Environmental Engineering Reference
In-Depth Information
material being 0.1 US$(Wcooling)
−
1
for a frequency of operation of 10 Hz. For the
case of Gd, but in this case the evaluation was focused on Nd
2
Fe
14
B-type per-
manent magnets (1.4 T) with a cost of 27 US$kg
−
1
, the speci
c cost of such a
magnet assembly would be 10.2 US$(Wcooling)
−
1
. In the case of La(Fe
1-x
Si
x
)
13
material, this would lead to the speci
c cost of the magnet assembly being 2.2 US
$(Wcooling)
−
1
. No analyses of the operating characteristics and ef
ciency of the
magnetic air conditioner were performed.
Most of the comprehensive technical economic analyses on magnetic refriger-
ation, magnetic heat pumping and magnetic power generation were performed by
the group from the University of Applied Sciences of Western Switzerland
(USAWS), who did several different studies for the Swiss Federal Of
ce of Energy
in the period 2004
29
]).
Note that these studies can be accessed free on the website of the Swiss Federal
Of
2010 (these can be found in the following references [
25
-
-
ce of Energy. In the subsequent text we present some of the most important
ndings of these studies.
In 2006, a feasibility study on magnetic heat pumps was published by Egolf
et al. [
25
]. The authors did a technical-economic analyses for an 8-kW, ground-
source, rotary magnetic heat pump with the temperature of the heat source and the
heat sink (on the water side) being 0 and 35
°
C, respectively. The aim of the
analysis was to compare such a heat pump with a conventional compressor-based
heat pump for the same efciency COP = 6.5 and for the same operating
parameters.
For this purpose the following material costs and masses were estimated (see
also Fig.
9.10
):
magnetocaloric material (125 eurokg
−
1
)
permanent magnet material (60 eurokg
−
1
)
soft iron (45 eurokg
−
1
)
other material costs (10 eurokg
−
1
)
Fig. 9.10 Masses depending
on the frequency of the
operation (data taken from
Egolf et al. [
25
])
Search WWH ::
Custom Search