Is there a use for Peltiers in Silent computing?

[Kremmit]

I've been playing with an idea for using a Peltier with two heatsinks, as a few have suggested above. The twist I want to build the whole rig into a sort of "chimney", letting the hot air's natural tendency to rise in concert with the cold air's natural tendency to fall in an attempt to create some free, fanless airflow. The hot side of the peltier sits at the very top of the chimney, adding extra heat to the air after it's already passed over all the pc components, because hotter air will rise faster. Meanwhile, the cold side of the peltier sits at the top of an intake duct, cooling the incoming air as it passes, and that cooled air naturally falling. The hope is that the free, silent, cooled airflow this creates can eliminate one, two, or more of the traditional fans, if the rest of the system is designed properly. In case my description is hard to follow, I'm attaching a quick drawing I just did. Nothing is to scale, this is just to illustrate the concept. No fair laughing at my drawing/handwriting, either.



The problem I'm struggling with is, you can't use any kind of heatpipe on the cold side, since the thing that makes heatpipes work is a heat source boiling the liquid inside. That certainly won't be happening on the cold side! So, plain fins on the cold side, but what I'm wondering is, is is still a good idea to use heatpipes on the hot side? Is it a problem with peltiers if the heat/cool dissapation is out of balance?

Of course, it's all academic right now for me; I haven't got the funds or the time to tackle a project like this any time soon. Besides, I'm still fiddling with my P180 project. But it's a fun concept to play around with.

[cyberspyder]

Fundamentally, Peltiers are notoriously inefficient. This is where undervolting and 320W Pelts come in. When the Pelt is running at half the voltage (or 3/4, just not 100%), efficiency shoots right up. That's also why you don't put heatsinks on Pelts. Most HSF are not designed to cool more than 140W, thus watercooling is a must. The lower powered pelts (80W, 40W) will be compatible, although in reality, you won't be running it at 100% and undervolting it will result in a loss of cooling power. That's why you get a higher powered one, such as the 226W or 320W. Also, most PSUs can't handle the added current of a Pelt, so you'll need an Aux. PSU, such as this Meanwell.

References:
http://www.xtremesystems.org/forums/sho ... hp?t=38367
http://www.xtremesystems.org/forums/sho ... hp?t=67927

Undervolting guide (from Bloody_Sorcerer at XS):

80 watt / 16.1 VMax / 8.0 IMax
5 volts: 5.7 watts; 2.48 amps
6 volts: 8.9 watts; 2.98 amps
7 volts: 12.8 watts; 3.47 amps
8 volts: 17.4 watts; 3.97 amps
9 volts: 22.8 watts; 4.47 amps
10 volts: 28.8 watts; 4.96 amps
11 volts: 35.6 watts; 5.46 amps
12 volts: 43.0 watts; 5.96 amps
13 volts: 51.2 watts; 6.45 amps
14 volts: 60.1 watts; 6.95 amps
15 volts: 69.7 watts; 7.45 amps
16 volts: 80 watts; 7.95 amps

120 watts / 24.6 VMax / 7.9 IMax
5 volts: 3.5 watts; 1.60 amps
6 volts: 5.5 watts; 1.92 amps
7 volts: 8.0 watts; 2.24 amps
8 volts: 10.8 watts; 2.56 amps
9 volts: 14.1 watts; 2.89 amps
10 volts: 17.9 watts; 3.21 amps
11 volts: 22.1 watts; 3.53 amps
12 volts: 26.7 watts; 3.85 amps
13 volts: 31.0 watts; 4.17 amps
14 volts: 36.4 watts; 4.49 amps
15 volts: 42.2 watts; 4.81 amps
16 volts: 48.5 watts; 5.13 amps
17 volts: 55.2 watts; 5.45 amps
18 volts: 62.3 watts; 5.78 amps
19 volts: 69.8 watts; 6.1 amps
20 volts: 77.8 watts; 6.42 amps
21 volts: 86.2 watts; 6.74 amps
22 volts: 95.0 watts; 7.06 amps
23 volts: 104.3 watts; 7.38 amps
24 volts: 114.0 watts; 7.70 amps

169 watt / 16.4 VMax / 16.1 IMax
5 volts: 15.7 watts; 4.90 amps
6 volts: 22.6 watts; 5.89 amps
7 volts: 30.8 watts; 6.87 amps
8 volts: 40.2 watts; 7.85 amps
9 volts: 50.9 watts; 8.83 amps
10 volts: 62.8 watts; 9.81 amps
11 volts: 76.0 watts; 10.79 amps
12 volts: 90.5 watts; 11.78 amps
13 volts: 106.2 watts; 12.76 amps
14 volts: 123.2 watts; 13.74 amps
15 volts: 141.4 watts; 14.72 amps
16 volts: 160.9 watts; 15.70 amps

172 watt / 24.6 VMax / 11.3 IMax (got the numbers from silverprop)
5 volts: 7.1 watts; 2.3 amps
6 volts: 10.2 watts; 2.8 amps
7 volts: 13.9 watts; 3.2 amps
8 volts: 18.2 watts; 3.7 amps
9 volts: 23.0 watts; 4.1 amps
10 volts: 28.4 watts; 4.6 amps
11 volts: 34.4 watts; 5.1 amps
12 volts: 40.9 watts; 5.5 amps
13 volts: 48.0 watts; 6.0 amps
14 volts: 55.7 watts; 6.4 amps
15 volts: 64.0 watts; 6.9 amps
16 volts: 72.8 watts; 7.3 amps
17 volts: 82.1 watts; 7.8 amps
18 volts: 92.1 watts; 8.3 amps
19 volts: 102.6 watts; 8.7 amps
20 volts: 113.7 watts; 9.2 amps
21 volts: 125.3 watts; 9.6 amps
22 volts: 137.6 watts; 10.1 amps
23 volts: 150.4 watts; 10.6 amps
24 volts: 163.7 watts; 11.0 amps

226 watt / 15.2 VMax / 24 IMax
5 volts: 24.5 watts; 7.89 amps
6 volts: 35.2 watts; 9.47 amps
7 volts: 47.9 watts; 11.05 amps
8 volts: 62.6 watts; 12.63 amps
9 volts: 79.2 watts; 14.21 amps
10 volts: 97.8 watts; 15.78 amps
11 volts: 118.4 watts; 17.36 amps
12 volts: 140.9 watts; 18.94 amps
13 volts: 165.3 watts; 20.52 amps
14 volts: 191.7 watts; 22.10 amps
15 volts: 220.1 watts; 23.68 amps

320 watt / 14 VMax / 26 IMax (these numbers were given to me by NoL, so if they're wrong, yell at him, not me)
5 volts: 40.8 watts; 9.3 amps
6 volts: 58.7 watts; 11.1 amps
7 volts: 80 watts; 13 amps
8 volts: 104.5 watts; 14.9 amps
9 volts: 132.2 watts; 16.7 amps
10 volts: 163.3 watts; 18.6 amps
11 volts: 197.6 watts; 20.4 amps
12 volts: 235.1 watts; 22.3 amps
13 volts: 275.9 watts; 24.1 amps
14 volts: 320 watts; 26 amps

OK, now, because wintsch labs gives conflicting information on this bad boy, theres 2 charts. I don't know which one is right, because wintsch labs is wierd. Here's the 32.8 IMax one; the second is the 25 IMax one.
437 watt / 26.7 VMax / 32.8 IMax
5 volts: 15.3 watts; 6.14 amps
6 volts: 22.1 watts; 7.37 amps
7 volts: 30.0 watts; 8.59 amps
8 volts: 39.2 watts; 9.82 amps
9 volts: 49.7 watts; 11.05 amps
10 volts: 61.3 watts; 12.28 amps
11 volts: 74.2 watts; 13.51 amps
12 volts: 88.3 watts; 14.74 amps
13 volts: 103.6 watts; 15.97 amps
14 volts: 120.2 watts; 17.19 amps
15 volts: 137.9 watts; 18.42 amps
16 volts: 156.9 watts; 19.65 amps
17 volts: 177.2 watts; 20.88 amps
18 volts: 198.6 watts; 22.11 amps
19 volts: 221.3 watts; 23.34 amps
20 volts: 245.2 watts; 24.56 amps
21 volts: 270.3 watts; 25.79 amps
22 volts: 296.7 watts; 27.02 amps
23 volts: 324.3 watts; 28.25 amps
24 volts: 353.1 watts; 29.48 amps
25 volts: 383.1 watts; 30.71 amps
26 volts: 414.4 watts; 31.94 amps

437 watt / 24 VMax / 25 IMax
5 volts: 19.0 watts; 5.2 amps
6 volts: 27.3 watts; 6.2 amps
7 volts: 37.2 watts; 7.3 amps
8 volts: 48.6 watts; 8.3 amps
9 volts: 61.5 watts; 9.4 amps
10 volts: 75.9 watts; 10.4 amps
11 volts: 91.8 watts; 11.5 amps
12 volts: 109.3 watts; 12.5 amps
13 volts: 128.2 watts; 13.5 amps
14 volts: 148.7 watts; 14.6 amps
15 volts: 170.7 watts; 15.6 amps
16 volts: 194.2 watts; 16.7 amps
17 volts: 219.3 watts; 17.7 amps
18 volts: 245.8 watts; 18.8 amps
19 volts: 273.9 watts; 19.8 amps
20 volts: 303.5 watts; 20.8 amps
21 volts: 334.6 watts; 21.9 amps
22 volts: 367.2 watts; 22.9 amps
23 volts: 401.3 watts; 24.0 amps
24 volts: 437 watts; 25 amps

Brendan

[JaRoD]

One way to use a peltier that I've thought about is to put one on the backside of the motherboard right behind the cpu. And then use some plate so it makes contact with the side of the case. Running at 5v the peltier should be able to atleast shave a few degrees off the cpu while being completely silent. I'd try it myself but I don't feel like cutting up my new case

I did try putting a peltier at 5v on the backside of the graphics card and I used a 50*50*25mm heatsink. Since there are small components on right behind the gpu I used blutack to make contact I managed to shave off 2 degrees of the gpu temp. The heatsink was maybe 40c so with a larger one it would probably improve maybe 2c more but since I have a zalman vf900 on the card there wasn't any room for a larger heatsink. And peltiers need to be squeezed hard against the heatsinks to work really well and I had only the thermal paste to keep it there.

It was a 80w 16v peltier and it used about 5-10w of power running at 5v.

[SoopahMan]

SoopahMan - yes you can use it to generate electricity but what for? ... peltiers can be used as a voltage source like batteries, but here we are solely interested in cooling right?

For keeping things cool! If the electricity that comes out is fed back into the system to power it, then you reduce the demand back at the Power Supply because some of the electricity normally drawn from the wall is now being fed by upconverted heat at the Peltier. Less draw at the PSU means less heat created from the PSU converting AC to DC, means less heat in the system.

So yes, the goal is a cool system, but the REAL goal is to avoid creating heat in the first place. Displacing some of the electrical source to inside the system does just that.

[Terje]

One thought I have been playing with is to use water cooling to lead the heat out of the cabinet and then put the peltier on the outside to cool the water.

Think a reserator sized heatsink put on a peltier cooling the water.

Terje

[Aris]

One thought I have been playing with is to use water cooling to lead the heat out of the cabinet and then put the peltier on the outside to cool the water.

Think a reserator sized heatsink put on a peltier cooling the water.

Terje

there called "water chillers", and you can just buy them, but yes this is basically how they work.