The Mushkin peltier heatsink revisited ( future peltier owners must read)

[Stryker]

Besides the problems with screws and backwards wiring ( see last post on this subject)
there are other problems future peltier owners should be aware.

I noticed that as soon as you power down your system the peltier pads on my heatsink do for a lack of a better term, back flush the heat. By that I mean the heat that is still remaining in the heatsink gets drawn back into the peltier and thus your cpu gets hotter before it gets cooler.

Another thing I noticed is they produce a lot of heat, I mean a lot. The temps I got off of the heatsink were in the 130's. This creates two problems, the first is it makes the motherboard hotter. Second, with three fans on the heatsink , that produces a ton of hot air
circulating in your box. I have a tower and my hard drive sits at the top of the tower next to the heat exhaust fan so as to suck the hot air off the hard drive and out of the box.
Because the peltiers produce so much heat, even with the cover off my box, my hard drive runs hotter.


Being worried about the back flush heat on my cpu I went to Fry's and purchased two small 3/4 by 3/4 peltiers. There was room on each side of the large peltiers already installed on the heatsink. These little peltiers only run on 1.5v so I also purchased a 1.5 v AC adapter.
I wired up the little peltiers to the AC adapter and put the adapter on a power strip. Now when I power down the computer I leave the little peltiers on a couple of minutes to off set the flush heat. I know the little peltiers will back flush but the heat will not be as intense plus there at the far sides of the cpu case away from the processor it self.


This caused yet another problem, the AC adapter gets so hot I am afraid it will explode!
In fact I put a thermometer probe on it and it read 140.7F!

Moral of this story, peltiers are more trouble than there worth. Believe me this is the last peltier type cpu cooling system I will even install.

[CMonster]

I am laughing with you not at you. Yeah, heat = heat = more heat at a higher price.

Surface area is very important, in the case of heatsinks bigger is probably better. Even in radiator and refridgeration systems, it is not the fluid or refridgerant that does the cooling, that is just the medium by which heat is carried off to a larger surface area where it is radiated off into the air (another fluid).

The medium is important too, for example a copper heatsink should work better than an aluminum one. But sooner or later you reach a maximum ratio of heat transfer with the available materials.

[Stryker]

Ah! Chuckiechan
You have given me an idea, I will just get a
another AC adapter and run one fan off it. I will point the fan right at the cpu-heatsink. I will run it for several minutes like the small peltiers I mentioned.

[This message has been edited by Stryker (edited 02-14-99).]

[chuckiechan]

The obvious next step is to wire in a rechargeable battery to run the fan for a short time after shut-down.
There are some very brainey people on this site who can offer you (& me) some know-how or if this is even feasible.

[gohmdoree]

when you get that working, can you let us know how it goes?

[shocker]

Hey Stryker,

I've been messing around with a generic peltier cooler today.

I noticed that the power from my computer's power supply put the thing into overdrive. I mean it got HOT. At 3.3 volts, my power supply cranks out 16amps.

I started reading through the documentation and in addition to voltage, amps play a major role in how the peltier operates. I hooked up a 1000ma external power supply and that did the trick. The peltier worked, but it didn't get so hot. It ran best at 4.5-6 volts, any higher and it got hotter, even 3 volts felt cool on the processor side, warm on the other.

Worth a try if you're into experimenting.

[chuckiechan]

I have found a workable system to use the peltier:
Mine is a TEC1-7103, 30 x 30 mm, 6 to8.1 V,
3.3 amp.
What I did was hook the device up to two 2.2 ohm, 5 watt ceramic resisters, one on each leg of the device. The voltage performance is
not within spec, but the temperature performance is. Using a large steel heat sink (for unlimited capacity), It gets 48-50 deg F. cold, and 90-94 deg F hot. For a 40 degree spread. If you shut down the power, you should only get chip temp, plus 40 deg max rise, and don't forget that the heat sink is still pulling.
P.S. I hooked it up to the 5 V. leg (red)

happy clocking...CC


[This message has been edited by chuckiechan (edited 02-22-99).]