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mechanisms provides heat regeneration along the magnetocaloric material (parallel
to the axis of the rotation).
This is why we refer to such a system as an AMR with the application of the
thermal diode mechanism. We encourage the research community to seriously
consider this kind of solution for future developments of the magnetocaloric energy
vided suf
cient information, which may serve as the basis for such developments.
8.5 Devices with Magnetocaloric Fluids
The idea of applying magnetocaloric
uids as the refrigerant is certainly very
attractive. The architectures of devices that can be applied in this particular case can
be found in the chapter on magnetocaloric
fl
fl
uids. However, the major obstacle of
magnetocaloric
fl
uids is in the content of the magnetocaloric material in base
(nano
fl
uids
--
ferro
fl
uids) or the carrier
fl
uid (magnetocaloric particle suspensions).
In the
rst, the thermal mass of the magnetocaloric material is relatively low
compared to the base
fl
uid. Therefore, the effective adiabatic temperature change of
the magnetocaloric
uid will be very low. If one accounts for irreversible heat
transfer that is associated with the temperature difference, then it becomes clear that
such devices, unless a very high magnetic
fl
eld is applied, will not represent a
solution for refrigeration, heat pumping, air-conditioning or power generation.
Other solution for ef
cient magnetocaloric ferro
fl
uids regards the application of
liquid metals as base
uids.
If, on the other hand, the magnetocaloric particle suspension is applied (magnet-
ocaloricmagnetorheological
fl
uid), this will be associatedwith highly non-Newtonian
rheological behaviour, which does not depend only on the particle size and their
volume fraction, but also on the magnetic
fl
eld and associated with the yield stress.
uids can be successfully applied in thermal management as
self-running systems (similar to heat pipes). If they are applied for refrigeration,
heat pumping or power generation, rather high magnetic
Magnetocaloric
fl
eld will be required.
uids have a good potential to be applied in
magnetocaloric devices with solid magnetocaloric material. They can be used in
valve system, or as the actuator in a special pump system. These
Note that magnetorheological
fl
uids can be also
successfully applied as dynamic seals. Moreover, magnetorheologic
fl
fl
uids can
serve as thermal diode mechanisms.
The authors ask the reader to see the chapter on magnetocaloric
There we show design concepts for magnetocaloric energy conversion with mag-
netocaloric
fl
fl
uids. Moreover, different potential applications of magnetic
fl
uids in
the magnetocaloric energy conversion are discussed.
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