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Flywheels For The Navy
Posted: Thu Feb 05, 2009 8:30 am
by MSimon
Posted: Fri Feb 06, 2009 2:46 pm
by jgarry
Formula One racing is putting a push on for KERS systems. At the moment most of the teams are using battery based systems, but the feeling is that flywheel systems have greater potential, if the bugs can be worked out.
Those guys in the pressure cooker of competition and for the love of their sport are among the great innovators of our time. The investment that folk like Honda have put in to the sport has resulted in great things for their production vehicles. Sadly we here in the US enjoy watching hulking beaters roar around the track, in a most degenerate fashion. Well, at least I do.
Posted: Mon Feb 09, 2009 6:40 pm
by jmc
A flywheel might give a kick to get a high powered fusion reactor starting using a relatively low powered diesel engine.
Posted: Mon Feb 09, 2009 7:23 pm
by David_Jay
On a related topic, the new Ford Class carrier will have an EMALS launch system instead of steam catapults:
http://en.wikipedia.org/wiki/Electromag ... nch_System
Discharge rates of 30+ MJ/sec (100MJ in less than 3 seconds). In VA terms - how about 10,000V@3,000A.
I think that solves the rate issues of mechanical storage to electrical power conversion!
Posted: Tue Feb 10, 2009 1:14 am
by KitemanSA
David_Jay wrote:On a related topic, the new Ford Class carrier will have an EMALS launch system instead of steam catapults:
http://en.wikipedia.org/wiki/Electromag ... nch_System
Discharge rates of 30+ MJ/sec (100MJ in less than 3 seconds). In VA terms - how about 10,000V@3,000A.
I think that solves the rate issues of mechanical storage to electrical power conversion!
Shouldn't we look to much lower voltage and higher amps? If we super-chill the magnet, that is the desire, no?
Oh yeah, and that honker is HUGE!
Posted: Tue Feb 10, 2009 3:12 pm
by David_Jay
My VA illustration was only to translate MJ into something more people can identify with - you could just as well say 1,000,000V@30A or 100V@300,000A
Have you seen a size for a disk alternator? I haven't been able to track down that information.
The size quoted is for the entire catapult, which is obviously big enough to launch an E-3 and more.
Posted: Tue Feb 10, 2009 3:17 pm
by David_Jay
More detail here, but no size for the flywheel, which turns @6000RPM in a vacuum vessel:
http://www.edn.com/contents/images/207108.pdf
Posted: Tue Feb 10, 2009 3:53 pm
by David_Jay
A General Atomics press release in July, 2008 said that the storage subsystem was operational (in Tupelo, MS). They were continuously cycling the system to simulate 250 launches per day.
And the new test facility building is only 5000 sq. ft.
Posted: Tue Feb 10, 2009 6:03 pm
by Aero
The fly wheel stores 100 MJ at 6000 RPM. By making some reasonable assumptions the rotating mass could be estimated. MSimon likes fly wheels, this is a problem for him.
Posted: Tue Feb 10, 2009 7:22 pm
by Aero
For the basic physics of a flywheel, see Flywheel Physics.
Compared with other ways of storing electricity, FES systems have long lifetimes (lasting decades with little or no maintenance[2]; full-cycle lifetimes quoted for flywheels range from in excess of 105, up to 107, cycles of use)[4], high energy densities (~ 130 W·h/kg, or ~ 500 kJ/kg), and large maximum power outputs. The energy efficiency (ratio of energy out per energy in) of flywheels can be as high as 90%. Typical capacities range from 3 kWh to 133 kWh.[2]Rapid charging of a system occurs in less than 15 minutes.[5]
from
http://en.wikipedia.org/wiki/Flywheel_energy_storage
At 500 kJ / kg, I calculate 200 kg, but that seems awfully small.
Posted: Tue Feb 10, 2009 8:10 pm
by KitemanSA
From the second reference in the wiki EMALS article above :
This gives an energy density of 18.1 KJ/KG, excluding the torque frame.
This is SIGNIFICANTLY less than the 500kJ/kg in the "flywheel" article. Oh, and it doesn't include the cooling unit, or the..., or the..., or the...
Posted: Tue Feb 10, 2009 10:42 pm
by MSimon
KitemanSA wrote:
From the second reference in the wiki EMALS article above :
This gives an energy density of 18.1 KJ/KG, excluding the torque frame.
This is SIGNIFICANTLY less than the 500kJ/kg in the "flywheel" article. Oh, and it doesn't include the cooling unit, or the..., or the..., or the...
The lower density may be a function of high pulse power output. i.e. the hardware must be more robust to handle the peak torque. Love to have one of these to kick start the BFG. Crank up your 1 MW DG. Warm it for a few minutes. Start loading the flywheel - 1 minute to load - kick the BFR. Wheeeeee!!!!
Posted: Wed Feb 11, 2009 12:45 am
by KitemanSA
Talk to General Atomics, they may be happy to unload one on you.
On the other hand, Beacon Power is one of several companies that are making much smaller but compoundable flywheel storage units with impressive power outputs for several seconds to minutes.
Posted: Wed Feb 11, 2009 12:51 am
by MSimon
KitemanSA wrote:Talk to General Atomics, they may be happy to unload one on you.
On the other hand, Beacon Power is one of several companies that are making much smaller but compoundable flywheel storage units with impressive power outputs for several seconds to minutes.
If the power delivered can be matched to the voltage and current required this might be a nice cheap way of getting short run controlled power. A HV xfmr and a bunch of diodes. I wonder what a 5 MW for 2 second unit costs?
Posted: Wed Feb 11, 2009 2:06 am
by KitemanSA
MSimon wrote: If the power delivered can be matched to the voltage and current required this might be a nice cheap way of getting short run controlled power. A HV xfmr and a bunch of diodes. I wonder what a 5 MW for 2 second unit costs?
This is the Pentadyne unit. For some reason, the data on the Beacon Power system is being updated without leaving the past data there.
DC input/output voltage --------- Adjustable: 350 to 850* Vdc
Maximum output power --------- 190 kW
Recharging time ----------------- <15 sec. (DC source dependent)
DC ripple ------------------------- <2%
DC output voltage regulation --- ±1% steady state
Standby draw/heat dissipation - 0.3 kW/1,025 BTU/hr
Weight ---------------------------- 1,300 pounds (590 kg)
Dimensions D xW x H ----------- 33x25x71 in (83x63x180 cm)
Operating sound level ----------- 45 dBA@1 meter
Operating temperature range -- -4°F to 122°F (0°C to 50°C)
Cabling access ------------------- Top or side
Service access ------------------- Only front access required
They show 1000kVA for 14 seconds with 5 cabinets. $, they don't say on the web site.