An efficient heat-exchanger requires a large surface-to-volume ratio. This can be achieved, for example, by the preparation of fine channels in the body of the heat-exchanger, which allows a fast heat transfer with the heat-exchange fluid. Additive manufacturing provides the freedom to design complex geometries. Furthermore, the production by additive manufacturing can reduce the consumption of raw materials by up to 75%, as conventional machining is avoided, thus also reducing the environmental impact.
We prepared La(Fe,Si,Co) complex geometry heat-exchangers with fine channels using selective laser melting (see the image below). Now we apply the selective laser melting technology to other magnetocaloric materials such as Heusler alloys. The major challenge is the preservation of the functional properties as in bulk material. Therefore, we investigate the magnetic, magnetocaloric, elastic and microstructural properties of bulk and selective laser molten Heusler alloys to identify the correct processing parameters.
Wavy-channel and transverse-fin blocks out of LaFe10.7Co1.3Si prepared by selective laser melting1
As the next step, we are considering the modelling and fabrication of bionic heat-exchanger geometries. Such Nature designs like, for example, human blood vessels exhibit low pressure drop and extremely good heat transfer properties, which make them a perfect model system to improve heat-exchanger design. A further opportunity is the modelling of locally functionalized heat-exchangers. Here we would like to extend the only structural design by a local design of the functional properties of the heat-exchanger material. The optimisation of heat-exchangers is extremely important since an efficient heat-exchanger is one of the key factors for future refrigeration applications.
1J. D. Moore, D. Klemm, D. Lindackers, S. Grasemann, R. Träger, J. Eckert, L. Löber, S. Scudino, M. Katter, A. Barcza, K. P. Skokov, and O. Gutfleisch, Selective laser melting of La(Fe,Co,Si)13 geometries for magnetic refrigeration, Journal of Applied Physics (2013), https://doi.org/10.1063/1.4816465