From: Richard Prosser <rhprosser@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Fri, 26 Feb 2021 22:21:40 -0800
Subject: Re: [EE] Low power energy measurement
Thread-Topic: [EE] Low power energy measurement
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If your expected voltage is OK, how about a cheap USB power monitor? eg:-
https://www.aliexpress.com/item/4001285945153.html?spm=3Da2g0o.productlist.=
0.0.277475cefS1yh4&algo_pvid=3D9919f5ca-6878-4b7c-92aa-1b45bdc6405a&algo_ex=
pid=3D9919f5ca-6878-4b7c-92aa-1b45bdc6405a-1&btsid=3D0bb0622916144067450612=
691e8bfb&ws_ab_test=3Dsearchweb0_0,searchweb201602_,searchweb201603_

RP

On Sat, 27 Feb 2021 at 11:49, Sean Breheny <shb7@cornell.edu> wrote:

> Just an off-the-top-of-my-head idea - there are quite a few peltier-power=
ed
> fans for wood stoves available for about $30 US online. They sometimes ha=
ve
> long-term reliability problems but it might work well for some experiment=
s.
>
> You're probably aware of this but there is a fundamental thermodynamic
> limit which depends on the temperature difference between the hot and col=
d
> sides. The greater the difference, the more energy you can theoretically
> extract. This is called Carnot efficiency and the formula is 1-Tc/Th wher=
e
> Tc and Th are the kelvin temperatures of the cold and hot sides,
> respectively. Then, beyond this, each technology for extracting said ener=
gy
> has its own limitations. I would expect that for a heat source at 100 deg=
 C
> above room temp (Carnot efficiency 25%), thermoelectric generators are
> going to be limited to extracting about 5% of the heat flow at best, and
> about 2% is probably more realistic.
>
> On Fri, Feb 26, 2021 at 1:38 PM Neil <picdude3@narwani.org> wrote:
>
> > I'm trying to get a ballpark idea of how much energy I can get out of a
> > small thermoelectric generator over an extended period of time.
> > Anyone know of a simple circuit/project or even product I can pick up
> > that would let me do this relatively easily (for now)?  I just want to
> > see if an idea is viable before investing too much into this.
> >
> > Cheers,
> > -Neil.
> >
> > --
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