Frequently Asked Questions

A: TEGs operate through the intercoupling of thermal and electrical currents in the active thermoelements. There are actually two subsystems that must be accounted for in a design -- the thermal circuit and the electrical circuit. Both subsystems are optimized through impedance matching. For thermal impedance match, the ∆T across the TEG should match the ∆T across parasitic (non-productive) elements. The TEGs designed by TXL Group have elements with high thermal resistance and a large length to area (L/A) ratio to increase module gradients when thermal energy flux is limited.

A: Making a low thermal resistive contact to the heat source and heat sink is always important in thermoelectric applications regardless of whether they are for generation or for heat pumping. Heat sink grease can be part of a low resistance solution.

A: For a given module, voltage can be increased by increasing the temperature difference across the module (that is, increasing the ∆T). Alternatively, a voltage boost circuit can be used to convert low voltages from the TEG to a higher voltage.

A: There are three options. First, if the electrical load is fixed then as long as the temperature across the module is held constant, the output voltage across the load will remain constant. Second, between the TEG and the load, add a specialized electronic circuit called a regulator. Third, use a voltage boost circuit to increase voltage from the TEG to a voltage that is higher than the desired output voltage and then use either a battery of the desired voltage or a Zener diode to clamp the output to the desired setpoint voltage.