A Novel Permanent Magnet System for Magnetic Refrigerator and its Magnetic Field Analysis

This paper presents a novel configuration of the permanent magnet system for rotating magnetic refrigerator, which consists of stator and rotor. The stator of this system includes two permanent magnets and iron yoke. The rotor includes shaft, iron core and magnetic refrigerant material. When the magnetic refrigerant material is located under the pole of the permanent magnet, it is magnetized by a strong magnetic field and has a high temperature. As the rotor rotates, the magnetic refrigerant material is continuously demagnetized and its temperature gets lower and lower. When the rotor has turned 90°space angle, the magnetic refrigerant material lies in the smallest magnetic field and its temperature becomes minimal. With the rotation of the permanent magnet system rotor, the magnetic refrigerant material is periodically magnetized and demagnetized and produces the magnetic thermal power for magnetic refrigeration. The permanent magnet system can generate the magnetic field of up to 1.2 T. It is much stronger than that generated by the two permanent magnets placed parallel to each other. Compared with the existing ones, this permanent magnet system has the advantages of high magnetic field strength, small size, simple structure, compact, high operation reliability, no one-side magnetic pull on the rotor and small vibration and noise, etc.