Thermoelectric generators for use in space and human bodies

Waste heat is one of the largest industrial losses. Thermoelectric generators (TEGs) are an interesting technology which can be used to recover some of the waste heat into electricity and thus reclaim energy that would otherwise be lost.
A new EU-funded project “Nano-carbons for versatile power supply modules” (NanoCaTe), aims to develop thermoelectric harvesters which are able to operate in the temperature range from room and body temperature to 100 °C.

Difficult temperaturerange
The temperature range of up to 100 °C is important because it accounts for more than 50% of the total heat generated in industry and can be found in virtually all areas of industry and building; but waste heat in that temperature range is also often the hardest to recover cost-efficiently.
 “The NanoCaTe project has the tasks to design, model and test two kinds of TEG-modules using on one hand up-scalable bulk modules and on the other miniaturization techniques like thin film printing to produce smaller modules”, explains professor Nini Pryds, head of thermoelectric research at DTU Energy Conversion and work package leader at NanoCaTe.

Body and outer space
One TEG-module will be small and flexible, able to generate electrical energy from body heat in order to power small miniature sensors inside or outside the human body. Another TEG-module will be larger, more compact and used in spacecraft in outer space to harvest energy from the waste heat of the electronic equipment’s in the spacecraft.
The two TEG-modules will vary greatly in size, flexibility and expected use, but both need to be as small, as efficient and as affordable as possible. The NanoCaTe-project is expected to not only develop the modules, but an entire concept ranging from harvesting the energy, storing it and use it in this case in smart sensors.

Light, small and efficient
The NanoCaTe-project is divided into work packages being done by 13 different universities and industrial partners from Germany, Finland, Austria, Spain and Denmark.
The Frauenhofer Institute, Germany, is the coordinator of the project while DTU Energy Conversion has the critical role of building and testing the TEG-modules.
“Our job will be working directly with producing thermoelectric materials, testing them and building TEG-modules”, says professor Nini Pryds and explains how DTU Energy Conversion together with the other partners will be researching in new methods to make thermoelectric composite materials based mostly on carbon nanotubes. This will make it possible to enhance the fundamental properties, the power and energy density of materials, resulting in environmentally friendly TEG-modules which are lighter, smaller and more efficient.

Financed by FP7
“We’ll probably use carbon nanotubes and polymers for the flexible TEG-modules used for body sensor application and carbon nanotubes and bismuth telluride (Bi3Te3) for the spacecraft components, but that remains to be seen,” explains Nini Pryds.
The NanoCaTe-project is funded by EU’s 7th Framework Programme and is expected to be finished in 2017.