526 Watt/cm³? How should I interpret that? I doubt it’s by the volume of the stuff covered with the film; it seems way too high for that (that would freeze water in seconds, if I’m not mistaken)
The best I can think of is that it is by the volume of the film, but I find that a weird way to express it, as it would seem to imply there’s little difference between a thin film over a large area and a thicker one over a smaller one.
But let’s go with that. Assuming a film thickness of 100nm (article says “50-100nm thick”) = 10^-7m = 10^-5cm, one would ⁿ eed an area of 10⁵ cm² = 10 m² to get that 526 Watt of power out. Still seems high. If that’s how to interpret that number, what kind of stuff do I need to cover with this film for that to happen?
That is for the volume of the film, yes: (via scihub)
"PMN–0.32PT thin films
are shown to provide record-breaking pyroelectric energy con
-
version, including: first, the largest energy density of 1.06
J cm
−
3
(at
Δ
T
=
90 K,
Δ
E
=
267 kV cm
−
1
and
f
=
40 Hz; Fig.
4a), which is
made possible because of the large field-induced value of
π
and
the ability to apply large electric fields maximizing the electrical
work (
∮
⋅
EP
d
). Second, the largest power density of 526
Wcm
−
3
(at
Δ
T
=
56 K,
Δ
E
=
267 kV cm
−
1
and
f
=
1,000 Hz; Fig.
4b) that is real
-
ized because the power density scales directly with cycling fre
-
quency, which can be increased because the thermal time constant
of the thin-film geometry is small."
Note the operational constraints. You have to apply a varying electic field and a varying temperature.
The Carnot limit applies specifically to heat engines but later proofs on the 2nd law of thermodynamics still cap the conversion of heat to useful energy. As long as you keep that in mind, 19% Carnot efficiency is really impressive for a system like this with a small temp difference and no moving parts. I find their watts per cubic region an odd way to measure it given that you need heat flow across a surface to generate juice.
IANA thermodynamicist, but I suspect the resulting system could not be more efficient than either the heat pump or the pyroelectric charge pump by itself. So if this conversion process is really that great, you would end up replacing your heat pump with it instead of combining them.
I think this only applies if we're constraining the temperatures to typical summer outdoor/indoor cooling applications. Different technologies are going to have different temperature ranges at which they are most efficient, so for something like steam power generation multi-stage systems are common.
The hood is exactly the wrong place. Blocks, radiators, even oil pans would be far better.
But imho the real market for these will be in low-power environments. Or defense: submarines have near-unlimited heatsink potential and lots of <100 heat sources.
[+] [-] Someone|8 years ago|reply
The best I can think of is that it is by the volume of the film, but I find that a weird way to express it, as it would seem to imply there’s little difference between a thin film over a large area and a thicker one over a smaller one.
But let’s go with that. Assuming a film thickness of 100nm (article says “50-100nm thick”) = 10^-7m = 10^-5cm, one would ⁿ eed an area of 10⁵ cm² = 10 m² to get that 526 Watt of power out. Still seems high. If that’s how to interpret that number, what kind of stuff do I need to cover with this film for that to happen?
[+] [-] pjc50|8 years ago|reply
"PMN–0.32PT thin films are shown to provide record-breaking pyroelectric energy con - version, including: first, the largest energy density of 1.06 J cm − 3 (at Δ T = 90 K, Δ E = 267 kV cm − 1 and f = 40 Hz; Fig. 4a), which is made possible because of the large field-induced value of π and the ability to apply large electric fields maximizing the electrical work ( ∮ ⋅ EP d ). Second, the largest power density of 526 Wcm − 3 (at Δ T = 56 K, Δ E = 267 kV cm − 1 and f = 1,000 Hz; Fig. 4b) that is real - ized because the power density scales directly with cycling fre - quency, which can be increased because the thermal time constant of the thin-film geometry is small."
Note the operational constraints. You have to apply a varying electic field and a varying temperature.
[+] [-] trumped|8 years ago|reply
[+] [-] boxcardavin|8 years ago|reply
[+] [-] pjc50|8 years ago|reply
[+] [-] hinkley|8 years ago|reply
I wonder when someone will add pyroelectric film to something to make it more resistant to thermal shock?
[+] [-] 21|8 years ago|reply
[+] [-] marshray|8 years ago|reply
I think this only applies if we're constraining the temperatures to typical summer outdoor/indoor cooling applications. Different technologies are going to have different temperature ranges at which they are most efficient, so for something like steam power generation multi-stage systems are common.
[+] [-] mark-r|8 years ago|reply
[+] [-] pjc50|8 years ago|reply
[+] [-] agumonkey|8 years ago|reply
[+] [-] sandworm101|8 years ago|reply
But imho the real market for these will be in low-power environments. Or defense: submarines have near-unlimited heatsink potential and lots of <100 heat sources.
[+] [-] sschueller|8 years ago|reply
[+] [-] starpilot|8 years ago|reply
[+] [-] toblender|8 years ago|reply
[+] [-] myfonj|8 years ago|reply
[+] [-] marshray|8 years ago|reply
Energy per volume?
That would make sense for, say, battery storage but can anyone explain how it describes an energy conversion process?