
New multiferroic alloy turns waste heat into green electricity for free - mrseb
http://www.extremetech.com/extreme/87680-new-alloy-turns-waste-heat-into-electricity-for-free
======
DanielBMarkham
I don't want to play grumpy old guy, but I'm getting a bit tired of breathless
articles that omit key facts.

What's the efficiency? It's such an obvious question I can't imagine writing
an article without that data. How about current costs of other green power?
Difficultly of the subject area? Others who have tried?

I love these new tech stories, but one or two paragraphs of context can go a
long way for the reader. We're left having the same old discussion: one person
says "awesome!" and then another points out one of these obvious (and common)
holes. It's the same discussion, over and over again.

It's not just the energy stories. I've seen dozens of startup stories that are
long on hype and emotion and really short on explaining the market and how the
company is executing -- the key things that any other startup person would
want to know. Heck, I know everybody's excited about it, what I want is
somebody giving me a bit of perspective.

Same goes for "new cancer treatment found!" articles, which are also long on
emotion and short on context. I know emotion gets clicks, just wish we could
do better here.

~~~
mrseb
Hi, author here.

I agree, there is a lot more that tech blogs could do to help the reader. The
problem is, that kind of extra detail isn't really possible without
specializing -- and if you specialize, you limit the size of your audience.

The other problem is writing the stories: it would be awesome to have a writer
for every kind of topic, so that every story can be tackled with complete
background knowledge... but that's just not feasible. Instead, most tech blogs
have writers with 'beats' that they cover -- but even then, if the 'green
technologies' writer is out for the day, someone else has to tackle it.

So for the most part, we tech bloggers just try to get a good grasp of the
technology, and then boil it down into a form that's easy to read and
understand. The resultant story quality is variable and depends a lot on how
much time and effort you put into it, and your background knowledge -- but I
like to think I do a fairly good job :)

~~~
jerf
The objections DanielBMarkham are raising are literally high-school physics
issues. I'm not expecting a QM explanation of what's going on, at this stage
the researchers may not even be totally clear, but we know the efficiency is
going to be bounded by thermodynamics, and in particular "generating
electricity from waste heat!" rates dangerously high on the Science Bullshit-
O-Meter. It can be done, but the bounds on efficiency are pretty dismal.

I'm not asking for a physics PhD level of coverage, but if you're going to
cover this sort of thing giving us at least a high-school level of coverage
would be nice. Just segment it off so those who are somehow interested in this
but lack even that low bar of knowledge don't get too confused.

... or... not. I honestly can't say with a straight face this would increase
your reader count, or any other interesting metric like that.

~~~
eru
While it may not increase your reader count in the short run, it will probably
make your readers come back, and let the article stay relevant for longer.

------
quasistar
In materials science labs around the world, researchers are performing
'miracles'.

Aerogels could eliminate most of the waste heat from buildings. Piezoelectric
nanogenerators could power mobile electronic devices. Graphene transistors
could attain speeds of 1THz. And multiferroics like the beastly
Ni45Co5Mn40Sn10 mentioned above could replace bulky laptop batteries.

But what is achieved with multi-million dollar government sponsored research
grants in controlled labs is difficult to transfer to ones doorstep.

One barrier is economic: an aerogel house would cost $50M! A pricetag that may
be acceptable to the Department of Defense, but won't do Peoria Joe much good.

------
SigmundA
The whole article acts like we have never discovered thermocouples:
<http://en.wikipedia.org/wiki/Thermocouple>

I mean the voyager spacecraft are powered by them:
[http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_gen...](http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator)

Along with many gas appliances with pilot lights.

~~~
sliverstorm
It could get away with pretending we hadn't- if the efficiency was leaps and
bounds greater.

Or rather, if they even bothered to comment on efficiency at all.

------
khafra
Basically the same as a seebeck generator; but it can be used in places where
current seebeck generators would not do well.

I wish they would phrase these things as "turns heat differences into
electricity;" because every time they say "waste heat," people get excited
about harvesting heat from their CPU and having their computer power itself.

~~~
dspillett
Well _in theory_ a proportion of the heat generated by a hot running CPU or
GPU (or anything else that operates at a temperature significantly higher than
the local ambient temperature) could be converted to useful energy, and you
could feed the generated power back into the unit to reduce what it needs to
sink from other sources.

Though of course you would have to work out if the energy savings are enough
to outweigh the extra energy used in manufacturing such a device (remembering
to account for the fact that the extra complexity of each unit may reduce the
effective yield of the manufacturing process). It might cost far more energy
to make than it'll ever save in its active life. Thermodynamics can be a
bugger like that...

~~~
chadgeidel
I'm going to play a bit of "devil's advocate" here. :-) The general problem of
place-shifting and time-shifting energy (wind power / solar power) is a very
real issue and you could make tons of money solving it.

This particular application won't of course.

------
trebor
If I remember correctly, there was recent talk about the magnetic component of
light being much strong than thought. Well, why not focus light on this
material and let the _heat_ make a stronger magnetic field and use it as a
solar panel?

~~~
ars
Because you need a cold sink to make this work. Solar panels need a dark sink,
but that's easy to get.

You can only convert energy (i.e. do work) when sending energy from high to
low, for example hot to cold, light to dark, etc. (If you heated a solar panel
to the point that it glowed with the same intensity as the incoming light it
would not work. Ignoring the fact that it would melt :)

Electric power plants use bodies of water as the cold sink. If you ever see
clouds of what looks like smoke, but is really steam while driving, what you
are seeing is the cold water evaporating after being used as a cold sink.

BTW if you did want a solar-thermal power plant they exist, and don't need
this material. It's a lot simpler than that - just concentrate the light to
heat water and run a steam turbine.

BTW#2 "the magnetic component of light being much strong than thought" doesn't
make sense. The magnetic component of light is VERY well understood. You are
probably misremembering, or misunderstanding.

~~~
trebor
See the other comment for the article/premise I referred to. I'm not a
scientist, just a programmer trying to figure out if this'd work.

The article stated that the magnetism of light is 100 million times more
powerful than previously thought. But, that it must be focused to 10 million
watts per cm^2. The premise is that the light induces magnetism that can be
drawn as power. Supposedly it requires special materials.

But, if you drew the sun's rays to focus on this material to provide heat
couldn't it produce a similar use?

------
radu_floricica
I'm guessing its applications would be more in the line of powering remote
devices then anything more substantial. I could see the point of replacing a
photovoltaic panel with a hunk of metal in a seismic sensor or something like
that.

------
jcr
One application of the alloy is automotive, but there is other work being done
in this space:

<http://news.ycombinator.com/item?id=2687439>

------
georgieporgie
I don't get it. So you can use heat to make a magnet. We already have
permanent magnets. Magnetism, in and of itself, doesn't create energy. You'd
have to either pulse the magnet, or move a coil past the magnet. The former
seems impossible since you'd have to cycle its temperature, and the latter
just gives you an alternator, which we already have.

If I'm missing something, I'd like to know. It just looks like, "hey,
magnetism!" and some hand-waving.

------
vineel
This looks like it has the possibility to dramatically increase the efficiency
of motors and engines.

Also, if they could capture the heat coming out of a nuclear reactor, they
could both avoid meltdowns and not require proximity to a large body of water.

Edit: Disregard this. I don't know thermodynamics as well as I thought I did.

~~~
StavrosK
If by "dramatically" you mean "by 0.004%", then yes.

More information:

[http://www.reddit.com/r/science/comments/i6pfi/new_alloy_can...](http://www.reddit.com/r/science/comments/i6pfi/new_alloy_can_convert_heat_directly_into/)

~~~
vineel
I may have been too optimistic. But 30% is still quite a bit.

Modern gasoline engines have an average efficiency of 20%. Say you put 100J
into one. 20J of useful work will be produced, and 80J of heat. Now if 30% of
that heat were captured, that's another 24J of useful work. In effect, we've
doubled the engine's efficiency from 20% to 44%. That's pretty dramatic.

~~~
StavrosK
Hmm, where are you getting 30% from? The paper says 0.004%, if I understand it
correctly.

~~~
vineel
This comment:
[http://www.reddit.com/r/science/comments/i6pfi/new_alloy_can...](http://www.reddit.com/r/science/comments/i6pfi/new_alloy_can_convert_heat_directly_into/c21cizq)

Which says that the efficiency could reach 30% with some work. I assume that
%30 is not a typo.

~~~
StavrosK
Oh, I think 30% is the theoretical maximum. He says they can reach 3% with
years of work. It would be great if they could achieve 30%, but I doubt it.

------
asciilifeform
Epic thermodynamics fail:

<http://en.wikipedia.org/wiki/Carnot_efficiency#Efficiency>

~~~
ugh
Not really. (Also: “Epic fail” and a pretty cryptic and lazy link? Doesn’t
seem HN worthy.) This obviously doesn’t make perpetual motion machines a
possibility and the article reeks of hyperbole but this technology is
potentially useful.

It would be better to just make stuff that doesn’t produce any waste heat, I
guess you could say that this is sort of a step in that direction. It’s for
making stuff more efficient, no more, no less.

~~~
asciilifeform
_> a pretty cryptic and lazy link? Doesn’t seem HN worthy_

If you know of a better intro that I can link to, please post it.

 _> This obviously doesn’t make perpetual motion machines a possibility_

As if perpetual motion were the only thing forbidden by the laws of
thermodynamics.

 _> this technology is potentially useful._

To those pushing it. To everyone else, it is a scam, plain and simple.

 _> It would be better to just make stuff that doesn’t produce any waste heat_

Please, please open a physics textbook. I beg of you.

~~~
hugh3
* Please, please open a physics textbook. I beg of you.*

Even better, I'll go ask a physicist.

Ooh, I'm a physicist!

Hey hugh3, does this violate the second law of thermodynamics?

Uhh, nope, not at all! You can always extract some useful work when
transferring heat from a hot bath to a cold bath.

Gee, thanks hugh3!

~~~
asciilifeform
_> You can always extract some useful work when transferring heat from a hot
bath to a cold bath._

True. But this is Jesuitry. Are you by any chance an investor in the scheme?

Yes, you can get more work out of your car engine by surrounding it with
Peltiers or other heat engines -- if you drive in the Arctic.

Seriously, if you, a physicist, actually know how to build an engine having no
waste heat, why settle for the chump change of HN publicity? Go for the Nobel
that you deserve.

~~~
hugh3
I think the problem is that you interpreted the headline as meaning it could
convert _all_ waste heat to work. This is, of course, impossible. Converting
_some_ of the waste heat to work is entirely possible.

When there's two possible interpretations of a headline, and one of them is
physically possible and the other one violates the second law of
thermodynamics... it's probably best to assume the former. At least until you
read the article.

