Let’s Know about Thermal Generator!

Thermal generator works on the concept of Seebeck effect. According to Seebeck effect, one side of the device is heated up in a manner that its temperature is greater than the other side and hence difference in voltage will be established. It is also called as thermoelectric generator or Seebeck generator. It can be defined as a solid state active device that is used to convert the heat directly into electrical energy by using the concept of seebeck effect. It also exchanges electrical energy into thermal power energy for heating or cooling.

Configuration of the thermal Generator:

The elevated temperature is provided by the heat source which flows directly to heat sink through thermoelectric converter.  Heat sink is always maintained at below temperature as compared to heat source. This difference of temperature is responsible to produce direct current (DC) for current loading (R_L) using a terminal voltage (V) and terminal current (I). Thermoelectric power generator is also classified as direct power conversion as they don’t have intermediate energy conversion process. Electrical powers are generated through l², R_L and VI. Consider the following figure:

Traditionally only three types of thermoelectric material are used in semiconductor for low thermal conductivity and high power factors which are bismuth tellurides (Bi₂Te₃), lead telluride (PbTe) and silicon germanium (SiGe). These materials are expensive compound because of rare availability. Hence, now a day, nanotechnology is being used for thermal conductivity of semiconductors, however, manufacturing of nano materials are still very challenging.

Uses of thermal generator:

·        In power plants to convert waste heat into additional electrical power
·        In automobiles as automotive thermoelectric generators to increase fuel efficiency
·        Radioisotope thermoelectric generator as space probes
·        To construct fossil fuel generators
·        Solar source generators
·        Nuclear fueled generators

Working of thermal generator:

Thermal generator generates the electricity by moving of electrons. Electron moves in a metal just like fluids flow in pipe. At the time of heating of thermoelectric material electron move speedily from hot end to cold end which causes electric current. When the large temperature difference is created by electrons, more electric current will produced and hence more electric power is generated.

Now the problem arise is that when start the heating process, cold side of the generator also starts heating. Nevertheless, we need a temperature difference between thermoelectric materials to generate electricity. This task is accomplished by heating water in the power pot to create heatsink as water can keep more heat several times as compared to aluminum per pound. The water can maximum hotter by 212F (100⁰C) at a boil. Thus, the cold side of the thermoelectric generator is limited to this capacity. So, we always need a something watery in the powerpot to avoid overheat of generator.