Improvements of a room-temperature magnetic refrigerator combined with Stirling cycle refrigeration effect

• Published in: International journal of refrigeration 2016-07, Vol.67, p.330-335
• Main Authors: Gao, X.Q., Shen, J., He, X.N., Tang, C.C., Li, K., Dai, W., Li, Z.X., Jia, J.C., Gong, M.Q., Wu, J.F.
• Format: Article
• Language: English
• Subjects: Angle de phase; Cooling performance; Froid magnétique; Froid à cycle de Stirling; Hybrid refrigerator; Magnetic refrigeration; Performance de refroidissement; Phase angle; Réfrigérateur hybride; Stirling cycle refrigeration
• ISSN: 0140-7007; 1879-2081
• DOI: 10.1016/j.ijrefrig.2016.02.021

•A high pressure hybrid magnetic refrigerator combined with Stirling refrigeration was designed.•A centric Halbach cylinder permanent magnet was used in the hybrid machine.•An optimal phase angle of this hybrid system was figured out.•The cooling powers improved by 28.5% in the hybrid machine. A high pressure hybrid refrigerator that combines the active magnetic refrigeration effect with the Stirling cycle refrigeration effect at room temperature is studied here. In the apparatus, a helium-gas-filled alfa-type Stirling refrigerator uses Gd sheets as the regenerator and the regenerator is put in a magnetic field varying from 0 to 1.4 T, which is provided by a Halbach-type rotary permanent magnet assembly. With an operating pressure of 5.5 MPa and a frequency of 2.5 Hz, a no-load temperature of 273.8 K was reached in 9 minutes, which is lower than that of 277.6 K for pure Stirling cycle. For the hybrid operation, cooling powers of 40.3 W and 56.4 W were achieved over temperature spans of 15 K and 12 K, respectively. For the latter case, the cooling power improves by 28.5% if compared with that exploiting only the Stirling cycle refrigeration effect.