Analyzing the energetic performances of AMR regenerator working with different magnetocaloric materials: investigations and viewpoints

Magnetic refrigeration is an ecofriendly solid state technology employing magnetocaloric materials in an Active Magnetic Regenerating refrigerant cycle (AMR), a Brayton-based thermodynamical cycle. Magnetic refrigeration is based on magnetocaloric effect (MCE), a physical phenomenon that couples an external magnetic field with the magnetic moments of magnetocaloric materials. In the case of ferromagnetic materials, MCE is a warming as the magnetic moments of the atom are aligned by the application of a magnetic field, and the corresponding cooling upon removal of the magnetic field. Gadolinium is the benchmark material for magnetic refrigeration in room temperature range, thanks to its marked magnetocaloric effect which is maximum at 294 K. In this paper the results of numerical investigations on magnetocaloric materials are presented: the energetic performances of different magnetocaloric materials have been investigated through a two-dimensional model of an AMR regenerator. The model has been previously experimentally validated with a Rotary Permanent Magnet Magnetic Refrigerator. Exploring the behavior of the regenerator under variable working condition, a performance map has been obtained for gadolinium. The results, collected in terms of temperature span, coefficient of performance and mechanical power associated to circulation pump, lead to formulize viewpoints on employing magnetocaloric materials under optimized AMR working conditions