Improved packed-screen-type magnetocaloric element

Abstract

The invention relates to a magnetocaloric lattice element formed by fibres of magnetocaloric material, wherein the fibres are arranged in respective parallel lattice planes, each fibre having a respective mass of magnetocaloric material, the fibres of a given lattice plane do not contact each other but each fibre of a given lattice plane is attached to at least two fibres in a next neighbouring lattice plane, and wherein the magnetocaloric lattice element exhibits exactly one predominant mass-weighted direction of longitudinal fibre extension. When arranged in alignment of its predominant mass-weighted direction of longitudinal fibre extension with an external magnetic field, the magnetocaloric lattice element achieves an advantageous, particularly high magnetization of the magnetocaloric material, and as a consequence improves the performance of the magnetocaloric cooling device.

1 . A magnetocaloric lattice element comprising fibres of magnetocaloric material, wherein
 the fibres are arranged in lattice planes, which are parallel to each other, each fibre having a respective mass amount of magnetocaloric material,   the fibres of any given lattice plane do not contact each other but the fibres of the given lattice plane each contact at least two respective other fibres of a next neighbouring lattice plane, and wherein   the magnetocaloric lattice element exhibits exactly one predominant mass-weighted direction of longitudinal fibre extension.   
     
     
         2 . The magnetocaloric lattice element of  claim 1 , wherein, if each fibre is regarded as being partitioned into longitudinal fibre segments each having a segment mass and a longitudinal segment extension along a respective longitudinal segment direction, the predominant mass-weighted direction of longitudinal fibre extension is defined by the requirement that a weighted sum of all scalar projections of the respective longitudinal segment extensions of all fibre segments onto this predominant direction of longitudinal fibre extension is larger than the corresponding weighted sum of all scalar projections of the respective longitudinal segment extensions of all fibre segments onto any other direction of longitudinal segment extension, wherein each fibre segment is weighted in the weighted sum in proportion to its respective segment mass. 
     
     
         3 . The magnetocaloric lattice element according to  claim 1 , wherein all fibres belong to a first or second set of fibres and the fibres of the first set of fibres all extend along a common first longitudinal direction of fibre extension and the fibres of the second set of fibres all extend along a common second longitudinal direction of fibre extension different from the first longitudinal direction. 
     
     
         4 . The magnetocaloric lattice element according to  claim 3 , wherein a lattice angle between the first longitudinal direction and the second longitudinal direction is a sharp angle between 5° and 85°. 
     
     
         5 . The magnetocaloric lattice element according to  claim 3 , wherein the first set of fibres comprises a smaller mass amount of magnetocaloric material than the second set of fibres. 
     
     
         6 . The magnetocaloric lattice element according to  claim 5 , wherein a number of fibres in the first set of fibres is smaller than a number of fibres in the second set of fibres. 
     
     
         7 . The magnetocaloric lattice element according to  claim 5 , wherein, considering a cross-sectional surface area having a surface vector parallel to the longitudinal extension of the respective fibre segments, the first set of fibres is at least two times smaller than the second set of fibres. 
     
     
         8 . The magnetocaloric lattice element according to  claim 1 , wherein an extension of the fibres in a direction perpendicular to their longitudinal fibre extension is between 50 μm and 800 μm. 
     
     
         9 . A magnetocaloric regenerator, comprising
 a regenerator housing,   a magnetocaloric lattice element according to  claim 1  in the regenerator housing, and   a fluid channel system configured to guide a flow of a fluid through the magnetocaloric lattice element.   
     
     
         10 . A magnetocaloric heat pump, comprising
 a magnetocaloric lattice element according to  claim 1 , and further comprising   a magnet assembly for applying an external magnetic field to the magnetocaloric lattice element, wherein   the magnetocaloric lattice element and the magnet assembly are configured to be mutually arranged for applying the external magnetic field to the magnetocaloric lattice element with a field direction which is parallel to the predominant mass-weighted direction of longitudinal fibre extension.   
     
     
         11 . A magnetocaloric heat pump, comprising a magnetocaloric lattice element according to  claim 4 , and further comprising
 a magnet assembly for applying an external magnetic field to the magnetocaloric lattice element, wherein   the magnetocaloric lattice element and the magnet assembly are configured to be mutually arranged for applying the external magnetic field to the magnetocaloric lattice element with a field direction which is parallel to the predominant mass-weighted direction of longitudinal fibre extension,   wherein all fibres have a same respective mass amount of magnetocaloric material and wherein the magnetocaloric lattice element and the magnet assembly are configured to be mutually arranged for applying the external magnetic field to the magnetocaloric lattice element with a field direction which is oriented along a bisector of the sharp lattice angle between the first longitudinal direction and the second longitudinal direction.   
     
     
         12 . A magnetocaloric heat pump, comprising a magnetocaloric lattice element according to  claim 5 , and further comprising
 a magnet assembly for applying an external magnetic field to the magnetocaloric lattice element, wherein   the magnetocaloric lattice element and the magnet assembly are configured to be mutually arranged for applying the external magnetic field to the magnetocaloric lattice element with a field direction which is parallel to the predominant mass-weighted direction of longitudinal fibre extension,   wherein the first longitudinal direction is perpendicular to the second longitudinal direction and wherein the magnetocaloric lattice element and the magnet assembly are configured to be mutually arranged for applying the external magnetic field to the magnetocaloric lattice element with a field direction which is oriented along the second longitudinal direction which forms the predominant mass-weighted direction of longitudinal fibre extension.   
     
     
         13 . A cooling device, comprising a magnetocaloric lattice element according to  claim 1 . 
     
     
         14 . A magnetocaloric power generator, comprising a magnetocaloric lattice element according to  claim 1 . 
     
     
         15 . A method for operating a magnetocaloric heat pump, comprising:
 applying an external magnetic field to the magnetocaloric lattice element accordingly to  claim 1 ; and   arranging the magnetocaloric lattice element and a magnet assembly for applying the external magnetic field to the magnetocaloric lattice element with a field direction which is parallel to the predominant mass-weighted direction of longitudinal fibre extension.