Oak AV cabinet cooling

[Durzel]

Hi

I recently bought an oak AV cabinet to put my HTPC and NAS in. The cabinet has a pretty large hole at the back, in the middle, to run cables through.

It seems I vastly underestimated the heat output of my HTPC, as it’s basically cooking itself inside the cabinet. If I leave the door open it’s manageable - but the CPU temps are still in the high 60s, at idle. When it’s actually doing something it goes up to 75+, and with the door closed it will go over 80C. Clearly too hot.

I haven’t even got the NAS switched on yet, so that will undoubtedly warm up the cabinet even more.

Anyone got any suggestions for some ways to cool the inside of the cabinet down? I’ve seen AC Infinity fan kits recommended on another forum - can anyone vouch for them?

Here’s what it looks like:



I don’t think I could mount anything to the sides as it would foul the glass shelves inside, unless the fans (or whatever) were on the outside - which I think would look a bit crappy.

Thanks in advance.

[Sporky]

We get this a lot at work. Interior designer insists on coming up with a cabinet, forgets cooling.

I'd try adding holes at the bottom and top so that you get a natural chimney effect - hot air rises out of the top, draws colder air in at the borrom.

[joshleb]

I've used a couple of the AC infinity fans before to suck the heat out from the PC before, worked well enough.

Any scope to cut a hole in the back and add some fans to it or keep it passive?

[Durzel]

Thanks.

Stupid question but when you say the bottom and top I assume you mean drill some holes in the back of the unit, rather than literally holes in the bottom panel (that the NAS is resting on), and top?

As you say this thing was designed with a hole for cables, but absolutely zero other holes for cooling.

[Durzel]

joshleb said:

I've used a couple of the AC infinity fans before to suck the heat out from the PC before, worked well enough.

Any scope to cut a hole in the back and add some fans to it or keep it passive?

Yeah there’s some room at the top at the back, above the highest position you can mount a shelf.

I was hoping to not have to cut big holes into it myself, as I don’t have the skills or the tools, but it looks like it’ll be necessary.

Do you think it needs a push/pull config with fans at the bottom and top? Or would exhaust be sufficient normally?

[Sporky]

Durzel said:

Thanks.

Stupid question but when you say the bottom and top I assume you mean drill some holes in the back of the unit, rather than literally holes in the bottom panel (that the NAS is resting on), and top?

Literally top and bottom is best (assuming air can get to the bottom) but the main thing us hit will naturally go out at the top, so cold will naturally come in at the bottom.

Fans may be needed too, but don't fight the thermal chimney effect.

[UpTheIron]

My AV preamp used to trip out due to overheating in a similar setup.

I cut the back out the cabinet, still not enough.

I put a hole in the floor and a USB powered (silent) PC fan to pull an airflow and no problems since .

[Durzel]

Thanks all, that gives me something to think about.

Not sure how the “thermal chimney” effect would work, is that just holes with no fans? I don’t really want to cut holes in the actual top of the unit, as that would look unsightly I think.

Edited by Durzel on Wednesday 4th August 22:34

[dmsims]

Cut holes in the floor and at the back (vertical) face (as near to the top as you can)

[Sporky]

Durzel said:

Not sure how the “thermal chimney” effect would work, is that just holes with no fans? I don’t really want to cut holes in the actual top of the unit, as that would look unsightly I think.

Yes. Might be enough airflow to solve the problem, might need some fan assistance.

The holes don't have to be in the top itself (thought that's the best place), but the upper holes need to be as high up as possible.

Or you could put holes where the PC's fan outlet is so it's not heating the cabinet itself too much.

[Tony1963]

Just so I know I’m seeing the picture correctly, can you confirm that the glass shelves are a flush fit to the left and right sides of the cabinet, and almost flush front and rear? If so, it’s the glass shelves that need holes in, otherwise you’re almost sealing the electronics against warm air rising.

[Durzel]

Tony1963 said:

Just so I know I’m seeing the picture correctly, can you confirm that the glass shelves are a flush fit to the left and right sides of the cabinet, and almost flush front and rear? If so, it’s the glass shelves that need holes in, otherwise you’re almost sealing the electronics against warm air rising.

Yeah, the glass shelves are flush to the sides, and almost flush to the back.. it's enough space to get a network and power cable behind (the cables, not the connectors on the end) but that's it.

The problem with having anything that intrudes into the unit is that the shelves are movable, so down the line I might end up reconfiguring it to hold different units. If the cooling system prevents the shelves from being fitted to certain mounting points (you can make the holes out in the photo) then that will create another problem.

I can get away with mounting something on the rear at the bottom and the top, because the shelves can only go so high or low, but anything mounted to the side (unless the fans are mounted on the outside of the cabinet, which would look pretty crap) is out.

My current thinking is to have one of these at the bottom rear of the unit, blowing air into the cabinet, and another one at the top rear of it, in exhaust config? Would that work?

Edited by Durzel on Thursday 5th August 13:00

[Sporky]

I think that'd certainly make things better - just make sure the air can move around inside the cabinet too.

[Durzel]

Ok I'm trying to think about a few different options here.

The issues I've got are:

• The glass shelves are essentially flush to the sides, and almost flush to the front and back - there's maybe 1/2 cm gap at the rear, for cables. Not sure how much space there is from the shelf to the door of the cabinet, but it's probably a similar amount.

• Because ths shelves are flush, I can't mount anything to the sides or back that would intrude on the interior of the cabinet, unless it is fitted to the very top and the very bottom of it, because the shelves can only be mounted so low or high.

My current thinking was to mount a 3 fan push and 3 fan pull system in the rear of the unit, in the areas at the top and bottom where you can't fit the shelves. The primary issues with this are that the NAS at the bottom has an exhaust fan that will be blowing against the air being blown in, and the glass shelf above it (that the HTPC sits on) may well block almost all of the air from reaching that compartment, and the one above it (although the switch is passively cooled). I don't think making holes in the glass shelves is feasible - I certainly don't have the skills to do it.

Another option I'm thinking about is mounting 3 sets of 3 fans on the rear of the unit, on the outside, with only the grill part on the inside (so not fouling the shelves), with each combo of 3 fans in a push and pull configuration. On the basis that holes in the bottom of the unit that draw cooler air in might not get above the first shelf, perhaps a 3 push/pull config would work better?

Another option - not sure if it would work - is a variation on the above where the fans are just exhaust. Perhaps I could get away with only one fan per shelf (I have to be mindful of the fact the shelves might be reconfigured with different equipment). This would create a negative pressure environment though, so not sure where the outside air would be drawn in.. presumably through the gaps in the wood at the front of the cabinet?

Interested to hear thoughts on the above..

[dmsims]

Way too many fans, one hole in the bottom, one at the top with 1 fan

[Durzel]

dmsims said:

Way too many fans, one hole in the bottom, one at the top with 1 fan

You think the air will get past the shelves, with only ~0.5cm at the front and back? Even if it does, the air won't flow over the individual components, I guess? I might be overthinking it.

[Tony1963]

Op,

As a trial, replace the glass shelves with mdf/plywood shelves with a few holes in. See how the temperatures go with that simple mod.

The trouble with using fans to extract warm air is that the cooler replacement air has to come from somewhere, and it’s more efficient if it’s a natural flow. Your electronics are trapped in cells that are sealed on five sides out of six, so you’re not going to achieve much if you only extract at the rear with no other mods: air in the cells could just sit there, not moving.

I’d buy a more suitable table/cabinet, cut my losses.

[Tony1963]

dmsims said:

Way too many fans, one hole in the bottom, one at the top with 1 fan

That won’t achieve anything. The air in each ‘cell’ just won’t move.

[Northernboy]

Durzel said:

Thanks.

Stupid question but when you say the bottom and top I assume you mean drill some holes in the back of the unit, rather than literally holes in the bottom panel (that the NAS is resting on), and top?

As you say this thing was designed with a hole for cables, but absolutely zero other holes for cooling.

For mine I drilled 50mm holes in the bottom and then two rows in the back, one at the bottom and one at the top of the rear panel.

[RizzoTheRat]

The shelves are adjustable height, but in order to be useable as a shelf it's always going to a reasonably distance from the top. You can get 120mm fans like you'd use in computer cases but powered by USB so no additional power needed. They're only an inch or so wide so possibly could mount on the outside of the cabinet rather than the inside if worried about the space for shelves. Mount one as high up as possible on the back of the unit and them some holes in the bottom.
Airflow between the shelves could be an issue though.