Thermoelectric Micro Generators
Thermoelectric generators (TEGs) are used in various applications. Their commercial usage started even earlier than thermoelectric cooling that has been developed only due to race of micro- and optoelectronics during recent few tens of years. TEGs found their applications already in the middle of 20th century.
Power conversion (direct heat to electricity) is based on fundamental physical phenomena – Seebeck effect. A thermoelectric device generates voltage when there is a temperature difference between its sides. Conversely, when a voltage is applied to it, it creates a temperature difference. At the atomic scale, an applied temperature gradient causes charge carriers in the thermoelectric material to diffuse from the hot side to the cold side.
The TEG is a unique semiconductor device of the direct conversion of temperature differences to electric voltage.
There is a number of features and advantages of thermoelectric generators: miniature design which is very flexible with possibility to scale sizes; no moving parts, very long operational lifetime – tens of years without any service. One of unique properties – possibility to convert heat into electricity starting from almost zero temperature difference.
One huge shortcoming – low efficiency of state-of-art thermoelectric generators. It is only 4-6 %. This drawback limits applications of TEGs and big power industry. The TEGs are in very hard competition now with other types of alternative power industry.
Anyway, there are some applications and they have become wider and wider where advantages of TEGs make their use very perspective. It is aso-cold microgeneration - the small-scale generation of heat and electric power. Particularly it is Green Energy Harvesting. And the applications where there are problems with supply electricity if autonomous work is required.
Among the applications: power for wireless networks, autonomous sensors and others.
Power supply for such kind of applications must be autonomous, but due to state-of-art electronics it is on milliwatt level. In most of the applications only ambient energy (heat) harvesting is used - green energy.
For such kinds of applications miniature thermoelectric generators look like a very intelligent solution.
- Very long operation lifetime without any services for tens of years.
- Energy harvesting from any heat source.
- Operation from almost zero temperature difference (heat flow).
For such applications thermoelectric generators are used of in almost the same design as thermoelectric cooling modules. In other words thermoelectric modules can be used as cooling devices as well as generators for energy harvesting.
All singe-stage thermoelectric modules produced by RMT can work as generators for low temperature energy harvesting.
In the standard specifications of such RMT’s types one can see parameters both for cooling and for generation.
For use of a thermoelectric module as a generator there are the following applications tips:
- Thermoelectric module with maximal number of pellets. Every pellet generates approximately 200 uV of voltage for one degree of temperature difference. Connected in series number of pellet pairs will provide corresponding voltage.
Maximal number of pellet pairs is provided by density of pellet packages in thermoelectric modules. RMT’s modules have one of the biggest pellet density in the world.
- Thermoelectric module with minimal resistance. Less resistance, less internal losses to internal voltage drop. And more output generated power.
Internal resistance of thermoelectric modules - other words, it is module’s AC Resistance.
In the series most powerful microgenerators – modules with lowest pellets. These modules have lowest ACR.
The company RMT has a great experience of customized solutions and can provide optimized design of thermoelectric microgenerators for customer particular requirements.
Please contact RMT for thermoelectric micro generators.