Environmental Engineering Reference
In-Depth Information
Table 10.10 Results of the dipping experiment
Material
d
a
(
µ
m)
Material type
T
low
(
°
C)
T
high
(
°
C)
E
low
(MVm
−
1
)
E
high
(MVm
−
1
)
Work per
cycle (JL
−
1
)
References
P(VDF-TrFE) 60/40
Polymer
50
100
6.7
27.6
165
25 [
60
]
P(VDF-TrFE) 60/40
Polymer
55
100
6.7
20
95
25 [
60
]
P(VDF-TrFE) 60/40
Polymer
55
100
6.7
20
70
25 [
60
]
PLZT 9/65/35
Bulk ceramic
3
150
0.4
7.5
654
200 [
61
]
PLZT 8/65/35
Bulk ceramic
25
160
0.2
7.5
888
290 [
61
]
PLZT 7/65/35
Bulk ceramic
30
200
0.2
7
1,014
190 [
61
]
PLZT 6/65/35
Bulk ceramic
40
210
0.4
8.5
949
180 [
61
]
PLZT 5/65/35
Bulk ceramic
40
250
0.4
7.5
799
200 [
61
]
0.9Pb(Mg
1/3
Nb
2/3
)O
3
-
0.1PbTiO
3
Bulk ceramic
30
80
0
3.5
186
1,000 [
77
]
Pb(Zn
1/3
Nb
2/
3
)
0.95
Ti
0.4
O
3
Single-crystal
ceramic
100
160
0
2
243
1,000 [
78
]
68PbMg
1/3
Nb
2/
3
O
3
-
3
2PbTiO
3
Single-crystal
ceramic
80
170
2
9
100
140 [
79
]
0.945PbZn
1/3
Nb
2/3
O
3
-
0.055 PbTiO
3
Single-crystal
ceramic
100
190
0
1.2
150
200 [
72
]
a
d is the thickness of the pyroelectric material
values of the electrical energy generated per cycle reported by the authors are
presented. In general, the electrical energy generated is a function of the temper-
ature difference between the hot and the cold thermal bath and the difference
between the applied electrical
elds. It is clear that the higher the temperature
change of the pyroelectric material and the larger the electric
eld change [
61
,
76
],
the larger will be the amount of generated electrical energy. However, other effects,
such as the current leakage, can have a signi
cant impact on the electrical energy
generated in such processes [
4
].
However, the experimental setups for performing the dipping experiment cannot
be considered as real pyroelectric energy harvesting devices. The sample is, in most
cases, manually moved from the hot to the cold thermal bath and the frequencies of
the operation are relatively low. For example, Lee et al. [
61
] reported that the
pyroelectric material was moved from the hot thermal bath to the cold thermal bath
every 15
25 s. Nevertheless, the results of the dipping experiment give important
information about the pyroelectric material itself.
Cha et al. [
80
] presented a pyroelectric energy harvesting device that uses liquid-
based thermal interfaces and operates under a pyroelectric Ericsson cycle. No
regeneration process was employed and the pyroelectric material was subjected
to the same thermodynamic cycle as in the case of the dipping experiments.
However, the fre quency of the device reached 1 Hz and it worked autonomously.
Therefore, the device is not considered as an experiment, the aim of which is to
de
-
ne the maximum energy produced in the pyroelectric element per single ther-
modynamic cycle (as in the case of the dipping experiment), but rather as a pro-
totype energy conversion device. The device is schematically presented in
Fig.
10.21
. In the centre of the device was a 5-
µ
m-thick P(VDF-TrFE) 56/44
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