Process Heat

Integration of thermoelectric generators in porous gas burners

Using thermoelectric generators (TEG) can increase the efficiency of combustion processes by producing electricity in addition to heat. The direct conversion of waste heat to electricity improves energy efficiency. The project partners prove that porous burners are suitable for combination with TE elements.

 

Summary

Even today, heat generation by means of combustion entails substantial heat loss. In this regard, porous burners represent a novel combustion technology in which suitable fuels are combusted flamelessly in a porous structure by incandescent ceramic foams. The efficiency of such porous burners can be increased by employing TEG. By using 1 to 10% of the combustion heat capacity, a temperature difference created in a TEG can generate electrical energy. This way, the fuels' energy content can be utilised to a higher degree.

The project examined energy-related exploitation of waste heat as well as of the porous burner housing's surface temperature using purchased TEGs. Using module units consisting of four parallel thermo-generator cells, the potentials for electricity generation were investigated. Optimum connection of the elements to the burner's surface is just as important here as setting the ideal operating temperature. 

Results:

  • General suitability of a plane burner surface for effective electricity generation was successfully proved.
  • The electrical output of the TEGs is not dependent on burner output. This means that the TEGs can operate at optimum electrical efficiency throughout the burner's entire operating range.
  • Different electrical output was generated at comparable temperature differences. Contrary to expectations, the electrical output is not proportional to the temperature difference.
  • The low electrical efficiency is the result of poor contacting between the TE elements and the burner.
  • Water is a suitable energy sink for creation of the temperature difference.
  • The TEGs available do live up to the expectations in regard to electrical efficiency, mechanical stability and general reliability of operation.

Project Participants

Implementing Institution

promeos GmbH

More Project Informations

Project title:  TEG-Brenner – Neuartiger stromliefernder Gasbrenner durch Integration von Dünnschicht-Thermoelektrogeneratoren in Gas-Porenbrenner

Project number:  01LY0911A

Project period:  2009 - 2011

Project region:  Germany (Bavaria)

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Source: German National Library of Science and Technology Hannover (TIB)