Peltier Cooler Test

This Peltier cooler just emerged from a pile o’ stuff on the Electronics Workbench, so I combined it with a scrap CPU heatsink (using plain old water as “thermal grease”) and fired it up to get some quick numbers for future reference.

Peltier cooler test lashup
Peltier cooler test lashup

It draws 3 A (the bench supply’s current limit) at 5 V. The cold side got down to 19 °F with the hot side at 75 °F: ΔT = 56 °F.

That’s with zero thermal load, other than whatever arrives from plain old air and those two plastic clamps. It looks like a nice one, so it’s maybe 10% efficient and could pump a watt, barely enough to cool a simple circuit.

Freezes a drop of water just fine, though.

The I-V curve is nearly bar-straight over the first five volts: call it 620 mΩ. The thing would draw 7.5 A at 12 V, call it 90 W, and could pump maybe a whopping 9 W from the cold side.

Actually getting good numbers would require some serious work that I’m not up for. In particular, everything has a serious temperature coefficient, so nothing would be the way it looks. I have doubts about the efficiency guesstimate; I’d like to actually measure that sometime.

But it confirms my opinion of Peltier coolers between hundred-watt CPUs and water-cooled heatsinks: pure delusion.

8 thoughts on “Peltier Cooler Test

  1. Wait, people are mounting Peltier elements on top of their CPUs? I’ve never seen that. :P

    1. In the privacy of their own basements, they’re up to no good…

      My buddy Eks gave me a bag of ancient Peltier coolers with some penciled notations that indicate the nominal cooling capacity is a bit under half the input power. The data sheets suggest that’s with no temperature differential across the elements, which isn’t particularly useful.

      I could gang ’em up to cool the basement and heat the hot box disinsector, I suppose…

  2. You are thinking about it backwards :-) Peltier coolers make better Peltier heaters than coolers; they put out more heat than they take in as electricity!
    – Steve

    1. *facepalm*

      Of course! Why didn’t I think of that?

      If I clamp a dozen of ’em in series, I can build a smelter…

    2. Looking through Wikipedia it seems that it’s known as a Peltier element or module in most languages, rather than a Peltier cooler (although I suppose light cooling is its most typical use, at any rate :P).

      1. Yeah, when you need heating, you have plenty of cheaper and more effective ways to get it done…

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