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."

Comments

Re:Usefulness?

[gurps_npc]

No. You have made a critical error in thinking. You need to think relativity wise. Scale changes how much power we need. As of yet we don't have many small things that need small amounts of power because we have NOT had the engine. Now that we have the small heat engine, it will allow us to develop small devices that use it.

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?