The Thermoelectric effect (TE) comes in two variants:
- The Seebeck effect makes it possible to turn a heat flow (based on a temperature difference) into electric power.
- The peltier effect does the reverse: it turns an electric current into a temperature difference across the two sides of the device.
The fundamental mechanism is a p-n-transition. So you have two different semiconducting materials, which means that the electrons are on different energy levels on both sides. When the electrons move from one side to the other, they have to absorb energy from the environment to get on the higher energy level themselves (p->n transition), or they give off energy (n->p transition), thus cooling or heating the environment.
With this technology, it is possible to build solid-state heat pumps that generate a temperature difference from an electric current with no moving parts! (i don’t know about efficiency or cost)
ok but what if you stack multiple of them on top of another? then the temperature drop across each one is rather small but since they stack, it adds up. would that be a possibility?
You can stack them to get a lower temp, but efficiency is still poor.
i looked it up. no, stacking them does not magically improve the efficiency. for example, for a ΔT = 1 K you have like 20 mJ of electric energy input to move 1 J of heat across the device (so the coefficient of power is around 50, which is crazy damn high)
if you have ΔT = 2 K then you need 40 mJ of energy input to move 1 J of heat across.
but if you use two stacked devices with ΔT = 1 K each, then you need 2 * 20 mJ of energy input to move the 1 J of heat across both devices to achieve a total ΔT = 2K. so it does not actually save energy.