Keeping electronics cool in enclosed spaces?

January 4, 2007 1:56 PM

What is the best way to keep electronic devices that are in enclosed areas cool? (ie. stereo receiver, game console, etc). I'm just got a new AV cabinet/stand that is a lot smaller than my previous one and my components are getting a lot warmer than they used to. My receiver has about 1" leeway on each side and about .5" on top. 1/3 of the rear of the cabinet is open. I also have my HTPC in there as well as my Xbox 360. Anyone know of a simple way to keep them cooler (without adding noise or uglyness to my setup)? Would not like to cut anything. Some ideas... Separate the exhaust and intake (so no hot air gets recycled) by blocking the sides and top at the rear of the unit. Put a small computer fan at the back of the stand to improve airflow? Put a exhaust hose (a la dryer) on the receiver where the fan is.. maybe put a fan at the end of the hose to pull more air through? Any tried and true methods that arent too complicated?
posted by mphuie to technology (6 comments total)

Wow my bad, must have typed the text in the wrong box...
posted by mphuie at 1:57 PM on January 4, 2007

Outside of fans [noisy] and following the manufacturer's recommendations [ever notice how the manual for each component advises to keep a couple of inches clearance above, despite everything being designed to be stacked?], you need to think about where the heat comes from and where it goes.

1. Most of the heat comes from the back of the equipment.
2. Warm air rises.

In most cases, stacking things so the biggest heat producers (amp, etc) are at the top, and putting a panel across the middle 1/2~1/3 of the back - leaving the upper and lower thirds or quarters open for air flow in at the bottom, out at the top - is sufficient passive cooling.

Since your receiver already has a cooling fan, I'd be tempted to duct it out - but I'd probably decide to try it without, then forget about it...

(Oh, and for maximum cooling effect, keep the front doors closed. You want the air coming in, past the warm bits, and out. A big opening at the front just confuses things.)
posted by Pinback at 4:11 PM on January 4, 2007

The problem you have is horrendously complicated, partly because the risk of a problem is low but never zero..

There are major sources of heat, like the main power transistors in the amplifier section of your receiver, or a CPU in a HTPC - these are often cooled with a fan - but you also have to consider minor sources of heat which nonetheless run hot, and may fail when running in a hot environment.

For major sources of heat, if the fan is running all the time, it would be helpful to find a way to direct that airflow straight out of the cabinet (with a duct, or baffles, or whatever). However, your receiver's fan probably doesn't run very often at all, because you probably don't turn the volume up that loud. Obviously directing non-existent airflow is kind of pointless.

For the minor sources of heat, it is important to keep the overall temperature everywhere inside the cabinet at a reasonable temperature. This is because you never know where the hot part is located in a device. This would be a particular problem if a hot part happened to be right where you have placed a block to try and manage the airflow. So, don't block the sides and top unless you are very certain of what you are doing.

It is important to understand what you need to solve. Is it too hot while the cabinet is closed, even though most of the gear is in stand-by mode, or is it only getting hot after a couple of hours of use? Are you leaving the cabinet doors closed while the gear is in use, or do you open it up to improve the airflow?

Putting a big diameter slow turning fan in the hole at the back will help a lot, and it won't be very loud. Placing the fan so that it assists the natural convection current is critical. Also, try to keep track of where the air comes from and goes to in general, because as you suggest, sometimes fans can just recirculate the heat.
posted by Chuckles at 4:54 PM on January 4, 2007

(Oh, and for maximum cooling effect, keep the front doors closed. You want the air coming in, past the warm bits, and out. A big opening at the front just confuses things.)

:)

Maybe.. You have to have a nice easy path for air to get in at the bottom, preferably the bottom front. If the doors seal too tight, you'll have a big problem - if I had to guess, anything less than a ~1" wide gap across the bottom of the doors, all the way across, is probably sealed too tight.
posted by Chuckles at 4:59 PM on January 4, 2007

There really is no trick to this; you just need to arrange for cool air to enter the cabinet and hot air to leave.

Which third of the rear is open? Because if it's only the top third, then there's no way cool air is going to find its way into the bottom of the stack.

I know you said you didn't want to cut anything. But if I owned that cabinet, and heat was giving me grief, I'd make sure that there was a big gap at the bottom for cool air to come in, as well as one at the top for warm air to go out.

You might be able to achieve this without cutting, depending on the cabinet construction. If the rear panel is stapled on, pull the staples and reattach it further up. If it sits in a slot in the woodwork, you might be able to encourage it upward without even needing to staple anything.

If that wasn't enough, I'd replace the back panel entirely (they're usually just a sheet of thin MDF, which is cheap and easy to replace) with one that had a 2" slot running the full width at the bottom, and a quiet extractor fan (Papst make some you can scarcely hear) mounted in a hole near the top.

If any of your existing equipment is already fan-cooled, putting the fan-cooled devices at the top of the stack, and ducting their exhausts to force replacement air to come in through the cool-intake slot at the bottom, would work as well as a separate extractor fan and not add noise.
posted by flabdablet at 5:10 PM on January 4, 2007

You could go to a computer parts supplier, buy a silent fan, hook it up to an appropriate power supply (12v AC adapters are pretty common) and attach it in the back. A bit of panelling, a few holes in the right place or opening up some panels such as flabdablet says, and you should have no problems.
posted by tomble at 11:18 PM on January 4, 2007