[amsat-bb] Re: Thermocouple power

[Steve Holly]

Like one of these...   http://www.hi-z.com/websit04.htm

More Thermoelectric Generator Manufacturers referenced here:
http://www.peltier-info.com/generators.html

73,
Steven WI2W

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of G0MRF at aol.com
Sent: Monday, February 26, 2007 6:47 PM
To: amsat-bb at amsat.org
Subject: [amsat-bb] Thermocouple power


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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