EU research project INTEGRAL
The European Union-funded (EU) project* INTEGRAL focuses on the recovery of heat energy using thermoelectric material and forms the framework for Isabellenhütte’s “material production and process development” project. Isabellenhütte is responsible for establishing and developing one of three pilot projects geared towards producing thermoelectric half-Heusler compounds in large volumes. The overarching goal of the project is to increase the level of technological maturity of this form of energy recovery from 4 (experimental setup in the laboratory) to 7 (prototype in use) by 2019.
In collaboration with the Swedish truck powertrain cooling manufacturing TitanX, the Fraunhofer Institute for Ceramic Technologies and Systems IKTS and the British engineering service provider Ricardo, Isabellenhütte is currently developing a thermoelectric generator (TEG) that can be coupled to truck exhaust systems within the scope of the EU’s INTEGRAL (INitiative To bring 2nd gEneration of thermo-electric Generators into industrial ReALity) project.
TEG recovers energy through half-Heusler compound The TEG consists of two heat exchangers and an active thermoelectric half- Heusler compound placed between the heat exchangers. One heat exchanger gathers heat from the exhaust gases, which is then channelled by the hot- side exchanger to the active thermoelectric material. The heat flows through the thermoelectric material and is then collected by the second heat exchanger and dissipated. The thermoelectric effect allows part of the heat flow to be converted into electrical energy.
Research has massive potential
This area of research offers a huge amount of potential, with the automotive industry, power plants, heating system manufacturers and consumers alike able to benefit greatly from this form of energy recovery. After all, some 50% of all energy generated worldwide is lost in the form of heat. In vehicles, this figure is closer to 70%. So far there has been no series-ready technology providing a way to use this energy.
The half-Heusler compound used in this process is extremely efficient. It is capable of converting 5% to 7% of the channelled heat flow into electrical energy. Half-Heusler compounds are also much more stable than alternative materials such as silicides and Skutteridites. They combine high mechanical durability with excellent thermal and chemical resistance.
Pilot production set up
Isabellenhütte intends to establish pilot production at its Dillenburg site in 2017, which should be able to produce large amounts of half-Heusler compounds in an industrial environment. Following production, the material is to be installed in a generator developed in conjunction with TitanX and Ricardo before being submitted to a practical test. In this test, the generator will be placed on a hot gas test bench that simulates the exhaust system of a truck.
Maintaining a high level of quality throughout production is a major challenge in half-Heusler compound production. The aim of the system is to smelt 20kg of high-quality half-Heusler material. The smelted blocks are then cut into slabs, known as wafers, and then into components measuring just a few millimetres in width. In terms of quality, the aim is to achieve a yield rate of at least 95%. These half-Heusler components are installed in the generator by TitanX.
By launching the production system in 2017 and unveiling subsequent process developments by the end of the project in 2019, Isabellenhütte intends to prove that the industrial production and application of half-Heusler functional materials is possible and a commercially and ecologically worthwhile undertaking.
Isabellenhütte Heusler GmbH & Co. KG#
Eibacher Weg 3 – 5
Dipl.-Ing. Daniel Zuckermann
Assistant Manager R&D Alloys
Tel.: +49 (0)2771 / 934-300
Mobile: + 49 (0)170 / 779 0830