>>If you need to go VERY low then a Peltier device may not have enough
>>power. What is your target temperature range?
>
> If you need more delta T then stacked Peltiers are a possiblity. 
> This is what we use for over temperature testing in production (way 
> faster than the environmental chambers we used to use).

Stacked Peltiers do give extra temperature differential but at a 
substantial decrease in Watts of cooling as you use N layers and a 
reducing delta T per layer. For cooling you can get up to 6 layers (I 
think I've seen) but the stack is shaped something like a Christmas 
tree with a very small unit at the top and very small cooling watts 
overall.

For heating stacking may be more effective.
However, heating is not usually very difficult to achieve by other 
means.



        Russell


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