Cabinet cooling question

[Towen7]

All f my HT and network equipment is in an enclosed cabinet at the back of my room. As you would imagine it gets hot in there. So hot that I have to keep the doors open when watching/listening for any length of time. Even with the equipment off I have issues. So...

Would it be more effective to exhaust the hot air into the attic space or the AC return, or would it be better to force cold air (from an AC duct) into the cabinet?

 

[DIYer]

^ Whichever makes less noise.

 

[Zing]

Would it be more effective to exhaust the hot air into the attic space or the AC return, or would it be better to force cold air (from an AC duct) into the cabinet?

Is it feasible to do both? If not, I think the most effective action would be the latter because you'd be cooling the source of the heat, thus reducing heat and the need to exhaust it.

 

[Yesfan70]

I would try the hot air to an attic. Forced cold air sounds good too, but then you're giving up a register to cool your equipment.

The return duct? My guess is your thermostat might be tricked to turn on more often. That might be negligible, but I wouldn't be surprised if you noticed it running more if your rack puts out that much heat. That's why it would be my last choice.

 

[Rope]

To effectively cool electronic components in a enclosure, the warm air should be evacuated at the rear, or top of the enclosure. Consequently the cool air will be drawn in simultaneuosly from the front.

Rope

 

[Towen7]

I can do both and without taking away a register. Is that best?

There is a vertical duct-run behind the righ rear corner of the room. Tapping a flexible line into the cold air supply would be easy. I'd run a line through the lower cabinet and across to the bottom of the rack. Ditto for the exhaust. The line would run from the top of the rack, down to the lower right cabinets and horizontally to the attic space.

Here's an old pic to give an idea of the layout.

 

[Zing]

I can do both and without taking away a register. Is that best?

Unquestionably.

 

[Botch]

Doesn't the equipment cool itself as it falls to the floor? :teasing-tease:

 

[Towen7]

Great point!

At the frequency that happens around here my equipment should be ice cold.

 

[Rope]

Keep in mind when you're really jammin' you'll still need to leave the cabinet open at the front so the cool air can be draw in.

Rope

 

[PaulyT]

Seems to me there are two questions here: keeping the equipment cool, and keeping the room cool. The former is done by circulating cold air into (and necessarily out of) the rack cabinet. The latter is done by venting the warm air from that cabinet (e.g. the heat generated by the equipment) out of the room somehow. Unless you can do both, there may not be much benefit.

 

[Towen7]

Keep in mind when you're really jammin' you'll still need to leave the cabinet open at the front so the cool air can be draw in.

Even with a cold air line plumbed in from the AC?

Seems to me there are two questions here: keeping the equipment cool, and keeping the room cool. The former is done by circulating cold air into (and necessarily out of) the rack cabinet. The latter is done by venting the warm air from that cabinet (e.g. the heat generated by the equipment) out of the room somehow. Unless you can do both, there may not be much benefit.

Makes sens. The room does get hot, especially in the late afternoon. I don't know how much of a heat load the equipment is adding t the room but removing it can only help.

I'll start looking for thermostatically controlled exhaust fans to mount in the attic and for a bunch of flexible 4" ducts.

 

[Rope]

Keep in mind when you're really jammin' you'll still need to leave the cabinet open at the front so the cool air can be draw in.

Even with a cold air line plumbed in from the AC?

Seems to me there are two questions here: keeping the equipment cool, and keeping the room cool. The former is done by circulating cold air into (and necessarily out of) the rack cabinet. The latter is done by venting the warm air from that cabinet (e.g. the heat generated by the equipment) out of the room somehow. Unless you can do both, there may not be much benefit.

Makes sens. The room does get hot, especially in the late afternoon. I don't know how much of a heat load the equipment is adding t the room but removing it can only help.



I'll start looking for thermostatically controlled exhaust fans to mount in the attic and for a bunch of flexible 4" ducts.

I doubt the air in the room is as warm, or warmer than the air inside the cabinet.

Where is the A/C inlet on the cabinet? If the evacuation of warm air is at the top, the A/C inlet should be at the bottom and the front doors should remain closed.

Rope

 

[Towen7]

There is no inlet or exhaust yet. If I do the I'd mount the exhaust duct at the top-right of the cabinet. The exhaust duct will run to a fan in the attic (switched on by a thermostat in the rack). The AC inlet would be mounted on the bottom right of the cabinet.

In a perfect world the inlet and exhaust would be on opposite sides, I know. I just don't have the space for that.

 

[Rope]

There is no inlet or exhaust yet. If I do the I'd mount the exhaust duct at the top-right of the cabinet. The exhaust duct will run to a fan in the attic (switched on by a thermostat in the rack). The AC inlet would be mounted on the bottom right of the cabinet.

In a perfect world the inlet and exhaust would be on opposite sides, I know. I just don't have the space for that.

That should work beautifully. To make it more efficient you could use a push/pull, or a fan at the bottom (cold air sinks)to push the cold air up and you already have an evacuation fan in the attic.

Rope

 

[Flint]

I use an exhaust into my attic for my equipment closet. I put a 4" PVC Pipe in the ceiling of the closet and clamped a flexible vent duct for bathroom vents to the top of it. I then ran the vent duct to the side and around where I attached a small MDF board with a PVC flange on one side and a 4" AC PC fan on the other sucking hot air out of the closet.

Why?

1) The vent in the ceiling is for the hot air which rises.
2) The PVC pipe is easy to work with and easy to find at any hardware store.
3) The Vent Duct is easy to find, easy to work with, and affordable.
4) The length of twisting duct significantly reduces the noise in the closet from the fan which can be pretty loud.
5) The fan is affordable, easy to replace, and runs 24-hours a day on AC power. I get power to it via a re-purposed old extension cord I cut the recepticle off.
6) I suck air out of the closet (that than push it in) because it is always better to create a vacuum when cooling which reduces the pressure in the closet and when air is sucked in from the slightly higher pressure outside room it cools immediately as it passes to the lower pressure closet.

It works like champ.

In the 6 years, or so, that I've had this setup I had to replace the fan last Spring - so about 5 1/2 years for the first fan. Not bad.

 

[Towen7]

I'm with you on the idea of exhausting from the top to the attic. I dont have near the volume in my cabinet that you have in your closet. I was worried that just exhausting hot air wouldn't be enough and that adding cool air would be required.

I guess I can try the exhaust alone and add the cold air line if it's still too hot.

 

[Flint]

It would be easy to add a second exhaust fan to the vent duct.

Don't push air in, always suck it out. It makes a difference.

 

[Orbison]

I don't think exhausting hot air into a hot attic is going to be as effective as tapping a return duct to pull hot air out of the cabinet - it would also eliminate the need for an exhaust fan. That assumes, of course, that the A/C is running most or all of the time.

:twocents-mytwocents:

 

[Rope]

Rope