This week's Proceedings of the (US) National Academy of Sciences reports a new high temperature super-conductor, with a critical temperature up at 73K (which is still well below room temperature but above the 66K which was the previous peak).
I can get access to the full paper if anybody is interested.
Nobody is talking about making cables out of the stuff yet, or even speculating if it could be made into a conducting lead.
-- Bill Sloman, Sydney
Not very interesting, since it is still below 77 K, the boiling point of liquid nitrogen.
In addition to the temperature, the other critical parameter is the maximum current densities supported by any exotic HTS. They tend to loose superconductivity if too high current densities are used, so wide sheets of metal is needed to carry a decent current. AC is out of the question for such cables and even bringing up a DC current can take a long time.
Yeah I don't get the numbers. YBaCuO's are ~90 K. (an other higher ones... no idea about the critical currents/ B-fields.)
George H.
I thought there were super-conductors that operate at much higher temperatures than that, what's the catch?
--
Thanks,
- Win
I don't accept the hype about using superconductors for power transmission anyway. It's not as if the existing transmission infrastructure wastes that much, and the infrastructure required to keep cables cool would be hugely expensive.
Seems to be a solution looking for a problem and one that would be killed by economics.
Sylvia.
It's easy to tell this is an engineering group. When research is announced it is immediately criticized if it isn't ready for commercialization. In this case no one is talking about this being an immediately useful substanc e. Rather they say, "with two unique features: an exceptionally compresse d local octahedron and heavily overdoped hole carriers. These two features are in sharp contrast to the favorable criteria for all previously known cu prate superconductors. Thus, the discovery of high-Tc superconductivity in Ba2CuO4-y calls into question the widely accepted scenario of superconducti vity in the cuprates. This discovery provides a direction to search for add itional high-Tc superconductors."
In other words, "Hmmm... isn't this curious? Let's take a better look."
Superconductivity is still a new field with lots of corners to look around. Much of the research is still a matter of searching a rather large tree.
-- Rick C. - Get 1,000 miles of free Supercharging - Tesla referral code - https://ts.la/richard11209
A superconducting cable has a constant dissipation due to the cooling. With sufficient power, the cooling losses are smaller than the copper losses in ordinary HV lines. Unfortunately, the breaking point is about 10 GW for a few thousand kilometer links. Such power levels require a few nuclear reactors or something like full scale DESERTEC solar power system (politically too risky after the Arab spring).
The refrigeration costs are pretty small actually. The Ampacity project is running a 1 km, 10 kV, 4 kA cable with good results. The power used to keep the cable cold appears to only be 43 kW or about 0.1%. The actual cooling used is only about 1.8 kW.
The power industry is not stupid. They can figure out what will work and what won't. If there was no need, no one would be looking at it.
-- Rick C. + Get 1,000 miles of free Supercharging + Tesla referral code - https://ts.la/richard11209
Failures would be spectacular and slow to repair.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
So, just like bridges, oil pipelines, and aircraft softwares. Sounds good, let's do it!
The experience is with liquid helium technoology (too expensive). A grid-scale application of superconducting links can be economic as materials and technologies evolve.
Superconducting inductor as bulk energy storage, pump energy in and the current goes round and round and round. Failure would also be spectacular but most high density energy storage failures usually are
One idea was a miles-in-diameter superconducting coil to store energy.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
One of those megaprojects where I would say the chances between it and a transatlantic maglev train from New York to London via Greenland, which will come first, about 50/50. I'm hoping for the train
It wasn't too long ago Larkin was singing his praises of brainstorming and how valuable the people who will propose extreme ideas were. When he hears about someone else running a new idea up a flagpole to see who salutes he has to ridicule it.
Will the maglev train be in a tunnel? Hopefully it will be more comfortable than a plane.
-- Rick C. -- Get 1,000 miles of free Supercharging -- Tesla referral code - https://ts.la/richard11209
It didn't sound like ridicule, exactly. It's a pretty old idea I think. Only really feasible with "room temperature" superconductors given the size the thing would have to be to store appreciable energy to make it worth the time, but all sorts of wild stuff would be possible with a ductile, machinable room-temperature superconducting material it'd be one of the greatest discoveries in engineering/materials science history, surely.
I would expect, even the parts on land would be in a vacuum tunnel of some kind. To be competitive with air travel times.
The economic advantage would be the enormous number of people a single train could haul, four trains or so each way per day hauling several thousand people each would cover pretty much the entire current transatlantic NYC - London air travel demand
There was a plan to put it in a submerged but near the surface tunnel across the atlantic and pump the atmosphere out. Expected speed was
18,000 miles per hour but it would take the whole of the planets production of steel for a year to accomplish. This was well before Musks hyperloop idea.-- Regards - Rodney Pont The from address exists but is mostly dumped, please send any emails to the address below e-mail rpont (at) gmail (dot) com
I wonder how you would keep it from floating?
-- Rick C. -+ Get 1,000 miles of free Supercharging -+ Tesla referral code - https://ts.la/richard11209
If you're going to go that fast might as well go Labrador -> Greenland
-> Iceland -> UK you "only" have to cross like 700 miles of open water that way.
18,000 mph is an impossible speed there's not enough distance to accelerate and slow down gently enough, making your passengers pull 5 Gs like an astronaut on launch is bad for ticket sales! 1000 - 2000 mph is fine
at the top end of that range, even, acceleration and deceleration would have to be carefully managed with tilting seats or something to keep your passengers from puking
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