Engine On a Chip May Beat the Battery

Krishna Dagli writes, "MIT researchers are putting a tiny gas-turbine engine inside a silicon chip about the size of a quarter. The resulting device could run 10 times longer than a battery of the same weight, powering laptops, cell phones, radios, and other electronic devices." From the article: "All the parts work. We're now trying to get them all to work on the same day on the same lab bench." The goal is to do that by the end of the year.

Comments

Generator?

[camperdave]

OK, I can picture the gas microturbine, and I can picture how a fuel/combustion energy source can outpower an electochemical energy source. However, do we have the capacity to make a generator that small. After all, we have the rotary power, how do we convert that into electrical energy?

I would be more interested in a bioelectric power source, like electric eel cells fed with sucrose.

Re:p = mv & F =ma

[MustardMan]

the total force cannot exceed the energy output

I think you need to check your units there, boyo.

Re:p = mv & F =ma

[gewalker]

Try 20,000 revs / sec

E = 1/2 mV^2

Mass should be small since mass/volume hase cubing scaling. I expect MIT is not too concerned about it since they did not mention it.

I used to work at Cummins research center -- watch a turbocharger burst test if you get the chance, basically dump in as much fuel/air as it takes to get the flywheel to fly apart. Test is: is the casing is strong enough to contain all the flying pieces.

Scaling down heat engines?

[140Mandak262Jamuna]

When steam engines were invented and developed in England by Newcomen the science of thermodynamics was lagging the technology. The steam engines work obviously but they could not get scaled down versions of the steam engines to work at all in the lab. Mainly because real engines were made with cast iron but the lab models were made with brass and it conducted away the heat away too quickly. At this time a man named James Watt, an instrumentmaker by profession did lots of work on the lab models and made an improved steam engine by mainly making the steam condense outside the cylinder. Also he invented the Watts Governor to regulate the speed of the machine. The moral of the story is that, heat engines dont scale down as easily as electronics.

Fluids in general behave much more differently in microscopic quantities than in large bulk quantities. I expect to be lugging large batteries for some time to come.

Re:Scaling down heat engines?

[giafly]

[Steam engines prove] that heat engines dont scale down as easily as electronics.

Steam engines of the era you're discussing heated water in a big drum, just hot enough so it turned to steam, then cooled it just enough so it condensed back to hot water. Both stages (especially the second) were critically dependent on conduction. The heat engine in the example works by burning a fuel-air mix at the the melting point of steel apparantly, and doesn't bother condensing the result. I think the issues are different.

If there is a moral it's that hybrid cars are f*ing stupid if you can get much better efficiency from a tiny little gas engine than from a battery.

Re:I wonder how safe they will be?

[cosmicj]

yeah, what happends when the ballbearings wear out??

Re:p = mv & F =ma

[gewalker]

Hate to reply to myself as a general rule, but I thought a little searching would pay off.

Here is a movie from Rolls Royce, not exactly the same, but it's nice.

Re:I wonder how safe they will be?

[AncientPC]

How is this any different from spinning platters in hdds?