Re: flywheel home energy storage [non vacuum]

Constructing a windmill is not very hard[1] The big problem with wind

> energy is the number of batteries. The wind doesn't blow all of the > time after all. > > I find the following example[2]: > > "A 1 foot diameter flywheel, one foot in length, weighing 23 pounds > spinning at 100,000 rpm will store 3 kWh of energy. However at this > rotational speed the surface speed at the rim of the flywheel will be > 3570 mph." > > This is the typical description one finds. The speed is very > unrealistic but the weight seems to be an even stranger figure. In > stead of using only 10 kg we can quite easily use 1000 kg or 5000. > Weight doesn't seem to be a problem of resources. To give the number a > crude swing 3570 / 500 = 7.14 mph This doesn't seem to be a lot. > > A vacuum isn't really necessary, we pay for the losses in wind after > all. When we move the mass to the rim of the wheel it seems possible > to float such flywheel in a ditch in the back yard. > > Storing 1 kWh using batteries costs between 250-500 $ > > Batteries have very limited life span and it's hard to step down the > charging voltage. It seems far easier to use a motor to dump the wind > into a rotating mass. The flywheel could be huge but digging a hole in > the ground doesn't cost much space at all. > > A 10 ton block could be "disappeared" into the ground quite easily. > The energy density of flywheels can be 2 times as high as that of high > tech batteries.[3] When we loose some of that edge though cheap > engineering it would still equate to 20 tons worth of battery packs. > Keep in mind, a big propeller is also relatively cheap.[1] > > I'm trying to get an idea how fast such flywheel would run down. A > smooth surface spinning in water. What kind of drag does that produce? > I think it could take a lot of days for it to run down. > > a note: > Applied physics would look good on your resume, there could be some > serious money in this if you want to help. I'm a honest guy :-) The > world needs saving, going off-grid is just to expensive. The debunkers > pretend return on investment is poor but they seem all to happy to > ignore the dwindling currency and the sky rocketing energy prices. > Compare the mortgage rates with 30 years ago. The demand for batteries > isn't going to come down either, this will most likely will drive up > the prices before production can match it. The green bottle neck is > the energy storage technology. Generating power isn't much of an > issue. Storage is just way to expensive, unreliable and hard to mass > produce. > > [1] -
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[2] -
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[3] -
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>a video >
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>___________________ >
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> > > >> Constructing a windmill is not very hard[1] The big problem with wind > >> energy is the number of batteries. The wind doesn't blow all of the > >> time after all. > > >> I find the following example[2]: > > >> "A 1 foot diameter flywheel, one foot in length, weighing 23 pounds > >> spinning at 100,000 rpm will store 3 kWh of energy. However at this > >> rotational speed the surface speed at the rim of the flywheel will be > >> 3570 mph." > > For a circular cylinder of mass M and radius r, the moment of inertia > about the cylindrical axis is given by > > I = (1/2)*M*r^2 > > So for your cylinder of 23 pounds mass and diameter of one foot (radius > a half foot) you get: > > I = 0.121 kg*m^2 > > or, if you insist upon non-metric units, > > I = 2.875 lb*ft^2 > > The rotational energy stored in a body rotating at w radians per > second and with moment of inertia I is: > > E = (1/2)*I*w^2 > > Now, 100,000 rpm is w = 1.047 x 10^4 Hz, yielding for the energy: > > E = 1.845 kWh > > That's half of Gaby's claim. He's got the rim speed right though. >

I got the numbers from the referenced website.

> >> This is the typical description one finds. The speed is very > >> unrealistic but the weight seems to be an even stranger figure. In > >> stead of using only 10 kg we can quite easily use 1000 kg or 5000. > >> Weight doesn't seem to be a problem of resources. To give the number a > >> crude swing 3570 / 500 = 7.14 mph This doesn't seem to be a lot. > > Easily? Bearing wear and frictional losses will become significant as > the mass increases. The obvious alternative is to increase the moment > of inertia by increasing the radius while holding to a manageable mass. >

The story goes something like this Greg,

First people work really hard for nothing, Then people work really hard for barely enough, Then people work hard and have enough to stay alive, Then people work normally and have a little bit of luxury, Then people barely work at all and have more than they need, Then people loose themselves in trivial activity while thinking they deserve much luxury.

After that the whole system collapses,

Without suffering people don't have sufficient motivation to act rationally.

You see this in small business, small towns, big towns, big businesses, countries, multinationals and you also see this globally.

All people working in finance, services, marketing, police or tax office are not producing anything we can eat.

They are 100% convinced they deserve everything they have but it has no context with peoples real needs.

In the west we need energy solutions. There is no "maybe" in this, people pay enormous amounts of labor for something that should technically be free.

We don't have the technology to create a flat rate system because it has been shelved away by the petroleum sector, the automakers and mostly the military. Free energy is very dangerous on the battle field. I have investigated all kinds of energy sources, the only bottle neck is peoples believe systems. There are lots of classified solutions but we cant use those because it is not for us to decide.

The earliest flywheels however are as old as grinding flour.

I'm not telling you you cant amuse yourself with the subject. Quite the contrary, it should be big fun to search and find solutions for the obvious problems we have on this planet.

The idea merely compares expensive batteries with inexpensive flywheels.

The idea was for the flyweel to float and for the electric motor to be directly connected to a windmill.

A domestic windmill tends to be to small to power an entire house but if we forget about the luxury and look at the worse case scenario it becomes obvious that a little bit of power is quite a lot more than nothing at all.

The absolute minimum would be to have a bit of light in the house. This would only require a few 3 Watt supper LED's

1 kwh would be enough to power such led for 333 hours. This can be generated with a very small propeller and it doesn't require a lot of batteries.

But one good battery may already cost 400 euro.

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But we want more don't you agree? You can already see the 3 watt example does not earn back it's own value before breaking down. But quite surprisingly the engineers and marketeers don't show much understanding of economic effects. Regardless of what the goal of a planning is one is to assume worse case scenarios. The petroleum and coal situation is not exactly stable or even reliable. To calculate the reliability of a wind power system one can not assume purchasing power is a fixed value. It is amateurish to calculate ROI over 30 year.

30 years ago I could buy a house here for 10 000 Euro. This same house costs 600 000 Euro today. This was without an economic collapse or a giant disaster. It is not a leap of imagination to assume a wind powered system will be 60 times as expensive 30 years from now. If the west keeps up it's trivial activities the economy is absolutely going to crash. The 1000 Euro wind installation you can buy today can quite easily ramp up to cost 100 000 Euro. It can happen in a few years, months or even days.

So where I say "Easily" I'm referring to an easy way out of the scheme of global death. I don't feel like following this agenda blindly. I'm not suggesting people should make bio fuel at home, alcohol, or gas from their poop. That is labor intensive and hard to learn.

A 5 ton flywheel is easy to make but that doesn't mean it is a suitable solution. I'm trying to figure out what a viable size could be.

For reference, grid tied inverters start at about 1200 euro.

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Those require a minimum input current and they are also restricted by a maximum. This same problem presents it self choosing a generator, wiring, batteries and chargers.

A flywheel is perfectly fit for load balancing. It behaves very forgivingly. Small propellers don't produce a lot of power, add some inverters and batteries and quite a lot of it will be lost.

There are surges of high voltage available, but for a few hours per week it's not worth over engineering. It may have to be shut down entirely.

The ideal setup would be to fit the flyweel onto the roof but that would require designated construction from the ground up.

A chain, belt or flexible axle could be used to transfer the motion to said underground mechanical storage. But I think delivering the energy electrically could be a viable solution. The flywheel is going to have losses anyway.

The basic idea is to generate and store a bit more than it looses over time. But it may also provide mechanical energy. I'm wondering how much power the drag will really consume. If it's really bad, the floating flywheel may provide hot water.

Look at it as-if an adventure, there are lots of tricks worth taking a look at and giving them some thoughts. :-)

I do respect how spoiled we are but dashing all the solutions off the list doesn't leave us with a viable solution. We need to expand the list and make the good stuff float to the top.

It's fun, the goal isn't something trivial.

I know the global games going on, the next world war is scheduled, Barbie and Kent will either have to row or drown. We can "do or die?" What other options do you see?

It are the small things make all the difference.

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"The new generator runs efficiently over a wider range of conditions than conventional generators do. When the shaft running through an ordinary generator is turning at the optimal rate, more than 90 percent of its energy can be converted into electricity. But if it speeds up or slows down, the generator's efficiency drops dramatically. This isn't a problem in conventional power plants, where the turbines turn at a steady rate, fed by a constant supply of energy from coal or some other fuel. But wind speed can vary wildly. Turbine blades that change pitch to catch more or less wind can help, as can transmissions that mediate between the spinning blades and the generator shaft. But transmissions add both manufacturing and maintenance costs, and there's a limit to how much changing the blade angle can compensate for changing winds.

ExRo's new design replaces a mechanical transmission with what amounts to an electronic one. That increases the range of wind speeds at which it can operate efficiently and makes it more responsive to sudden gusts and lulls. While at the highest wind speeds the blades will still need to be pitched to shed wind, the generator will allow the turbine to capture more of the energy in high-speed winds and gusts. As a result, the turbine could produce 50 percent more power on average over the course of a year, says Jonathan Ritchey, ExRo's chief technology officer. Indeed, in some locations, the power output could double, says Ed Nowicki, a professor of electrical engineering at the University of Calgary, who has consulted to ExRo.""

>> A vacuum isn't really necessary, we pay for the losses in wind after > >> all. When we move the mass to the rim of the wheel it seems possible > >> to float such flywheel in a ditch in the back yard. > > >> Storing 1 kWh using batteries costs between 250-500 $ > > >> Batteries have very limited life span and it's hard to step down the > >> charging voltage. It seems far easier to use a motor to dump the wind > >> into a rotating mass. The flywheel could be huge but digging a hole in > >> the ground doesn't cost much space at all. > > >> A 10 ton block could be "disappeared" into the ground quite easily. > >> The energy density of flywheels can be 2 times as high as that of high > >> tech batteries.[3] When we loose some of that edge though cheap > >> engineering it would still equate to 20 tons worth of battery packs. > >> Keep in mind, a big propeller is also relatively cheap.[1] > > >> I'm trying to get an idea how fast such flywheel would run down. A > >> smooth surface spinning in water. What kind of drag does that produce? > >> I think it could take a lot of days for it to run down. > > On Fri, 19 Dec 2008 02:16:06 -0800 (PST), gabydewilde > > wrote: > >Constructing a windmill is not very hard[1] The big problem with wind > >energy is the number of batteries. The wind doesn't blow all of the > >time after all. > >Batteries have very limited life span and it's hard to step down the > >charging voltage. It seems far easier to use a motor to dump the wind > >into a rotating mass. The flywheel could be huge but digging a hole in > >the ground doesn't cost much space at all. > > Good thinking! Several loose ends but fundamentally an intriguing > direction. > > Note that Formula One racing was encouraging the use of regenerative > braking for their race cars. In the scramble, flywheel storage was > at least holding its own versus generator battery (or > ultra-capacitor) combinations. > > Note also that the Formula One flywheel technology uses a variable > ratio transmission to transfer power to and from the flywheel. That > may be an essential ingredient for windmill storage. > > Its easily shown that simple frictional linkage into/out-of the > flywheel will consume one half of the energy that eventually is stored > or released. Continuing the analogy to capacitive electrical storage, > are there ways to use elastomeric linkages in combination with the > flywheel to absorb bursts of energy efficiently--inductors combined > with capacitors do this for electrical storage--eg electronic flash > units? > > Consider that possibly the best system never converts its energy to > electricity--mechanical motion from the windmill can be converted to > inertial energy turning the flywheel which warms the water due to > viscous drag and turbulence. The inertial momentum is then tapped to > drive a heat pump which draws heat from the warm water to warm the > house. > > >A 10 ton block could be "disappeared" into the ground quite easily. > >The energy density of flywheels can be 2 times as high as that of high > >tech batteries.[3] When we loose some of that edge though cheap > >engineering it would still equate to 20 tons worth of battery packs. > >Keep in mind, a big propeller is also relatively cheap.[1] > > >I'm trying to get an idea how fast such flywheel would run down. A > >smooth surface spinning in water. What kind of drag does that produce? > >I think it could take a lot of days for it to run down. > > The whole concept demands a large amount of engineering calculations. > Good luck! > > > On Fri, 19 Dec 2008 02:16:06 -0800 (PST), gabydewilde > > > wrote: > > >Constructing a windmill is not very hard[1] The big problem with wind > > >energy is the number of batteries. The wind doesn't blow all of the > > >time after all. > > >Batteries have very limited life span and it's hard to step down the > > >charging voltage. It seems far easier to use a motor to dump the wind > > >into a rotating mass. The flywheel could be huge but digging a hole in > > >the ground doesn't cost much space at all. > > > Good thinking! Several loose ends but fundamentally an intriguing > > direction. > > Well thank you. :-) > > Here is the video. > >
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> > Note that Formula One racing was encouraging the use of regenerative > > braking for their race cars. In the scramble, flywheel storage was > > at least holding its own versus generator battery (or > > ultra-capacitor) combinations. > > > Note also that the Formula One flywheel technology uses a variable > > ratio transmission to transfer power to and from the flywheel. That > > may be an essential ingredient for windmill storage. > > > Its easily shown that simple frictional linkage into/out-of the > > flywheel will consume one half of the energy that eventually is stored > > or released. > > I'm not sure if you can say "half" like that. If it's not being used > the system will have 100% losses. If you draw a huge load the flywheel > will supply what you need far beyond that what a battery can give you. > > Building a big windmill doesn't cost much, specially if it can be > fitted on the roof of a house. > > But the erratic wandering current coming out of it is not very > practical. In most cases it is to expensive to buy such batteries, > buying to much of them for occasional supper wind is also wasteful. > Any economically feasible number of battery packs cant absorb the peak > current. > > > Continuing the analogy to capacitive electrical storage, > > are there ways to use elastomeric linkages in combination with the > > flywheel to absorb bursts of energy efficiently--inductors combined > > with capacitors do this for electrical storage--eg electronic flash > > units? > > Oh, I think there are but a strong electric motor with good randament > is not expensive. > > > Consider that possibly the best system never converts its energy to > > electricity--mechanical motion from the windmill can be converted to > > inertial energy turning the flywheel which warms the water due to > > viscous drag and turbulence. The inertial momentum is then tapped to > > drive a heat pump which draws heat from the warm water to warm the > > house. > > Excellent thinking. Heating up the flywheel and the watter will store > a lot of heat. It may even reduce friction. From what I tested thus > far I expect friction to be rather "disappointing". Making it bigger, > heavier and increasing the radius seems to decrease the drag faster > than it goes up. The flotation will also have to be balanced against > the price of bearings. Creating a vacuum seems expensive but it might > be cheaper than we think. > > > >A 10 ton block could be "disappeared" into the ground quite easily. > > >The energy density of flywheels can be 2 times as high as that of high > > >tech batteries.[3] When we loose some of that edge though cheap > > >engineering it would still equate to 20 tons worth of battery packs. > > >Keep in mind, a big propeller is also relatively cheap.[1] > > > >I'm trying to get an idea how fast such flywheel would run down. A > > >smooth surface spinning in water. What kind of drag does that produce? > > >I think it could take a lot of days for it to run down. > > > The whole concept demands a large amount of engineering calculations. > > Good luck! > > I think just building it would be an easy way out. > > Bit of cement? How expensive can it be? > > ________ >
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Reply to
gabydewilde
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anything at all is good for a back-up, for the essentials.

you don't want that on your roof, because of the Coriolis effect during an earthquake; you may not feel a MM2 quake, but youur wheel will.

Reply to
spudnik

Hmmmm...this looks like a sci.physics post? Kinetic energy goes as speed squared. Dividing the speed by 500 divides the kinetic energy by 250,000. Multiplying the mass by 500 increases the energy store by 500. Then you would have 3000 watt hours X 500 / 250000 = 6 watt.hours or

21.6kJ if the original numbers were representative.

BrianW

Reply to
Brian Whatcott

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