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View Full Version : Peltier Thermostat/Voltage Regulator


r_stripe
12-28-01, 08:48 AM
hey,
Im not for sure why im writing about this yet, mainly because I havent ever ran accross one of these units on the net. I was at work the other day "BORED as usual" and got to thinking about incorporating a water chiller inline with a water cooled setup. We all know a good radiator with a OC'd CPU can keep temps under 40c and sometimes at low 30c. But with my infinite boredom I got to thinking, what if i broke down and bought a dual processor board, of course it would have to be overclocked. How bad would my temps be by just using the same radiator setup. **note, Im still in the saving money process for a new system before I build my first water cooling setup :confused:. After doing alot of reading and seeing other peoples results with peltiers I had to figure out a way to incorporate it into my design. The only problem is, I want the ability to leave my house for the weekend and not be worried if my fan failed and the peltier overheated and baked my cpu. So the idea of having a peltier directly on a cpu was scrapped. So here is sorta what I have come up with. The circuit is currently built on a breadboard and seems to work good, only thing is i need a peltier to actually make sure it will handle 10amps. I asked a good friend of mine "who is an EET" and he drew a schematic for me in about 30 seconds. We are looking at about 20 bucks worth of parts from radio shack and its built. *WHAT IT DOES* In my endeavor to cool my system as much as possible without having a drop of condensation, this circuit goes in between the power supply and the peltier and has a voltage control with a gain control. Sounds indepth but its not too bad. Also there is a Thermistor which varies the voltage output depending on the temp. So there it is. With the gain maxed out this circuit **Tested and proved** can give max output voltage and drop the voltage down to 2v automatically within a 10C drop. Sorry for the rambling here, but I wish I had the money to go and buy a pelt and actually do some real cooling and testing. Just thought I would throw the idea out and see what happens. I hope to get some pics, or atleast a schematic for all of you to scan over. Its a good idea. MAX cooling with the ability to prevent over chilling???? I like it:beer:

also, this is just a temperature sensitive voltage regulator, it could be used on a heatsink fan setup, when cpu is idle and cooling down the fan would back off, when the cpu was under load and heating up the fan will speed back up.

TruckChase!
12-28-01, 09:06 AM
Hey man-

More into the cooling system itself.... Do you plan on using a radiator with this setup as well? In one of my earlier water cooling setups I used a 1 peltier unit (80watt) water chiller and got a temperature drop of approx. 1 degree below just the radiator itself... still above ambient temperature. In my setup, the peltier on the chiller was cooled by a 8" by 6" heatsink with one 80mm fan. Just the chiller itself was nowhere near powerful enough to dissapate the heatload from the pentium 2 the system was cooling.
The only chiller unit I've seen that worked well was the guy that used to run "frostyfox.com", and he used 6 80watt units with a seperate water system to cool the chilling peltiers. (chilling peltiers... sounds like a b horror flick)

The circut sounds cool tho. :)

r_stripe
12-28-01, 09:19 AM
Well my idea might not work, But I was planning on using a radiator just like any other water cooled setup, but tap into the water line after the radiator with a water chiller using a 80 to 140 watt peltier setup. I dont think it would be to wise to try to just use a water chiller by itself due to the amount of heat dissapation required and like you said 6 or 8 peltiers.....thats alot of heat to get rid of. I was thinking that if a radiator by itself could hold temps around 30 to 40c then with a decent sized homemade chiller it might be possible to pull the temps down to the 20-25c range. But I might need two peltiers to hit that temp. Just an idea, thanks for the reply..sounds like you have done more testing with this actuall setup........unfortunately It will be several months until i can actually build everything and begin testing myself.

TruckChase!
12-28-01, 02:55 PM
Here's a pic of one chiller I made that did NOT work:

http://www.bxboards.com/toby/pics/Front.jpg


That one accounted for no noticible temperature drop. There was a 72watt peltier stuck in the middle of that little sandwitch powered by an external 12v 10a power supply.

ButcherUK
12-28-01, 07:32 PM
Thermistor controlled regulatators are great, my rad fan is running off one now (172 mm fan, probe in res).