Thermoelectrics

Thermoelectric generators

Many industrial processes produce waste heat which can be difficult to utilize with traditional technologies. Thermoelectric generators can convert waste heat directly into electrical power and in this way improve the energy efficiency of the processes. Our primary focus is medium (250-550 °C) to high temperature (550-1000 °C) applications where few commercial solutions exist.

Thermoelectric power generation is based on the so-called Seebeck effect: When a temperature difference is established across a conducting material (metal or semiconductor) a voltage difference between the junctions at either end is generated. This phenomen is used in thermocouples that are extensively used for temperature measurements, but can also be used to convert heat into electricity. A thermoelectric generator can contain several hundred thermoelectric couples connected electrically. The properties of the materials determine the operation temperature of the generator. One key challenge is to develop a segmented generator capable of operating with large temperature gradients across it; this increases the conversion efficiency.

Thermoelectric generators offers several advantages:

  • no moving parts, giving reliable and silent operation
  • small units due to high power density
  • capable of operating in a wide range of temperatures
  • well suited for remote applications without grid connection
  • can be integrated with other power generating technologies, e.g. fuel cells, and in this way increase the overall efficiency  

The research at the Department of Energy Conversion and Storage include materials synthesis and processing, segmentation and construction of thermoelectric generators. modelling of individual components as well as complete modules, and characterization of both thermoelectric materials and devices. In situ studies (transmission electron microscopy, X-ray and neutron tomography) are used to identify degradation mechanisms during operation.

Contact

Nini Pryds
Head of Section, Professor
DTU Energy
+45 46 77 57 52