Environmental Engineering Reference
In-Depth Information
Fig. 8.14 An opened magnet assembly of a rotary magnetocaloric device with the azimuth
fl
uid
fl
ow through AMRs, classication no: R20(3)0(5)(6)01111(12)
for the case when the AMR is in transition from the high-
eld
region and vice versa. Furthermore the discontinuous rotation would certainly lead
to better performance of a device.
In a rotating disc with AMRs and with the azimuth
eld to the low-
uid,
usually a central valve system will serve for the switching and the distribution of the
fl
fl
ow of the working
fl
uid. In Fig. 8.14 (right), a simple example is shown, where we denote using the
Roman numbers from I to VIII the particular process with regard to the
ow.
The case of Fig. 8.14 (right) shows the application of the uni-directional pump I,
which pumps the
fl
uid
fl
fl
uid through the HHEX. There the
fl
uid rejects the heat to the
environment and
uid
is redirected to two AMRs being in the demagnetized state III. When the working
fl
fl
ows further to the valve-distribution system. From this the
fl
uid passes the demagnetized AMRs, it cools down IV and then re-enters the valve
system in which it is redistributed again to V. However, this time it
ows toward
the CHEX, where it absorbs heat VI from the refrigerated environment. The
working
fl
ows back to the valve system, which guides it now towards the
AMRs in the magnetized state VII. By passing the magnetized AMRs the working
fl
fl
uid
fl
uid heats up VIII and continues the
ow to the valve system.
In Fig. 8.15 a, the AMRs are shaped as rectangular inserts. This simpli
fl
es their
production. However, one should take care of the magnetic
ux density distribution
in such AMRs. In Fig. 8.15 b another example is shown in which the AMR consists
of parallel discs, whose shape is reminiscent of a Tesla turbine (magnets are
positioned below and above such discs
fl
in Fig. 8.15 b only the lower part of
magnet assembly is shown). This kind of arrangement looks interesting. However,
there is the question of a suf
cient heat-transfer surface provided by the magnet-
ocaloric material.
Also in azimuth
ow devices, as this holds for axial and radial devices, the
number of poles (high magnetic
fl
uid-
fl
eld regions) can vary. Therefore, a similar
example as that shown in Figs. 8.10 and 8.11 can be applied for azimuth devices as
well.
Search WWH ::




Custom Search