Kick starters and flywheel technology

[DanKegel]

the velkess flywheel is a lot less technically challenging to produce than a personal supersonic jet.

According to http://www.scientificamerican.com/ar...ywheel-design/ it has a diameter of 66cm and spins at 9000 when "discharged"
The linear speed at the edge is pi * 66 cm * 9000 rpm / 60 min/sec = 310 meters/sec
Presumably it spints at least twice that fast when charged.
The speed of sound is about 340 meters/sec.

So it has something in common with the jet: both are supersonic

[Sunking]

So it has something in common with the jet: both are supersonic

Dan you really do not get it do you? A battery has a power efficiency of roughly 80%. When fully charged it requires almost no power to stay charged up. Flywheel efficiency is single digits. At very best is if you spool up a Flywheel, and then immediately dump the energy efficiency is roughly 50 to 60% due to 3 energy conversions . Want to use that energy a few hours later and efficiency is single digits.

Flywheels can be used in certain applications where you need a huge amount of power in a very short period of time. I have installed a few in data centers back in the late 90's and up to 2003. They all have been replaced with conventional UPS systems. All of them failed in a few short years and one exploded when then flywheel failed and flew apart. Bu there is the catch in mission critical systems like communications and data centers power and efficiency is of no concern. Does not matter if the storage system is 5% efficient or 80% efficient. In a RE application efficiency is everything, and that seems to completely escape you and others like Ian.

Which is better for the environment?

Two train loads of nasty coal is delivered. Panels are made from one train load of coal and in 25 years you get 4 to 6 units of energy out of it. The other train load is used to build power plant burning coal and delivers 40 to 60 units of energy. Which do you choose?

Same analogy can be used with cash investment. You have two investment plans. Plan 1 is you give me $1 today, and 25 years from now I give you $6. Plan 2 is you give me $1 and 25 years later I give $40 to $60.

You chose plan 1.

[DanKegel]

Dan you really do not get it do you?

Was my last post inaccurate?

[russ]

Your last post and all posts on the flywheel are like a teenager it seems.

The only two things that count wit a flywheel are rpm and weight.

[inetdog]

Your last post and all posts on the flywheel are like a teenager it seems.

The only two things that count wit a flywheel are rpm and weight.

No!
Diameter counts too (actually the details of weight distribution from axle to circumference.)

[russ]

No!
Diameter counts too (actually the details of weight distribution from axle to circumference.)

amount of rotating mass - or weight in simple terms

[inetdog]

amount of rotating mass - or weight in simple terms

No. That is the difference between linear and angular momentum and the corresponding kinetic energy for translational and rotational motion.

Double the mass in either and you double the energy.
Double the speed (linear or angular) in either of them and you quadruple the energy.
But double the radius of the flywheel, keeping the total mass the same and you also quadruple the energy for the same angular velocity (i.e. RPM).
An efficient flywheel design with a limited size concentrates the mass at the rim to the extent that it can be done without compromising structural integrity.

[Mike90250]

Was my last post inaccurate?

"So it has something in common with the jet: both are supersonic"

uh, what is the speed of sound in a vacuum ?

[russ]

No. That is the difference between linear and angular momentum and the corresponding kinetic energy for translational and rotational motion.

Double the mass in either and you double the energy.
Double the speed (linear or angular) in either of them and you quadruple the energy.
But double the radius of the flywheel, keeping the total mass the same and you also quadruple the energy for the same angular velocity (i.e. RPM).
An efficient flywheel design with a limited size concentrates the mass at the rim to the extent that it can be done without compromising structural integrity.

Oh gee!

[kwilcox]

...An efficient flywheel design with a limited size concentrates the mass at the rim to the extent that it can be done without compromising structural integrity.

That's how mass is distributed in the velkess flywheel design too. Kevlar rope forms a flexible spinning loop which is where most of the 40" cube's 750 lb weight lies.

[kwilcox]

...A battery has a power efficiency of roughly 80%. When fully charged it requires almost no power to stay charged up. Flywheel efficiency is single digits. At very best is if you spool up a Flywheel, and then immediately dump the energy efficiency is roughly 50 to 60% due to 3 energy conversions . Want to use that energy a few hours later and efficiency is single digits.

The Velkess prototype demonstrated an efficiency that was a little greater than 80%. I said "demonstrated" Russ. The design is proven and pre-production units have been built. The only thing that remains is whether these devices can be profitably mass produced at the given price point.

[SunEagle]

"So it has something in common with the jet: both are supersonic"

uh, what is the speed of sound in a vacuum ?

If a tree falls in the woods and .... never mind.

[SunEagle]

The Velkess prototype demonstrated an efficiency that was a little greater than 80%. I said "demonstrated" Russ. The design is proven and pre-production units have been built. The only thing that remains is whether these devices can be profitably mass produced at the given price point.

I agree that the Velkess flywheel technology is a cut above some of the older types and may actually find a place (at a cost) to be an effective energy storage unit.

I still don't like the idea of asking for funds through "kick start" which IMO is for people trying to build something that has limited market share.

If Velkess has found the holy grail of energy storage you would have very big investors running for the chance to be part of a revolutionary technology. Even someone like Bill Gates who has invested in a number of RE technology system hasn't given 1 penny to Velkess.

[russ]

So buy them - they are constantly looking for suckers that believe the BS line they are spreading.

[Alisobob]

The speed of sound is about 340 meters/sec.

So it has something in common with the jet: both are supersonic

The speed of sound in a vacuum , where this thing is supposed to operate.... is... zero.

Again, more cliche's , no facts.