An idea for using a TEC differently.....

[lapoltba]

I had a thought about using TEC or peltier... whatever you want to call them.... a litttle differntly than most people use them.

Usually they are put directly on the processor in order to keep it as cold as possible. The major problem with this is obviously condensation.

Here is my thought.... In order to eliminate the problem with condensation and use a standard heatsink/waterblock, why not use the TEC to chill the water to near or below ambient temperature. then just use a simple fan/ heatsink to cool the peltier?

Control for the TEC would have to include an ambient temperature sensor, a water temp sensor, and a CPU temp sensor. Basically the water would be cooled by the TEC to the point where it will not cause condensation at the processor.

I am planning on using the CrystalFontz 635 with the SCAB fan controller and the software would make it stupid easy to integrate. Super accurate temp sensors for the water, and ambient temperature, as well as the possibility to integrate a "one wire" humidity sensor to make the control perfect. (using humidity and ambient temperature you can caluclate dewpoint, the temperature at which condensation will form)

Anyone have any experience with this, or seen it done?

-Brian

 

[Zero82z]

That's called a water chiller, and it's been done before . A lot of people use phase-change to cool down the water, but I've seen TECs used as well.

The problem is that it's still a careful balance to get the water to the right temperature, since sub-ambient water can cause condensation to form on the tubing inside the case, which can cause problems as well. So it doesn't solve the problem of condensation, although it's still a viable alternative to direct-contact TEC cooling.

 

[lapoltba]

yeah, water temp is the biggest issue. With the CrystalFontz controller you can monitor the Dallas one wire sensors. There are sensors for just about everything. By using three of the variables i mentioned (ambient teimperature, ambient humidity, and water temperature) you can control the TEC to chill the water to the proper temperature so that it will never cause condensation.


Here is a link to the dallas/maxim sensors...
http://www.maxim-ic.com/products/1-wire/

 

[Zero82z]

In that case, it'll work great. I wasn't aware it was so easy to get your hands on equipment that will control everything automatically. It's rather convenient .

 

[lapoltba]

unfortunately i am making it sound easier than it may turn out to be. I know for sure that the CF controler can handle the temp sensor but i dont know if it will directly integrate the humidity sensor, thay may be a chore. But theoretically the software can handle controling an output based on 2 temperature inputs. I am still trying to get my hands on one of These:
http://www.crystalfontz.com/product/CFA635-TMF-KU1.html

and the associated addon module for temp control.

 

[flak-spammer]

Peltier water chillers are a lot harder than they look although if you want some more advice I suggest you check out http://www.xtremesystems.org/forums/forumdisplay.php?f=94 and http://www.overclock.net/peltiers-tec/ other than that the only suggestions I can give are don't bother using computer PSU's, and don't bother getting the highest wattage TEC. Also I highly recommend using water to cool both sides so you'll need two loops. And you'll probably want to use a couple higher wattage ones say 226 or so at lower voltages maybe 6-9v to increase efficiency since you arn't looking for the maximum qcmax. Anyways I hope that's helpful.

 

[lapoltba]

thanks for the link. I was just toying with the idea i guess. If anything at them oment i may use it as a suppliment to a radiator to pull some excess heat out of my loop.