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Thermoelectric (TE) devices are small solid-state
heat pumps consisting of a matrix of thermoelectric
chips connected in series electrically, and connected
in parallel thermally.
Each chip consists of p-type and n-type semiconductor
pillars positioned between two ceramic plates. These
plates provide a rigid mounting surface and electrical
insulation between the heat sink and the process being
cooled.
Peltier discovered that heat is released or absorbed
when two dissimilar materials that conduct electrical
current are joined. A positive voltage applied to
the n-type material drives electrons from the p-type
to the n-type material, and then back to the voltage
supply (illustrated below).
The temperature on the cold side decreases as heat
is absorbed. By reversing the polarity the hot side
becomes cold, and visa versa.
Cooling capacity is proportional to the number of
chips and the current being supplied.
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