Thermoelectric cooler (TEC) is a semiconductor device which is characterized by unique heat pump performance with high efficiency, compactness and durability. The unique ability of TECs to heat and cool, permits them to lower temperature of an object below ambient as well as to stabilize temperature of objects in widely varying ambient conditions.
Here we mention some application tips that can help in optimal use of TECs.
Heat dissipation is crucial to the overall thermoelectric system operation. For proper thermoelectric management, all TECs require a heat sink and will be destroyed if operated without any.
TEC provides only temperature difference between hot and cold side. If waste heat dissipation is limited and hot side is overheated then cold side temperature moves up. In the case to keep cold side temperature constant more power is needed.
Or, if heat dissipation by heat sink is too low, overheating of hot side can lead to damage of TEC (by melting of internal solder)
Heat sink performance parameter - thermal resistance. It is the measure of the ability of the sink to dissipate the applied heat and is given by:
where Rτ - thermal resistance in K/W; Th - heat sink temperature in K ; Ta - ambient temperature in K; Q - heat load into heat sink in watts (includes heat absorbed + TEC power)
The objective of the heat sink selection (among standard ones) or of it custom design is to minimize thermal resistance. This is achieved through exposed surface area and may require forced air (by fan) or liquid circulation.
There are three basic types of heat sinks:
|Type of Heat Sink||Thermal Resistance (typical) °C/W|
|Forced convective||0.02 ...0.5|
The natural convective heat sink is the simplest solution but lowest heat transfer ability, liquid cooled heat sink has best performance but it is much more expensive and complicated.
Selection of optimal heat sink is always a compromise solution.
Never use TEC without heat sink.
Proper heat sink contribute to TEC efficiency.