Outage

Use PC fans to keep your gear cool


Anyone who has more than a couple devices running in their living room or home theater knows that those devices can heat up very quickly. In my case, I have an XBOX 360 and a DirecTV H20 HDTV receiver that get way too hot. Keeping all of that heat trapped within my home theater equipment rack will shorten the life of those components.

After doing some research on ready-made cooling solutions which can cost $100 or more, I decided to create my own. With about $30 in parts and an hour or two of labor, you can make a DIY cooling system for your home theater.

The parts list:
  • 1.5-12V Regulated 300mA AC Adapter This will provide the power for your fan(s). I got mine at Radio Shack for around $17. Here is a similar model for $19.
  • Hobby power leads These will allow you to connect your power supply to your fan(s). Again, got mine at Radio Shack for around $3.
  • PC fan(s) I used 3 fans in my setup. You can grab these from NewEgg for around $5 each.
  • Y adaptaplug (optional) This allows you to split the cable from the power supply to support more than one fan
The tools/supplies:

  1. Soldering gun
  2. Electrical tape

The process:

  1. Solder the wires from the PC fan to the wires on the hobby leads
  2. Wrap the exposed portions of the wires with electrical tape
  3. Plug the hobby lead into the outlet on the power supply's cord
  4. Attach some velcro to your fans
  5. Attach some velcro to your equipment rack
  6. Attach fan to equipment rack using... yep, the velcro from steps 4 and 5.

Fans

3 fans wired to the 12v power supply. I eventually wrapped all of the wires in black electrical tape so that they wouldn't stand out.

Tweaks:

Of course, PC fans running at full speed can get noisy. That's where the adjustable power supply comes in. You can adjust the voltage of the power supply to run the fans at a lower speed. This will reduce the fan noise while still providing enough air flow to cool your components. You will need to play around with it until you get the right balance of noise and air flow.

Another little trick is to connect your power supply to a component with a switchable outlet like a home theater receiver. This will allow the fan to shut off when you power off the component. Otherwise, you will have a fan running constantly. Of course, for some components, like my DirecTV H20 receiver which is always on (even when you turn it off), you may need to have a fan going all the time.

You may also want to experiment with the direction of the air flow. I have found that blowing air across the top of my DirecTV H20 works better than trying to pull air out of the back of the equipment rack. However, for the XBOX 360 which has a rear exhaust fan, a fan pulling the hot air out the back of the equipment rack works much better.

Results:

I was able to reduce the overall temperature in my equipment rack significantly using 3 PC fans running at 9v. Everything, with the exception of the XBOX 360, runs at approximately the same temperature when powered on as when it is powered off. If you have $30 and a few hours to dedicate to the process, you can keep your components running cooler and extend their life by adding a few cooling fans.

32 comments
firestorm69
firestorm69

Now I'm sure that most IT people, like myself have spare or old computers or at least the parts of them. I'll just grab an old power supply out of one of my spares. Then I mount it in one of those cheap throw away plastic containers they sell at supermarkets everywhere and cut vents in it for the built in fan using a razor or exacto knife. You can paint it and even use the grill covering the fan to cover the hole in the container (if the power supply has a removable grill, some just integrate it into the metal casing). Just one hole for the fan and some slits or series of holes (a soldering iron is great for making a bunch of small holes) on the other sides and lid. Run the wires out of the container. Then you can even use the old fans from the same old spare you got the power supply from and plug them righ in with no soldering required at all. All the screws you got from the spare can also be used for the mounting of the equipment in the plastic container. You can use a wrapped cable to connect all the fans, I found this with a quick goolge search: http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=82&products_id=336 and can even choose different colors. For speed control, a cheap control switch can be found, like this one I found: http://www.directron.com/fcontroller.html and can be mounted in the container with the power supply as well. All in all, very easy to make and very inexpensive. Also a fun little project in your down time (if any). Let me know what you guys think. Also, just in case the cheap plastic containers can't take the heat of the power supply, you can easily build one out of wood or what every you like. Jamie

boomchuck1
boomchuck1

I do amateur astronomy. Although I havent' done this myself I know a lot of people that have taken these little fans and mounted them in their telescopes - usually ones with a mirror 8" or larger - and use them to help cool the mirror down or blow across the mirror to remove warm air from the surface of the mirror. A warm mirror will create convection currents that actually distort the image in the scope. These are just a couple ways to cool the mirror down to the ambient temperature.

lmc@LostGround.net
lmc@LostGround.net

Cool! Last summer I noticed my computer with LED fans was filling up with mosquitoes. I thought it would be a most excellent joke to build little LED fan mosquito traps and scatter them around the yard. Couldn't get beyond the PSU issue. This solves that -- hey, how 'bout Solar? With parts raided from a solar light, including the storage batteries and the sensor that turns it on at night....

coyt.watters
coyt.watters

Nuts N Volts just ran an article in this month's issue to build a temperature controlled fan speed controller, which fits right in this project. Instead of manually tweaking the fan speed, this circuit uses a thermistor to detect the temp, and as it rises the fan speed is increased. Might be worth checking out. www.nutsvolts.com (just a subscriber)

LawrencRJ
LawrencRJ

I have a HP-ZD7000 (nice little laptop that just went over the extended warantee before it started spontaniously shutting down and coming back on. I went to Staples where there was an HP laptop with a great rebate. It seeemed a shame that I "needed" to relegate this perfectly working 17" laptop to the role of a doorstop, but I bit the bullet and purchased the new one ... Lucky for me they had screwed up on formattiung the 160 Gig hard drive so that it only had 76 Gig usable. When I took it back the salesman told me on the QT that probably the problem with the old one was just an overheating problem. He suggested that I try it in a really cool place with a breeze to see if it still powered off and on spontaniously. I took the back off and ran it overnight next to the air conditioner outlet and it was still running a program in the morning, so I know it had not powered down. In reading your post (and the comments) I came across the reply about using the fans from old dead desktops (which I have 3 of in storage.) But since it is a laptop I need to have my hookup run off batteries (to make it usable where there is no AC power. I discovered this yesterday and today I read your article -- talke about synchronicity -- it is almost spooky. Richard J. Lawrence Plattsburgh, NY

Foggiest
Foggiest

Excellent info! Three questions: 1. Since air pressure affects heat transfer, how much of a difference would it make to blow cooler air IN rather than pull warmer air OUT? Or is this too insignificant an effect? 2. If space is limited, what are the effects of using two fans in series, either one right behind another, or one in, one out? 3. Finally, what is a "blower"? Is this a squirrel-cage thing like in my furnace, rather than a bladed "fan"?

jdclyde
jdclyde

I have wanted to do something like this for a long time, but just was too lazy to get around to it. Always have other things that "need" to be done, ya know? Of course, noise is a concern, so may look around for a different fan. How many bearings should a quality fan have? I see the one linked to is a two bearing system.

JimTheEngineer
JimTheEngineer

It is a good idea to use a filter on the incoming air, and to use an arrangement that keeps the cabinet pressure slightly higher than ambient. One hint that I got from talented technicians who built what I designed - make the filter visible to the equipment operator. When the filter got dirty and started to look like some evil writhing hairy thing, the operator would make sure that the filter was cleaned. In an Audio-Video installation, a tasteful grill over the intake (with the filter right behind it) wouldn't be too offensive to the decor.

crpope10
crpope10

for $30 and a couple hours of your time you've created a possible firetrap that leaves you entirely liable for the disaster. Frankly, my time is more valuable than that and I don't want any of the liability issues.

ken lillemo
ken lillemo

For this design, I recommend an inline fuse to avoid the emabarrasing arcing that occurs when you pinch the lead wires when sliding a piece of gear out of the cabinet. I used to do things like this without fuses, but now incorporate them in all my designs.

TexasJetter
TexasJetter

I have a Media Center PC in my Entertainment Center - I ran a cable from inside the PC case to the external fans. That way when I turn the PC on the fans blow automatically. I did have to run through an external speed controller because the fans were a little to loud at full speed. As a bonus I used fans with LEDs - it make a cool glow inside the case :) I have also considered ducting the exhaust of the equipment to outside the case. Something like connecting a duct to the back of the power supply and case fans just to get the heat out of the enclosure - any thoughts about this?

mdhealy
mdhealy

Radio Shack also carries some 120-volt fans, so if one doesn't need the speed adjustment using one of those reduces the parts count -- for some years I've cooled a system that way. In addition to the little fan, one needs only an old extension cord and a little switch.

abidullah.mahmood
abidullah.mahmood

Be carefull with the direction of the fans. the fans used must flow/blow the air stream in a uniform direction i.e. across your cpu towards the back part of the casing. The next important thing is that always leave some space (6 inches minimal) behind your cpu and any other object, this allows the hot air to disperse before it may re-enter in the cooling cyccle.

dbear135
dbear135

The use of shrinky dink tubes will look neater than wraping the wires. It's also available at Radio Shack! ...............dbear135

acmp
acmp

AS you've already had the lid off your laptop I'll assume you know where all the screws are... Inside somewhere is your cooling fan. If it is a big laptop there may be 2 fans. Take it to bits, find the fan turn on the laptop and see if the fan works. If it does not run or is noisy/rough it needs replacing. Get the part number from the fan and look it up on ebay. Someone will be selling them. Buy one for a few $'s and fit it yourself. If it works then you've fixed it, if not you've only wasted a few $'s It's also worth cleaning the air duct/heat sink just in case it is a simple dust blockage issue. Best of luck

Nico_Baumgarten
Nico_Baumgarten

I also have a HP ZD7000 running usually all day. I did have a very similar problem of it heating up resulting in blue screens and rather unreliable behaviour. I bought one of those usb powered laptop cooling pads, which helped a little but not much because they are usually to small for this model. So I finally opened up the laptop and cleaned the cooling system. If you dont do this once yourself you wont believe how much dirt was in there!!! Since, the laptop is running smoothly again for now over 3 months again.

boomchuck1
boomchuck1

We had the same problem with a HP dv1000 laptop, but rather than kludging something together we took it in for repair. About $150 to fix the overheating problem and it runs as good as ever. Yeah, $150 hurts but it's a lot better than buying a new one when otherwise the machine works just fine.

rdcpro
rdcpro

I have a Fujitsu laptop that generates TONS of heat as well. It can blue screen if left to it's own devices. You can buy a USB powered plastic base that you set the laptop on. It has multiple fans in it that blow air onto the base of the laptop. It works fantastic! And a bonus is that I have a nice flat platform on which to rest it when I'm actually using the laptop on my lap. Here's an example: http://meritline.stores.yahoo.net/laptop-cooler-3-fans-4-usb-port.html I have no knowledge of that particular model or seller-just a random link. But you get the idea. Regards, Mike Sharp

sMoRTy71
sMoRTy71

cause I was planning on running that at a lower voltage. Plus, I was just going for the cheapest option. So far, I've found that your basic PC fan, when running at half its normal voltage, is pretty quiet when no other devices are on. Of course, once I crank up a movie or something that uses my A/V receiver, you can't hear them at all.

marquis
marquis

can be readily obtained from old power supplies, CPU coolers, and such. They are generally 5VDC, sometimes 12VDC. Usually free, if you're a "junk collector" like me. And old PC's can be obtained for the taking away. If you're putting the fan(s) in or near the PC, use a Y connector, solder the leads from the fan to the extended lead/connector (again, salvaged), and plug it into the Y. Bingo. Cost: close to $0.00. If you're real handy and inventive, make a variable voltage controller and dial in a "quiet" operating speed.

acmp
acmp

Surely as we are talking about low voltage dc equipment that is powered from a double insulated sealed power supply there is no chance of this causing a fire. You could short the output wires and not cause an damage other than breaking the power supply. The energery and heating caused by this most disasterous act would easily be contained within the power supply and not damage any other equipment. Of course if you go down the mains voltage fan route you will be exposing yourself to more risk, but just ensure everything is fused correctly and you should be OK. If you're not competent with high voltage then don't do it. I'd be interested to hear your specific concerns about the fire risks.

boony
boony

"entirely liable for the disaster" trans: "I like to approach everything with a solid amount of fear and a humorless attitude." "Frankly, my time is more valuable" Like spending countless, fun-filled hours writing cranky, sour posts?

sMoRTy71
sMoRTy71

Aren't you just a ray of sunshine. Not sure how this is a firetrap considering that all of the wires are soldered securely and all wires are thoroughly wrapped with electrical tape.

sMoRTy71
sMoRTy71

May be a little advanced for me, though :)

MetalFR0
MetalFR0

As a newbie to this kind of DIY work, how would you incorporate a fuse into that design?

Larry the Security Guy
Larry the Security Guy

Depending on your cooling needs, convection cooling might be enough. Use rigid or smooth-wall ducting to cut down on interference and cleaning requirements. Route the duct up and out of the room, but not to the outside without some environmental and pest control. Incoming air should use a vent and not your DVD slot - install intake vents and use filters to reduce dust buildup. The vents should be directly opposite the exhaust; intakes at the lower front or on the bottom, exhaust at the upper rear or on the top. If convection isn't enough, attach a blower or fan on the far end of the exhaust so it draws air out. Being out of your media room will keep noise to a minimum. If your exhaust goes outside, you'll want to use a fan or blower rated for outdoor service, or provide a weather-proof enclosure. Blowers are more efficient than fans and are generally quieter CFM for CFM. But small blowers are noisy, and large blowers might move too much air. Moving too much air will create noise at your intake vents and draw air in through every opening, including your DVD slot.

cparris
cparris

There are several things to consider when you duct a fan. When placing a fan in a duct it inherently decreases the CFM rating of the fan due to the friction of the duct on air. For this reason it would acceptable to say that a 92mm fan that is ducted will give you the same performance as an 80mm fan that is not ducted. Bends in the duct also affect the air flow by increasing friction and also changing the inertia of the air. The size of the duct also affects the air flow. For example a larger duct on a smaller fan can cause a very small impact on the performance of that fan. A larger fan than the duct will cause greater efficiency losses and more noise. Ducts also have a resonant frequency and often have multiple frequencies. Like the port in a speaker enclosure, it can possibly amplify some noise from inside the enclosure. Finally if you want to push your air through the duct rather than pull it, have a small area to work with, and need high air flow, then a blower is a better choice than a regular fan. Blowers should be a last resort simply because they are really noisy at higher speeds and at most speeds. For those of you with slim line servers it can and often is that loud for the small ones. However, they have a very high static pressure they can support in comparison to a regular fan making them ideal for high flow and small space. For the 120v fans; you can check on eBay for rack cooling fans in the professional audio equipment section.

NICKK
NICKK

I used to use a either multiple 3" or 4" (i can't remember, sorry) 120V AC powered fans on the back of my case that used the flexible dryer exhaust tube attached from the fan (it BARELY squeezed over the fan) and on the other side I placed it over passively cooled heatsinks. This was back in the day of Pentium II's etc. I used one on the CPU and OC'd it 50%+ and one on the video card and again OC'd the crud out of it. This worked very, very well for many years. -Nick

acmp
acmp

Simply get a fuse holder and suitable fuse from your parts shop and add it to the +ve wire near to the power supply. For most of this type of stuff a 1Amp 230/110V fuse will do as you are really only interested in stopping a short circuit.

MetalFR0
MetalFR0

Thanks - if I ever do this w/ some fans I'll have to look into that.

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