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Heat Engines Shrunk By Seven Orders of Magnitude
KentuckyFC writes "The vast majority of motors that power our planes, trains, and automobiles are heat engines. They rely on the rapid expansion of gas as it heats up to generate movement. But attempts to shrink them by any significant amount have mostly ended in failure. Today, the smallest heat engines have a volume of some 10^7 cubic micrometers. Now group of Dutch engineers has built a heat engine that is seven orders of magnitude smaller than this. The engine consists of a piezoelectric bar that expands and contracts in the normal piezoelectric way. However it also heats up and cools at the same time causing a thermal expansion and contraction, which lags the piezoelectric displacement. By carefully choosing the frequency of the driving AC current, the Dutch team found a resonant effect in which the thermal expansion and contraction amplifies the mechanical motion, making it a true heat engine. Operating the thermodynamic cycle in reverse turns the device into a heat pump or refrigerator. The total volume of the device is just 0.5 cubic micrometres."
You know how big a millimeter is, right? A micrometer is one thousandth the length of a millimeter.
A cubic micrometer is the volume occupied by a cube one micrometer on each side.
10^7 cubic micrometers would fill a cube about one-fifth of a millimeter on a side. Smaller than a pinhead.
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
It is so small that it produces a very minimal amount of horsepower, which is not useful for any actual way.
Unless of course you have several billion of them on a gram sized object. If you can't see the value in jet powered ants you should turn in your nerd card.
Seven puppies were harmed during the making of this post.
Assuming we had micro engines, we can take full advantege of many things that are better smaller than bigger.
For example, a small device that turns heat into power could power an IMPLANTABLE MEDICAL DEVICE using the bodies own heating/cooling systems? No more changing the battery for the pacemaker every
Then there are small flying devices. I am sure the military would love a flying camera the size of a real fly that uses the solar heat of the sun to power it.
Then there are phones and musical devices. Want one that uses half of its' own waste heat to recharge itself, perhaps doubling battery life?
excitingthingstodo.blogspot.com
Somehow "heat engine" directly translates into "internal combustion engine" for me.
That's too bad, I hope this article will be enough to let you correct your thought
why emphasize that it is a heat engine?
Because they figure it's mostly usefull as a heat pump, not as a mechanical actuator.
You can't take the sky from me...
And I despair of the lack of English education, specifically reading comprehension.
This isn't internal combustion, which is what your argument is based on. It uses the fact that solids expand and contract when heated and cooled, including some piezo materials.
Please read the summary *again*.
The range of topics covered here is very wide and I don't know abc of several things discussed here. Does that make me stupid and pathetic?
The key point is that you recognize that you don't know everything about the topic at hand. The post that sunking2 was responding to was essentially a spew of vitriol against the researchers, claiming that it's impossible to make such a small engine with any sort of efficiency, and that they're stupid and ignorant for even trying. According to that post's replies, the writer is completely wrong and doesn't know some basic facts about the subject they're yelling about.
So, no, you're not at all stupid and pathetic for not knowing everything about everything, and I'm in the same boat with you (I've learned a fair amount from this story's discussion), but neither of us is telling everyone (including the Dutch engineers in question) that they're stupid and don't know what they're talking about.