the fan when the temp sensor reaches a certain threshold

[Gogs]

Rupp, an over simplistic idea.

Get hold of an old small fridge. Strip it down to the bare essentials so that it will fit. switch it on and off by a temp sensor, connected or not to HS, and make sure the cooling element is at the top of the closet. (Hot air rises), or to cover all angles get two old fridges and have one at the bottom and one at the top.

You could also store your wine in there!

PS. Don't forget the drip tray.

Of course if HS fails because of overheating the fridge element will never start or switch off, we could find out in just what cold temperatures HS will work, but that's life, no?

[nightwalker]

I would almost think that a plain ole exhaust fan, mounted opposite from how you normally mount would work. Mounted with the fan in the attic space and the butterfly cover in the closet and controlled by an event based on temp or time or both.

[BraveSirRobbin]

http://www.automatedoutlet.com/produ...2&cat=0&page=1

[joeslat]

I had a similar application to what you are asking for and used exactly what BraveSirRobin suggested above. I use scripts to "know" if the HVAC is blowing air, heat or A/C and the vent opens/closes by HS tripping a contact. The install was almost over my head, but the help from Automated Outlet was gret. Works great. I was thinking about expanding this application to more HVAC vents but never got around to it.

Joe

[nsisman]

Rupp,

I think you might need to be a little careful doing this ?

Just remember freezing cold metal (or plastic) pipe in attic meeting heated air from closet in the dead of winter means condensation - lots of it !

Water dripping on to computer racks and electronics not a really good combo ?

Maybe you don't get cold down there ?

Neil

[Rupp]

I had a similar application to what you are asking for and used exactly what BraveSirRobin suggested above. I use scripts to "know" if the HVAC is blowing air, heat or A/C and the vent opens/closes by HS tripping a contact. The install was almost over my head, but the help from Automated Outlet was gret. Works great. I was thinking about expanding this application to more HVAC vents but never got around to it.

Joe

Joe,
My application is much more simple. I manually close the air register when cooling season is over. So that doesn't need to be automated. I currently step into my computer closet every night and open a door that's in the back of my computer closet to let cold air in.

[Rupp]

Humm, I am assuming that this vent is standard HVAC which would mean when the furnace comes on it blows hot air into the closet?

About the only thing I could think of is installing a vent fan like what is in the bathroom and control it with like a 1wire temp sensor. Bathroom vent fans don't close the vent when not on and hot air rises, so it would be a constant source of ventilation, assisted by the fan when the temp sensor reaches a certain threshold

This duct for the air is shut off after cooling season. This is just twice a year thing. So all I need is a way to get cool air in from the attic to the closet. The bathroom vent fan sounds like a good idea.

[Rupp]

http://www.automatedoutlet.com/produ...2&cat=0&page=1

I guess I could use this in the wall between the attic and the closet. My only concern would be, will enough cool air get through?

[outbackrob]

Return duct.

Instead of using a forced air duct, why not hook it up to your return air system? It will always suck warm air out of the closet all year long. It does not add much heat in the summer and will sort of pre-warm air in the winter. No condensation issues either. I have a filter in line to keep dust out of the system. It works very well. Set and forget.

[joeslat]

OK, let me explain more fully what I have. I have a duct going from my HVAC directly to my HA system closet (telco, Elk, HS server, patch panels, etc.). This duct has a manual on/off, which I close fully whenever we begin using the heater for the winter. The HA closet also has a vent to a closet next door, where all my A/V equipment is and some other PC's, and in the closet next door, there is a return to the HVAC. Both the duct to and return from the HA closet are very short runs from the HVAC, so I get great flow/suction.

Covering the inlet into the HA closet is the automated duct, which is controlled by the Elk Output 3 contact. Homeseer knows what the HVAC system is doing (Heating, Cooling, Fan only, Fan Off). Here are the event conditions when the HVAC is in the followin status:

"Heating" - the vent gets closed (and stays closed for 5 minutes after heating stops to clear the ducts)
"Cooling" - the vent is open
"Fan only" - typically open
"Off" - closed

So, I get cool air when it is available, and when the vent is closed, the return will pull some air from under the doors, etc. and bring some cooler air into that closet. I also have multiple temp sensors in that closet with some high-temp warnings. Typically, I can keep that closet to <82 degrees, which is pretty good considering all the gear wizzing in there.

Joe

[anogee]

I don't have a solution, but you should never breach the fire barrier between your attic and your living areas. Your ceilings have a special fire-rated drywall for a reason. If you really want to vent to the attic, you should get a special fan/vent for that purpose. These have a thermostat which closes shutters in the event of a fire. (They make garage vents for that purpose.)