Design Issues and Future Perspectives for Magnetocaloric Energy Conversion

Abstract

This chapter provides information about the design characteristics for particular types of magnetic refrigerators and heat pumps. The sections therefore indicate the different categories to which a particular magnetocaloric device can belong. For these we show the different design configurations. These are related to linear devices that are based on the linear movement of a magnetic field source or magnetocaloric material; rotary devices, which are based on the rotation of the magnetic field source or the rotation of the magnetocaloric material; and static magnetocaloric devices. Some of the configurations were already applied in research. However, we also present a few new solutions, which are based on our research experiences and which might be applied in future studies and related devices. We again address the importance of the thermal diode mechanism in combination with the active magnetic regeneration (AMR) principle. In addition, a note on power generation is added, with a brief review of the existing work in this particular domain. By pointing out the most successful design approaches, this chapter also serves as a future guideline on the magnetic refrigeration and heat pumping.Since the magnetocaloric devices will, in the following decade, most probably start to penetrate some market niches, it is important, before starting, to address the standardization (or classification) issue relating to magnetocaloric energy conversion. Only a few studies have been performed in this particular and very important domain. However, the research community in the field of magnetocaloric energy conversion decided to enter such a standardization process.For instance, for devices, Scarpa et al. in 2012 [1] proposed a classification method for room-temperature magnetic refrigerators. They proposed a classification of magnetic refrigerators using 12 different criteria, marked by the numbers 1-12. Here, we denote these; however, we marked in bold a slight addition and changes that we think should be included or modified in such a classification.(1) Device type (0 for single-stage cycle without regeneration, 1 for passive regeneration, 2 for active regeneration), (2) magnet type (0 for permanent, 1 for electromagnet), (3) type of permanent magnets (0 for simple magnets, 1 for 2D magnets with Halbach principle, 2 for 3D magnets with Halbach principle),