An example of thermoelectric module (TEM) installation in a cooler is shown in the figure. The same applies to the installation of TEM in a thermoelectric generator. The main requirement for TEM installation is to achieve the minimum thermal resistance of the contacts in the direction of the heat flow. To do this, three requirements must be met:
Contact surfaces should have minimal roughness and size deviation over the surface.
The contact surfaces of the parts must be pressed against each other. The allowable maximum pressure on the parts should be taken into account.
In the case of TEM installation without soldering (non-metallized module), there should be a liquid with good thermal conductivity between the contact surfaces. Such materials are produced by the industry and are called thermal pastes.
In order to ensure efficient and reliable operation of the module, it is necessary to install the module in compliance with a number of rules. The main requirement for the quality of module installation is to achieve minimum thermal resistance of the contacts "heat-emitting surface of the module - surface of the heat sink" and "heat-absorbing surface of the module - surface of the cooled object" in the direction of the heat flow.
Non-planarity and non-parallelism of mounting surfaces should not exceed 0.02 mm.
The module must be pressed tightly to the heat sink surface. The recommended pressing force for standard single-stage modules is 10 kg/cm2. The tightening screws must be tightened evenly, without distortion.
A heat-conducting paste must be applied to the heat exchange surfaces, ensuring thermal contact between the surfaces. The thickness of the heat-conducting paste must not exceed 0.1 mm.
Instead of heat-conducting paste, heat-conducting pads or heat-conducting glue can be used. The module with metallized surfaces must be mounted on pre-prepared surfaces of the heat sink and cold plate (cooling object). A thin layer of solder, the melting temperature of which is recommended by the manufacturer, must be applied to the cleaned and degreased surfaces. During soldering, ensure that the surfaces to be soldered are tightly pressed against each other, and that no air or flux residue remains between them.
CONNECTING TEM TO A POWER SOURCE IS CARRIED OUT IN COMPLIANCE WITH A NUMBER OF RULES :
In order to connect the TEM to the power source, it is necessary to connect the red wire to the "+" terminal of the power source, and the black one to the "-". The reverse connection will lead to the transition to the cold plate heating mode and its destruction.
It is prohibited to apply a current to the cooling TEM that significantly exceeds the Imax value. Failure to comply with this requirement leads to deterioration of the parameters, overheating and destruction of the TEM.
It is prohibited to supply power to the cooling TEM if it is not installed on a heat sink or if the thermal contact with the heat sink is poor. Failure to do so may cause overheating and destruction of the TEM.
It is prohibited to connect the TEM to an AC or pulsed current power source. Such power current does not ensure normal operation of the module.
It is prohibited to connect the TEM to a DC source with a pulsation value greater than 10%. Failure to comply with this requirement will result in a temperature difference decrease of more than 10%.
For a thermoelectric generator, the temperature on the hot side of TEM (Th) in an open circuit should not exceed Tmax. In this case, the condition Th < Tmax will be met under any electrical load.
It is prohibited to operate the thermoelectric generator in short circuit mode. This can lead to TEM damage.
