Environmental Engineering Reference
In-Depth Information
s performance tests were carried out at an operating frequency of
4 Hz and the hot-side temperature was
The device
'
xed at 317 K. The zero-temperature span-
c cooling power was 2,001 W kg
−
1
, while at the temperature span of 12 K the
prototype could produce 1,375 W kg
−
1
, achieving COP = 1.6.
In 2005 researchers from George Washington University and the National
Institute of Standards and Technology presented a rotary magnetocaloric device in
the article by Shir et al. [
47
] (Table
7.15
). The AMR consisted of a Gd powder bed.
A 2 T permanent-magnet assembly was applied. The heat-transfer
speci
fl
uid was helium.
The gas
cylinder displacer. The maximum no-load
temperature span achieved was approximately 5 K.
Table
7.16
presents a magnetic prototype from General Electrics which was built
in 2012. It consists of two dual Halbach magnet assemblies for multistage AMR
beds testing. The heat-transfer
fl
ow was managed by a piston
-
fl
uid is controlled by linear piston pumping system.
7.2.2 Spanish Prototypes
The
rst Spanish rotary magnetic refrigeration prototype was built by the Poly-
technical University of Catalonia in collaboration with the Independent University
of Barcelona and the University of Barcelona. It was presented in 2000 by Bohigas
et al. [
48
]. A photograph of the prototype and some additional characteristics are
also presented in Table
7.17
.
The device comprised a rotating AMR disc and a stationary Nd
Fe
B magnet
-
-
assembly. The magnet assembly had one high-
eld area where 0.3 T of magnetic
eld could be induced. The AMR disc consisted of a plastic wheel with a Gd thin
ribbon attached to the wheel
s lateral surface. Two disc geometries were designed,
one with a diameter of 110 mm and the other with a diameter of 75 mm. Both discs
had a width of 0.8 mm. The magnetocaloric material was immersed in a container
'
uid.
The device could produce a no-load temperature span of 1.6 K at an operating
frequency of 0.33 Hz. In the next phase, the magnet assembly was improved, by
providing a magnetic
lled with olive oil as the heat-transfer
fl
eld of 0.95 T. After the improvement was made a no-load
temperature span of 5 K was achieved.
7.2.3 Japanese Prototypes
The
rst Japanese rotary magnetic prototype was built by the Tokyo Institute of
Technology in collaboration with Chubu Electric Power Co. Inc. and presented in
2005 at the First International Conference on Magnetic Refrigeration at Room
Temperature in Montreaux, Switzerland by Okamura et al. [
49
]. The prototype
consisted of four AMR beds and a rotating Nd
Fe
B magnet assembly. The magnet
-
-
assembly had two high-
eld areas (0.77 T) that were rotating over the four AMR beds.
Search WWH ::
Custom Search