Magnetocaloric Fluids - Magnetocaloric Energy Conversion: From Theory to Applications - page 190

5.4 Review of Research on Magnetocaloric Fluids

The earliest work performed in the eld of magnetocaloric energy conversion for

the application of magnetocaloric uids can be found in Resler and Rosensweig

[ 150 , 151 ], who published their articles in 1964 and 1967, respectively. In 1969,
another study was conducted by Van der Voort [ 152 ]. In 1985, Rosensweig [ 7 ]
published a topic on ferrohydrodynamics, which in a large part dealt also with the
magnetocaloric energy conversion using ferrofluids. This work can actually be
considered as the basis for the study of magnetic

fl

fl uids, including those that may be

applied in magnetocaloric energy conversion.
From 1993, an idea to perform heating and cooling based on magnetocaloric

fl uids can be found in the patent of Burnett [ 153 ]. In 1996, Shao [ 154 ] published

work on the preparation of magnetocaloric nano

uids for room-temperature mag-
netic refrigeration. Later in 2003, also Shir et al. [ 155 ] reported on the research and
production of magnetic nanocomposites that could consist of a solid phase in a
nano

fl

uid.
Since then, a number of publications can be found concerning magnetocaloric

fl

fl uids; however, there is no evidence that these magnetocaloric fl uids have been

applied in refrigeration, heat pumping or power generation.
On the other hand, this domain is still developing, and magnetocaloric uids are

the subject of research efforts for different applications. For instance, today

fl

s well-
known hyperthermia cancer treatment (still in the phase of trials), which applies the
hysteresis effect of particles in ferro

'

eld
(see, e.g. Jordan et al. [ 156 ], Hiergeist et al. [ 157 ], Rosensweig [ 158 ]), was
upgraded by the idea of Prof. Tishin [ 159 ] (see also Tishin et al. [ 160 ]), who
proposed the use of the magnetocaloric effect to enhance the heating of cancer cells
by applying a variable magnetic

fl uids induced by alternating magnetic

eld. In this case, the magnetocaloric particle
would act as the nano-heat pump, providing the required heat to destroy the cancer
cells. Later, the idea of drug release based on the magnetocaloric effect was
investigated by Li et al. [ 161 ].
The majority of articles that are related to the use of magnetocaloric

uids are
related to propulsion (pump) systems, and the majority of them regard the (self)
heat-driven thermal management systems.

fl

5.4.1 Magnetocaloric Fluid Propulsion

We rst present the basic principle of magnetocaloric pumping, which was

described by Rosensweig [ 7 ], by developing the ferrohydrodynamic Bernoulli
equation. Figure 5.5 shows an element of the magnetic

fl uid with the mass ˁ∙ a ∙ ds in

the gradient of the magnetic uid moves with a velocity v along the

distance s, and with the height h over the reference ground level. Rosensweig [ 7 ]
proposed the following generalized Bernoulli equation:

eld. The fl