# Thermocouple power

• Subject: [amsat-bb] Thermocouple power
• From: G0MRF@xxxxxxx
• Date: Mon, 26 Feb 2007 18:46:47 EST

Last week there was an interesting debate about raising the altitude of a
satellite by using magnertic fields.

Carrying on the wacky ideas theme, I've been looking at producing power by
using thermocouples and not solar cells.

Question: Does anyone know the 'current' or the impedance of the voltage
source represented by a thermocouple?

A thermocouple generates an emf (voltage) proportional to the difference in
temperature between its two junctions.

Given that we know a white object in space gets very cold, while   Aluminium
gets very hot it's interesting looking at the possibility of  thermocouple
power....Even if it's just to understand its limitations

A thermocouple can be made very small so it should be possible to
manufacture an array of them in a reasonable space.

Example:  A junction of two wires, one made from constantan and  one from
Chromel will generate a voltage of 58 microvolts for every degree  difference
between the junctions.

That means for a 100 degree C difference you  generate  5.8mV.
For 350 junctions in a chain you generate 2.03 V
and for 6 chains (if you wanted to risk all those junctions in series) you
could have 12.18V

But.........how much power can you draw from it ??

73

David

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