Magnetocaloric Fluids - Magnetocaloric Energy Conversion: From Theory to Applications - page 193

uid for
thermal management. The same year, experimental research on the application of
propulsion and thermal management with the ferro

In 2009, Fumoto et al. [ 165 ] investigated the use of a magnetocaloric fl

uid was performed by Lian and
Xuan [ 166 ] and reported later also in 2011 [ 167 ], where they simulated chip cooling
with such an application.
In 2010, Pal et al. [ 168 ] did experimental research on a ferro

fl

uid-based
pump. For this purpose, a table-top version of thermomagnetic pump was con-
structed and its performance was experimentally evaluated for two different types of
ferro

fl

uids. The authors emphasized that thermomagnetic pumps are basically low-
head high-heat-

fl

ux discharge devices (see also Pal et al. [ 169 ]).
In 2010, Kitanovski and Egolf [ 170 ] described and showed an idea for applying
a magnetocaloric

fl

uid for cooling the concentrated photovoltaic system.
In 2011, Xia et al. [ 171 ] reported on a theoretical study of a micro-pump based
on the magnetocaloric effect of a magnetic

fl

uid. A number of different concepts for
applying ferrohydrodynamic micro-pump systems were presented by Nguyen [ 172 ]
in 2012, including magnetocaloric

fl

uids.
In 2014, Petit et al. [ 173 ] reported on an experimental investigation of a ferro-

fl

fl uid (based on MnZn) pump for thermal management. They pointed out that the

results from the scienti c literature generally conclude that the experimental static

pressure is lower than the theoretical one. A conclusion has been made according to
the author ' s observations, that the magnetostatic pressure is limited due to magneto-
convective motion of the ferro fl uid, which causes a decrease in the temperature

gradient in the ferro uid. A further reduction in the pressure was assumed to be due

to the agglomeration of magnetic particles.

fl

5.4.2 Refrigeration and Heat Pumping by the Application
of a Magnetocaloric Fluid

Following earlier research described at the beginning of this chapter, in the past
decade there were a small number of research activities performed in the eld of

magnetic refrigeration and heat pumping concerning the magnetocaloric fl uids.

rst such study was published by Rosensweig in 2006 [ 15 ], who investi-
gated the room-temperature refrigeration with magnetocaloric suspensions by the
application of a permanent magnetic

The

eld source (Fig. 5.6 ). As the author pointed
out, the advantage of applying this kind of system (which includes regenerative heat
transfer) over systems with solid magnetocaloric materials avoids wear, drag and
leakage problems from mechanical sliding seals.
In the theoretical study [ 15 ], the regenerative refrigeration Brayton cycle was
investigated for the system providing 100 W of cooling and operating between the
heat-source temperature of 273 K and the heat-sink temperature of 298 K. Amodi ed

Halbach permanent-magnet array has been proposed as the magnetic eld source with

a high magnetic flux density of 3 T. The working medium evaluated in the study of