How Do 38W and 92W Peltier Cells Compare in Efficiency?

[junkfunkydude]

A while back, I purchased a 38W peltier cell on ebay. It wasn't powerful enough, so I'm looking at something along the lines of a 92W. I noticed, however that my 38W and the 92W have the same dimensions and the same number of junctions. Also, dT of the 92W is only 1 degree C above the 38W.

How is this possible?
Are the sellers providing false information?
Is one made out of a material with a higher Seebeck coefficient?
If so, will one be more efficient than the other?

Also, a general explanation as to how the different factors effect a cell would be greatly appreciated.

 

[vadslram]

I remember reading that there is some falloff of efficiency with size and that using multiple cells is a better way to go.
I got my first chip on a 80286 processor cooler (6 mhz ) and been playing with them ever since. I heard that the 08 Chrysler Sebring is coming out with heated and cooled cup holders...I can bet how they're going to do that.