Principle
Seebeck effect
In 1822, Seebeck of Germany found that when two different conductors are connected, if the two connecting points keep different temperature difference, a thermoelectric force is generated in the conductor
ES=S•△T
Where es is the thermoelectric force, s is the rate of thermoelectric force (Seebeck coefficient) △ t is the temperature difference between contacts

PELTIER EFFECT
In 1834, the Frenchman Peltier discovered the effect of Seebeck effect, that is, when the current flows through the junction formed by two different conductors, the heat release and heat absorption will occur at the junction, and the heat release or heat absorption is determined by the current.
Q=л•I=a•Tc•I
Where: Q - exothermic or endothermic power, л - proportional coefficient, called Peltier coefficient, I - working current, a - temperature difference electromotive force rate, Tc - cold contact temperature
THOMSON EFFECT
When the current flows through the conductor with temperature gradient, in addition to the Joule heat generated by the conductor resistance, the conductor also releases or absorbs heat. Between two points of the conductor with a temperature difference of △ T, the heat release or heat absorption amount is as follows:

Principle of refrigeration Heating principle 