Cooling a TV

Control: management of fans, temp/rpm monitoring via soft/hardware

Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee

markjia
Posts: 171
Joined: Sat Apr 24, 2004 4:31 pm
Location: Vancouver BC

Cooling a TV

Post by markjia » Sun Nov 07, 2004 9:06 pm

I'm installing a TV into a wall and am concerned with it overheating in the tight space, so I have bought two 92mm Panaflo L1As to aid in the cooling. I need something to power them though.

I'm thinking of using an extra universal AD/DC tranformer to power each of the two fans at maybe 6V or 7.5V (the tranformer only does multiples of 1.5V). The tranformer can handle 300mA, and I was wondering it one tranformer would be sufficient for both fans.

markjia
Posts: 171
Joined: Sat Apr 24, 2004 4:31 pm
Location: Vancouver BC

Post by markjia » Sun Nov 07, 2004 9:33 pm

Also, about the placement of the fans...

The TV has it's own fans pumping air out of the sides (it's a 42" LCD projection TV). I am thinking of mounting the fans under the openning on the sides (located near the base of the TV) and pumping air up. The TV will be pretty tightly sealed, and there is more room vertically that horizontally.

Another option could be to mount the fans on top of the opennings and pull air up. But, I'm thinking that fans push air in a more concentrated manner than pulling (at least in an open environment), so pushing the air across the vents would be more effective.

ONEshot
Posts: 257
Joined: Sun Jan 11, 2004 11:37 pm

Post by ONEshot » Sun Nov 07, 2004 9:37 pm

Whoa whoa whoa, fans are a BAD idea in a TV. The reason that TV manufacturers dont put in fans is because they will blow dust where its not needed. And unlike in computers, dust on the TV circuitry WILL fuck things up.

DO not recommend it, bud.

markjia
Posts: 171
Joined: Sat Apr 24, 2004 4:31 pm
Location: Vancouver BC

Post by markjia » Sun Nov 07, 2004 10:01 pm

There are already two fans in there tha pump air out. They also operate for a couple minutes after you turn the TV off.

I am also not going to mount the new ones inside, but rather strap them perpendicularly on the sides (the sides are actually diagonal, so you mount be able to see them.

I'm not suppose to put the TV is such a cramped space, so I need to do something to accomidate the situation.
Last edited by markjia on Sun Nov 07, 2004 10:03 pm, edited 1 time in total.

Rusty075
SPCR Reviewer
Posts: 4000
Joined: Sun Aug 11, 2002 3:26 pm
Location: Phoenix, AZ
Contact:

Post by Rusty075 » Sun Nov 07, 2004 10:01 pm

Read your TV's manual. It will list required side, back, and top clearances. Keep to those, and natural convection will be enough to keep it cool.
[size=75][b]Senior Contributing Writer, SPCR[/b][/size]

markjia
Posts: 171
Joined: Sat Apr 24, 2004 4:31 pm
Location: Vancouver BC

Post by markjia » Sun Nov 07, 2004 10:04 pm

It list 4" behind it. I can't accomidate that. Plus, I've already begun cutting a hole out of my wall...there is no going back anymore ;)

lenny
Patron of SPCR
Posts: 1642
Joined: Wed May 28, 2003 10:50 am
Location: Somewhere out there

Re: Cooling a TV

Post by lenny » Sun Nov 07, 2004 10:32 pm

markjia wrote:I'm thinking of using an extra universal AD/DC tranformer to power each of the two fans at maybe 6V or 7.5V (the tranformer only does multiples of 1.5V). The tranformer can handle 300mA, and I was wondering it one tranformer would be sufficient for both fans.
According to this, at 12V the FBA09A12L draws 110 mW. At 6 - 7.5V it should draw less than that amount, so 300mA should be safe.

I'd be more concerned about airflow though. Two 92mm Panaflo L undervolted is not going to be delivering a lot of air.

Already cutting into your wall? Well, you're definitely braver than I am :-)

markjia
Posts: 171
Joined: Sat Apr 24, 2004 4:31 pm
Location: Vancouver BC

Post by markjia » Mon Nov 08, 2004 9:36 am

Thanks for the information.

As for the issue with dust, if I install the fans above the opennings (to pull air up), will that help minimize dust?

What about angling the fans to blow diagonally?

markjia
Posts: 171
Joined: Sat Apr 24, 2004 4:31 pm
Location: Vancouver BC

Post by markjia » Mon Nov 08, 2004 4:23 pm

To clarify my idea, here are a couple sketches to illustrate the designs I've come up with:

Code: Select all

|->
|->
|->
|->
|->
|->
|->  ^
|-> / ^
    \/ ^
     \/ ^
      \/


     ^
    / ^
|-> \/ ^
|->  \/ ^
|->   \/
|->
|->
|->
|->
|->


|->
|->
|->
|->
|->
|->^^^^
|->||||
|->----


   ^^^^
   ||||
|->----
|->
|->
|->
|->
|->
|->
|->
these are fans (with the arrow like characters being the direction or air):

Code: Select all

^^^^
||||
----

and

     ^
    / ^
    \/ ^
     \/ ^
      \/

and this is the openning in the TV (that has a fan blowing air out of):

Code: Select all

|->
|->
|->
|->
|->
|->
|->
|->
Which of these (or any other design) would be the most effective at keeping dust out?

Thanks

Straker
Posts: 657
Joined: Fri Jul 23, 2004 11:10 pm
Location: AB, Canada
Contact:

Post by Straker » Mon Nov 08, 2004 9:56 pm

dust in tvs will fuck them up?

how many people do you know that have EVER cleaned the inside of their tv? heh.
somehow, they don't collect very much dust anyways. had to open up one of mine that's about 9 years old and has had probably several pounds of dust removed from the outside of it, and there wasn't enough on the inside to be worth cleaning properly.

what exactly is on the other side of the wall, any chance you could just ventilate it through that? the way you're doing it it seems like it'd be best just getting air flowing through the area instead of actually into the tv.

markjia
Posts: 171
Joined: Sat Apr 24, 2004 4:31 pm
Location: Vancouver BC

Post by markjia » Mon Nov 08, 2004 10:27 pm

The TV is 4 feet wide (and 4 ft tall including the stand). The openning I've made is about 5' wide and there is about 2" clearance behind and 2" on top. The manual says that the TV should have 4" clearance behind, and that if placed in a confined space like I'm doing, there should be proper ventilation.

Behind the TV is a small hallway. I'm thinking about making some opennings, but I'd have to give them some design to be asthetically pleasing. Plus, I don't have a router (at least not yet).

lenny
Patron of SPCR
Posts: 1642
Joined: Wed May 28, 2003 10:50 am
Location: Somewhere out there

Post by lenny » Tue Nov 09, 2004 12:47 am

How about opening some holes near the floor on the wall in the hallway, and covering it with heat registers?

andywww
Posts: 85
Joined: Sun Aug 29, 2004 8:54 pm
Location: Palo Alto

Post by andywww » Tue Nov 09, 2004 9:18 am

perhaps if you placed fans so that they circulated air in the space behind the tv it would qualify as adequate ventilation and compensate for the reduced clearance?
[size=75]P4 3.06 + Zalman 7000AlCuA, ATI Radeon 9600, SST 350, Seagate 7200.7 80gb & 120gb, 2x 120mm Orange Yate Loon, SLK3000B[/size]

Putz
Posts: 368
Joined: Thu Aug 21, 2003 1:25 am
Location: Ottawa, Canada
Contact:

Post by Putz » Tue Nov 09, 2004 9:36 am

Get a plasma. Problem solved :)

Seriously, though, I would put one or two 120mm fans at the top, sucking air out. This would be a good application for the 38-mm-thick Panaflo L1As. Then undervolt them until you're satisfied. At 6V (if they start reliably), that would probably be enough circulation.

ferdb
Posts: 124
Joined: Fri Sep 10, 2004 1:13 pm
Location: austin, TX

Post by ferdb » Tue Nov 09, 2004 11:55 am

You can also use Sunon 2123XST 120x38mm 230V ac fans and run them on 120v. Then you don't need a power supply. If they are too noisy even undervolted at 120V put a 270 ohm 3 watt power resistor in series with each fan. These things are exceptionally quiet. The fans are $9 from Allied electronics. Allied also sell a 1000 ohm 3Watt potentiometer for $5 (EUP1400 1K, Stock number 522-0049) that you can put in series with the 2123XST fan to allow you to control the fan speed down to the subaudible range if you want more control than just using a fixed 270 ohm resistor. You will need 1 pot per fan, Don't stick two fans on one pot or you will exceed the dissapation limits of the pot.
If the 2123XST doesn't provide enough airflow at 120V for your application (unlikely) you can put a 4.7uF Capacitor in series with it. This will boost the voltage across the fan to about 160Vac and speed it up considerably. You can still use the pot in series with it to control the speed if you want, but the minimum fan speed will now be greater. Allied electronics has an appropriate capacitor (stock number 613-0500) for $2.11 . You will need one capacitor for each fan.
The Sunon fans are stock number 997-2123
Fan cords are stock number 609-5642 for a 3' cord

silvervarg
Posts: 1283
Joined: Wed Sep 03, 2003 1:35 am
Location: Sweden, Linkoping

Post by silvervarg » Wed Nov 10, 2004 1:03 am

Putz:
Get a plasma. Problem solved
He has already got an LCD-TV, and plasmas generate a lot more heat than LCD-TV, so that would make things much worse.

A single transformer should work fine.
Have you considered to try to connect both fans in series?
E.g. transformer on 12V gives 6V per fan. This will make the transformer a lot happier and it will produce a lot less heat.
[size=75][b]Passive XP2500+:[/b] Convection cooled, ~XP1500+, DP-102 cooler, Abit NF7-M, CNPS6000Cu on NB, Antec Overture, Samsung P80 120GB[/size]

sthayashi
*Lifetime Patron*
Posts: 3214
Joined: Wed Nov 12, 2003 10:06 am
Location: Pittsburgh, PA

Post by sthayashi » Wed Nov 10, 2004 5:42 am

silvervarg wrote:He has already got an LCD-TV, and plasmas generate a lot more heat than LCD-TV, so that would make things much worse.
Even if it's a projection TV? There's a big difference in price and size.
[size=75][url=http://www.twolf1300.net/sthayashi/SPCR/systems.html]My Power Rig, Storage Rig, HTPC and Main Rig[/url][/size]

markjia
Posts: 171
Joined: Sat Apr 24, 2004 4:31 pm
Location: Vancouver BC

Post by markjia » Wed Nov 10, 2004 9:54 am

Connecting the fans in series? Hum...perhaps...I don't know enough about transformers to have a proper understanding of which is better.

The only thing with connecting the fans in series is that if one dies, then the other could also stop. Although, I guess if when the fan dies, it still lets current pass, then I would have a warning that one fan is gone (as the other will become louder).

Putz
Posts: 368
Joined: Thu Aug 21, 2003 1:25 am
Location: Ottawa, Canada
Contact:

Post by Putz » Wed Nov 10, 2004 10:14 am

silverarg wrote:He has already got an LCD-TV, and plasmas generate a lot more heat than LCD-TV, so that would make things much worse.
But...
markjia wrote:it's a 42" LCD projection TV
... so I think that my only-semi-serious remark still holds minor value.


Those AC-DC transformers will only produce negligible heat compared to a television, so I think that it wouldn't be a bad way to go. It would be a quick 'n easy solution, while still allowing good flexibility (and choice in fans, no less).

markjia
Posts: 171
Joined: Sat Apr 24, 2004 4:31 pm
Location: Vancouver BC

Post by markjia » Wed Nov 10, 2004 5:17 pm

I have another idea to duct the fans to pull the air coming out of the exhausts to flow under the TV and through the opennings in the stand. Now, I cannot actually have the duct run clear of the stand as they would become visible and unsightly. Instead, I can take advantage of the fact the the stands are quite short (maybe 18" high) and below eye level, so if the duct is at the back, you can't actually see it while sitting. The the air would be pushed out along side the other components (like DVD player, etc).

But since the duct does not completely clear the stand, the air will potentially heat up the other components slightly (it's realizely open still)...could this be a concern?

Plus, the area is somewhat open (esp compared to a computer case), so the duct would not be terribly efficient.

Should I even bother ducting the fans? Actually, is it even worthwhile to use fans? Some people sound apposed to the idea, and I know it's not convernsional, but given that I have limited ventilation, are there any better options?

ferdb
Posts: 124
Joined: Fri Sep 10, 2004 1:13 pm
Location: austin, TX

Post by ferdb » Wed Nov 10, 2004 6:01 pm

Try it without fans and stick a thermometer back there and see how hot it gets on the top of the TV. If it doesn't get too hot you don't need fans.

ddrueding1
Posts: 419
Joined: Sun Sep 19, 2004 1:05 pm
Location: Palo Alto, CA

Post by ddrueding1 » Wed Nov 10, 2004 6:23 pm

ferdb wrote:Try it without fans and stick a thermometer back there and see how hot it gets on the top of the TV. If it doesn't get too hot you don't need fans.
Seconded. I think they're likely a bit paranoid about such things. You may also want to just install a vent below and above the TV, convection should work well depending on the ambient temp...
[size=75]A64 6000+, GF 7950GT, 4GB DDR2-1000, Gigabyte GA-M57SLI-S4, Auzentech X-Plosion 7.1, 3Ware 9650SE-16ML, 2x 74GB Raptors, 6x 750GB 7200.10s, Antec Nine Hundred, Samsung SATA DVD-RW, Seasonic M12 700W, Logitech G15, Razor Copperhead, Vista Ultimate[/size]

Straker
Posts: 657
Joined: Fri Jul 23, 2004 11:10 pm
Location: AB, Canada
Contact:

Post by Straker » Wed Nov 10, 2004 6:55 pm

yeah. look how crappy ventilation is around most appliances and none ever seem to have problems because of it. i don't think i've ever seen a fridge with more than an inch of space around the sides/top. :)
of course TVs are different, but not like it's a huge CRT.

silvervarg
Posts: 1283
Joined: Wed Sep 03, 2003 1:35 am
Location: Sweden, Linkoping

Post by silvervarg » Thu Nov 11, 2004 12:08 am

i don't think i've ever seen a fridge with more than an inch of space around the sides/top
You do have a point here, but we should be carefull to draw comparisons too far. A typical fridge is quite big, so making it a few inches bigger will not make consumers upset. It is normal that the fridge has about 4 inch clearance in the sockle under it with unrestrictive air intake and at least 2 inch of space on the back. Both these spaces are typically considered to be inside the fridge. So even with almost no space outside the fridge it still has quite a lot of free air space.

On a flat TV the manufacturer don't want to make the TV 2 inches thicker since it would not look as good, so chances are that they didn't put much extra space inside the chassi.
If you are lucky you could see if there is space through the vent holes.
If you are ready to void your warranty you could probably do some mods, like making the intake and exhaust slots less restrictive, much like like mods we do on computers. On the other hand it does not sound tempting to void the warranty on a brand new large TV...
[size=75][b]Passive XP2500+:[/b] Convection cooled, ~XP1500+, DP-102 cooler, Abit NF7-M, CNPS6000Cu on NB, Antec Overture, Samsung P80 120GB[/size]

sthayashi
*Lifetime Patron*
Posts: 3214
Joined: Wed Nov 12, 2003 10:06 am
Location: Pittsburgh, PA

Post by sthayashi » Thu Nov 11, 2004 8:24 am

silvervarg wrote:On a flat TV the manufacturer don't want to make the TV 2 inches thicker since it would not look as good, so chances are that they didn't put much extra space inside the chassi.
Once again, this is a rear projection screen TV, not a flat panel TV. They have all the space they need. Newer RPTVs are a lot thinner than the old box-like ones, but they're still pretty thick (7-12" thick was what I heard, as opposed to the 2-3" of true flat panel displays).

The flipside/counter argument here is that if RPTVs are at all like normal LCD projectors, there's a fairly powerful bulb inside that requires cooling. I'm not entirely sure since I've largely ignored LCD RPTVs.
[size=75][url=http://www.twolf1300.net/sthayashi/SPCR/systems.html]My Power Rig, Storage Rig, HTPC and Main Rig[/url][/size]

lenny
Patron of SPCR
Posts: 1642
Joined: Wed May 28, 2003 10:50 am
Location: Somewhere out there

Post by lenny » Thu Nov 11, 2004 9:50 am

ddrueding1 wrote:You may also want to just install a vent below and above the TV, convection should work well depending on the ambient temp...
Thats why I suggested an opening on the other side of the wall (in the hallway) near the floor, covered with heat register, for cool air intake.

markjia
Posts: 171
Joined: Sat Apr 24, 2004 4:31 pm
Location: Vancouver BC

Post by markjia » Thu Nov 11, 2004 11:32 pm

This is the actual TV (sort of, I have last year's model, but they are very similar).

I can't find any specifications as to the maximun allowed ambient temperature though.

I'm considering either making vents at the top of the frame, or putting two fans at the top. The latter is easier, but which is more effective?

sthayashi
*Lifetime Patron*
Posts: 3214
Joined: Wed Nov 12, 2003 10:06 am
Location: Pittsburgh, PA

Post by sthayashi » Thu Nov 11, 2004 11:55 pm

Your TV's lamp is rated for 100W and total power consumption during usage is 230W. I'm sorry that I have no clue as to how to help you, but I want to say that those two pieces of information are important and relevent in your case.
[size=75][url=http://www.twolf1300.net/sthayashi/SPCR/systems.html]My Power Rig, Storage Rig, HTPC and Main Rig[/url][/size]

burcakb
Posts: 1443
Joined: Tue Mar 09, 2004 9:05 am
Location: Turkey

Post by burcakb » Fri Nov 12, 2004 1:15 am

Please please please, remember this is an LCD PROJECTION TV.

That technology works by projecting POWERFUL light onto a SMALL LCD panel at VERY CLOSE RANGE. The technology is very similar to a portable projector and I'm sure you all know how hot those things can get.

This is a case where "you can get by with a little more heat" WILL NOT WORK. The LCD is very sensitive to heat and improper ventilation will severely shorten the life of the LCD panel. Since those panels are also installed in a vacuum tube, changing with a new one is usually not possible.

AFAIK that TV is about twice as thick as a pure LCD/Plasma display. I strongly suggest you stick to the manufacturers' clearence specs.
[size=75][url=http://forums.silentpcreview.com/viewtopic.php?t=17474]Thor's Hammer[/url]
Loki's Magic: Coming soon...
[url=http://forums.silentpcreview.com/viewtopic.php?t=19771]Odin's Chariot[/url][/size]

silvervarg
Posts: 1283
Joined: Wed Sep 03, 2003 1:35 am
Location: Sweden, Linkoping

Post by silvervarg » Fri Nov 12, 2004 2:00 am

AFAIK that TV is about twice as thick as a pure LCD/Plasma display. I strongly suggest you stick to the manufacturers' clearence specs.
Here is the size from the links above.
Dimensions (WxHxD)
47 3/8" x 32 1/4" x 14 5/8" (1201x 819 x 371 mm)

Thats quite a lot compared to a pure LCD.
Unfortunately he has allready mentioned that it is not possible to stick to the manufacturers clearence specs. A wall simply has a certain thickness, not much you can do about it...

The idea with air intake close to the floor (preferably on the other side of the wall) and exhaust near the roof is a good idea. If this is done in combination with the fans I think you should do fine.
Fans will make sure we have a lot of extra airflow around the really hot parts, and the long distance between intake and exhaust should create a fairly effective chimney that makes sure the air wount heat up too much if the TV is running for many hours straight.
[size=75][b]Passive XP2500+:[/b] Convection cooled, ~XP1500+, DP-102 cooler, Abit NF7-M, CNPS6000Cu on NB, Antec Overture, Samsung P80 120GB[/size]

Post Reply