Hello,
I'm designing a 'thermo table', consisting of a 150 x 150 x 4 mm aluminium surface (6" x 6" x 1/6"), which has to be kept at a precise temperature throughout (+/- 0.1 degree centigrade). Since both heating and cooling are required, the whole design is based on one or more Peltier elements.
Ideally, one would use a Peltier element of comparable size as the aluminium surface, to minimize temperature differences due to small local heat losses. However, for reasons of cost and available electrical power (100W max), I'm limited to commonly available Peltier elements with a 40 x 40 or
50 x 50 mm surface area.So I thought I'd use four identical 25W Peltier elements (40 x 40 mm) instead of one 100W Peltier element (50 x 50 mm). My question: is it better to connect these Peltier elements in parallel or in series? In other words: is a Peltier element's heat transport mainly determined by voltage difference or by current? Any ideas are appreciated.
And oh, I thought about using much thicker aluminium to minimize local temperature differences, but with the above dimensions, I already have a heat capacity of > 200 J/C, so with 100W power it already takes at least 2 seconds to heat it up by one degree. Doubling the thickness also doubles this time, and that quickly becomes a problem: users will want to change the temperature often, and don't want to wait several minutes every time until the temperature settles to its final value.
Thanks in advance for any ideas.
Richard Rasker