Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

More efficient energy harvesting with magnets

09.01.2019

Scientists at the Leibniz Institute for Solid State and Materials Research Dresden (IFW) have developed a new magnetic generator to convert waste heat into electricity. A clever arrangement of the components has succeeded in improving the electrical yield by orders of magnitude. Thus thermomagnetic generators qualify for application-suitable technology for the energy harvesting of from waste heat.

Many processes in everyday life and in industry generate waste heat that is not hot enough to be used effectively. As a rule, it is discharged into the environment unused, for example, in the case of large IT servers or at the exit of power plant cooling towers.


Thermomagnetic generator on a laboratory scale

Photo: IFW Dresden

To date, there are very few technologies available for the conversion of low temperature waste heat into electricity. Great hopes are placed on so-called thermoelectric materials, in which an electrical voltage can be generated directly from the heat difference of the material.

Another possibility is the use of thermomagnetic generators which are based on a cyclic change of magnetisation with temperature. According to Faraday’s law, the switches of magnetic flux induce a voltage. One prerequisite is that the magnetic properties of the material depend very much on the temperature.

A suitable material for thermomagnetic generators is, for example, the alloy of the elements lanthanum, iron, cobalt and silicon, which is also used for magnetic cooling applications. Below 27 degrees Celsius, the material is magnetic, while at higher temperatures it is nonmagnetic.

If the material is alternately brought into contact with warm and cold water, the magnetization of the material changes continuously. This in turn causes a voltage to be induced in the applied coil that can be used by a consumer.

This principle of thermomagnetic generators was developed more than one hundred years ago. So far, however, the yield has been significantly lower than that of thermoelectric generators, although theoretical calculations show that much better ratios should be achievable.

Scientists from the IFW Dresden now succeeded in improving the performance of thermomagnetic generators by orders of magnitude. In cooperation with the TU Dresden and the Federal Institute for Materials Research (BAM) in Berlin, they introduced a clever arrangement of the magnetic circuit with two magnetic sources and two elements of the thermomagnetic alloy.

The individual components are connected to magnetically conductive material, which is wrapped in two places with a coil. A cold-warm alternating bath of the thermo-magnetic elements now causes them to conduct or interrupt the magnetic flux alternately.

This results in a constant reversal of the magnetic flux in the circuits, whereby an electrical voltage is induced in the coils. With a voltage of 0.2 volts and a power of 1.24 milliwatts, the new thermomagnetic generator is not only orders of magnitude better than its predecessors, but is also becoming a possible alternative to thermoelectric generators.

In addition, the authors still see many opportunities to further optimize these key figures. They are very optimistic that this energy conversion technology has the potential to become competitive with thermoelectrics for energy harvesting near room temperature.

Wissenschaftliche Ansprechpartner:

Dr. Sebastian Fähler
s.faehler@ifw-dresden.de
IFW Dresden
Phone +49 (0) 351 4659 588

Originalpublikation:

A. Waske, D. Dzekan, K. Sellschopp, D. Berger, A. Stork, K. Nielsch, S. Fähler: Energy harvesting near room temperature using a thermomagnetic generator with a pretzel-like magnetic flux topology. Nature energy 2018, DOI 10.1038/s41560-018-0306-x

Weitere Informationen:

https://www.nature.com/articles/s41560-018-0306-x
https://www.ifw-dresden.de/de/news-events/

Dr. Carola Langer | idw - Informationsdienst Wissenschaft

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Bifacial Stem Cells Produce Wood and Bast

Heidelberg researchers study one of the most important growth processes on Earth

So-called bifacial stem cells are responsible for one of the most critical growth processes on Earth – the formation of wood.

Im Focus: Energizing the immune system to eat cancer

Abramson Cancer Center study identifies method of priming macrophages to boost anti-tumor response

Immune cells called macrophages are supposed to serve and protect, but cancer has found ways to put them to sleep. Now researchers at the Abramson Cancer...

Im Focus: Ten-year anniversary of the Neumayer Station III

The scientific and political community alike stress the importance of German Antarctic research

Joint Press Release from the BMBF and AWI

The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...

Im Focus: Ultra ultrasound to transform new tech

World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles

The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.

Im Focus: Flying Optical Cats for Quantum Communication

Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.

In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Our digital society in 2040

16.01.2019 | Event News

11th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Aachen, 3-4 April 2019

14.01.2019 | Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

 
Latest News

A New Home for Optical Solitons

23.01.2019 | Physics and Astronomy

Graphene and related materials safety: human health and the environment

23.01.2019 | Materials Sciences

Blood test shows promise for early detection of severe lung-transplant rejection

23.01.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>