> Btw these don't really cool your drink cans and bottles 
> (in reasonable
> time, that is). All they do is keep your already cool 
> drinks cool.

In many cases you are probably correct.
This would depend on ambient temperature, quality of 
insulation, Peltier cooling Watts and, extremely 
importantly, the effective C/W rating of the output 
heatsink.

Imagine you were trying to remove 10 Watts of output heat. 
A 1 degree C per Watt heatsink is a bit of an engineering 
marvel. A 5 degrees C per Watt heatsink is much more 
achievable. In the first case the heatsink would rise about 
10C ambient and in the latter, about 50 C.  Peltier cooling 
ability drops with temperature differential and 30C is 
probably the best one could hope for. A heatsink 10C above 
ambient may deliver 20C below ambient cooling in a well 
designed system. A 50C above ambient warms your drink. 
Bearing in mind that the electrical input PLUS the extracted 
energy must be removed via the heatsink, heating on the cold 
side wrt ambient is entirely possible.

So. A well designed mega-heatsink with an efficient fan may 
indeed produce a good result.

But, if real cooling power per Watt is more important than 
cost, dash down to Walmart (or perhaps some other (even) 
more employee friendly store, and buy a Stirling based 
cooler with vastly better coolth per Watt.

        http://www.yourvalu.com/product/5726750
        http://www.amazon.com/review/product/B000A1FCIE?showViewpoints=1
        http://www.rvnewsdaily.com/index.php?topic=RV_Supplies_And_Acce


And BTW - if James tells you that there are no Stirling 
based products on the market, tell him there are some really 
cool ones available [groan].




        Russell




-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist