Overview of Existing Magnetocaloric Prototype Devices - Magnetocaloric Energy Conversion: From Theory to Applications - page 299

Table 7.18 Second rotary prototype from Tokyo Institute of Technology and Chubu Electric
Power Co. Inc
Name and address of institute Chubu Electric Power Co., Inc.

Name of contact person/email Naoki Hirano/[e-mail]

Year of production 2007

Type Rotary

Maximum frequency 1 Hz

Maximum cooling power 540 W

Maximum temperature span 20 K

Type of AMR Packed bed

MC material(s) Gd and Gd alloys

Type of magnets Permanent, 1.1 T

the yoke caused by eddy currents via the magnet rotation. Furthermore, the magnets
were replaced by stronger ones to induce a higher magnetic eld of 1.1 T. Also, the

AMR duct con gurations were changed along with the piping diameter to increase

the ow rate and decrease the pressure drop.

The four AMR beds were

fl

lled with 4,000 g of Gd spheres with a diameter of
0.5 mm. The operating frequency was set to 1 Hz and the hot-side temperature to
294 K. At a temperature span of 5.2 K, the device could produce 37.5 W kg − 1 of
speci c cooling power with a COP of 0.5, while at 0.2 K of temperature span the

specic cooling power was 135 W kg − 1 and the COP was 1.8.
Tables 7.19 , 7.20 , 7.21 and 7.22 present the operating characteristics and pic-
tures of four additional Japanese rotary magnetic refrigeration prototypes built
between years 2009 and 2013 at Hokkaido Research Institute, Kobe University,
Railway Technical Research Institute and Sanden Co. Inc., respectively.
The prototype from Hokkaido Research Institute (Table 7.19 ) achieved a max-
imum cooling power of 150 W and a maximum temperature span of 5.5 K.
The prototype from Kobe University (Table 7.20 ) could achieve a maximum
temperature span of 5 K and a maximum cooling power of 10 W. The magnet
assembly consisted of permanent magnets that could induce a magnetic eld of 0.6 T.

The device built at the Railway Technical Research Institute (Table 7.21 ) con-
sisted of a Nd B Halbach magnet assembly and could achieve a maximum

temperature span 7.6 K, while the maximum cooling power was 150 W.
The prototype built at the Sanden Co. Inc. (Table 7.22 ) was composed of a per-
manent-magnet assembly that could induce a magnetic

Fe

- -

eld of 0.85 T. The maximum

c cooling power was 157.1 W kg − 1 . temperature span was 13.8 K, while the speci

7.2.4 Swiss Prototypes

The rst Swiss rotary magnetic refrigeration prototype was built at the University of

Applied Sciences of Western Switzerland and presented in 2006 [ 51 ]. The prototype
was built as a rotary magnetic demonstrator for air conditioning. The device