# Re: NFC: Peltier Junction Cooling

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-----Original Message-----
From: D. Martin Moore <archimedes at master_localink4.com>
To: nfc at actwin_com <nfc at actwin_com>
Date: Wednesday, January 06, 1999 12:02 PM
Subject: Re: NFC: Peltier Junction Cooling

>Here is what I found at All Electronics (www.allcorp.com)
>
>12V, 8.5A yields a temp of 0C on one side and 50C on the other.
>The device is about 1.5 inches square.

Electrical work:  W = VA = 12*8.5 = 102 watts.
W/Q >= 1 - Tc/Th, so Q <= W/(1 - Tc/Th).
Tc = (0 + 273) K = 273 K.  Th = (50 + 273) K = 323 K.
Therefore, Q <= 102 watts/(1 - 273/323) = 659 watts.

So this particular device could transfer _at most_ 659 watts (2249 Btu/hr).
The actual amount is probably a lot less.

If we knew the actual heat transfer rate, we could compare the efficiency of
the Peltier junction with that of an ordinary refrigerator or air
conditioner.  (Just convert the heat transfer from Btu/hr to watts.)

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