Heat pump and cascaded caloric regenerator assembly

A refrigerator appliance, comprising:

• a cabinet defining a chilled chamber;
• and
• a heat pump system operable to cool the chilled chamber, the heat pump system comprising
• a cold side heat exchanger positioned at the chilled chamber;
• a hot side heat exchanger positioned outside the chilled chamber;
• a pump operable to flow a working fluid between the hot and cold side heat exchangers;
• and
• a caloric heat pump comprising:
• a regenerator housing extending along an axial direction between a first end portion of the regenerator housing and a second end portion of the regenerator housing, the regenerator housing defining a chamber that extends longitudinally along the axial direction between the first and second end portions of the regenerator housing,
• a plurality of stages positioned within the regenerator housing, the plurality of stages being arranged sequentially along the axial direction from the first end portion to the second end portion, each stage of the plurality of stages comprising a caloric material having a caloric temperature peak, the plurality of stages being arranged so that the caloric temperature peaks of the plurality of stages increase along the axial direction according to a predetermined, consistent, non-linear curve, and
• a field generator positioned adjacent to the plurality of stages to subject the plurality of stages to a variable field generated by the field generator,
• wherein the predetermined, consistent, non-linear curve defines a curvature ratio between −0.5 and 0.5 defined from the first end portion to the second end portion.