Peltier Cooling system

[troubleMakr]

I have read some stuff about TEC (Peltier effect) devices, and there seems to be a bit of misunderstanding about TEC's and the Peltier effect in general. This is basic thermodynamics, but saying that it "pumps" heat to one side of the device, or "pumps cool" to the other side is a gross misrepresentation. The Peltier effect utilizes the the fact that heating effect of electrical current (something we all know about, hence the need for cooling systems) is different for materials with different levels of conductivity. The difference in heat, on an atomic level, is just a different amount of thermal vibration (atoms/molecules moving, or K_t). What a TEC does is create low K_t on one side and high K_t on the other side of a compact semiconducting circuit.
To get to the point of my gripe, blowing the cooled air off of the side of the Peltier, through a duct (the way that most ppl I have heard do it) to the hot parts (CPU, video card, etc) is inefficient. I feel, thermodynamically, that it would make much more sense to simply suck the hot air around your CPU onto the cool side of the TEC via a fan.
So it would go something like this - processor, heatsink(thermal pasted onto processor), fan (blowing towards peltier), brackets, peltier, heatsink (thermal pasted onto hot side of peltier), fan. Go here to a site I quickly created when I found out that this site doesnt accept bitmaps
This, while being more efficient in theory, will also eliminate/reduce the potential problem of blowing the moist air that is often created by TEC's when they operate. By keeping the heat from your processor onto the cold side of the TEC, the TEC's operational efficiency is increased, the low K_t air around the cold side is constantly exposed to the high K_t air pulled off the processor by the fan, cooling down the processor, and the case as a whole. The device I show on the linked site would be best placed directly perpendicular to a side case fan, so the heat exhaust fan of the TEC cooling stack will put out right into a case exhaust fan, or perhaps, cut your own case hole, and make the TEC stack longer through the use of bigger (taller) heatsinks and fans.
This will be very stable if constructed right, attached to the cpu heatsink clip, and to the other side of the case.

 

[Thelemac]

First off, I'm not quite sure how it is that sucking the air from your hsf and blowing it onto the cold side of the tec is going to cool your processer any. It seem that it would just serve to warm the cold side up a bit.

Secondly, where are you getting the ducting that people use for thier tecs? Most people that I see are using watercooling to cool those things.

I guess, really, I'm not getting your point, or where you're even coming up with the misconception that others have. By sticking that tec in the middle of nowhere cooling some air you're just losing most of it potential (air is a nice insulator, really) as direct contact is going to cool much better. Also, when people refer to pumping heat, its really just a euphamism for what it does...ultimatley moving the heat from the cpu to outside the case.

 

[ken257]

Sorry dude I took a look at your picture of the setup and I don't get why you would ever want to do that, doesn't even make sence. If you want to cool the air inside your case you would need a heatsink and a fan on the outside of the case to cool the hot side of the tec with a second heatsink and fan inside the case. This sink will be chilled by the cold side of the tec and the fan on it will aid in transfering the cold to the inside of the case.

The downside is that you would need some serious tec's to keep up with the heat generated by the computer. Good case ventalation or a watercooled tec on the cpu are much better and more practical solutions.

 

[troubleMakr]

gaah, correct correct correct.
I was thinking bassackwards - the fan should blow from the cool side TEC onto the hetsink. sorry about that.....*sheepish grin*

 

[ken257]

It doesn't matter how long any of us have been here or what are acomplishments are, we all have a lot to learn and this is a great place to do it!

 

[LimeyGreg]

I just read an article somewhere where a guy took two "flower" heatsinks, one aluminum and one copper and he clamped them onto a big peltier. Then he built a Plexiglass box around it with a partition separating the two heatsinks.

The idea was to have the cold sink inside the case, through the side panel and circulate the air inside the computer through the cold heatsink. The hot heatsink stayed outside the case and he blew air through it to remove the heat. I'll see if I can find the link.

If you could seal the case then dust and condensation would not be such a concern any longer. It would probably be best to duct outside air to the psu directly though. I think he was mainly trying to alleviate the condensation problem when cooling the CPU directly.

I just found the link, here it is http://myhome.netsgo.com/wesleycrushr/Hardware/gui010604a-1.htm
Reading it more closely, he only supplied the intake fan of his comp with cool air, I think fitting it into the case would have been a more effective solution.