Discussion in 'Architecture & Engineering' started by vslayer, Apr 23, 2008.
Didn't Noddy have a windup car?
Log in or Sign up to hide all adverts.
No, not so. - You must have misunderstood my POV. Certainly one can gimbal a stationary flywheel storage system to accommodate a few hours of Earth's rotations, and they will be used, instead of peaking gas turbines in the not too distant future to "shave peaks" - this is a natural development very compatible with nuclear power as those capital-intensive fuel-cheap units need to be "base loaded" 100% of the time if possible.
What I said was that storing in buried backyard flywheel over night energy from your homes solar panels is not attractive because that would require 180 degree gimbals for the first Earth's12 hour of Earth rotation and it gets worse as time passes. I.e. The gimbals must rotate 270 degrees for 18 hours, 360 degrees for a night followed by cloudy day, etc. Pretty soon the wires from the generator are wrapped up tight and at best break, but may short out and destructively dump energy. Now one can use part of the stored energy to torque the angular momentum constantly so that it remains with the local vertical, but that too gets complex and adds expense and some constant energy drain.
I my years ago post recommending the flywheel bus, I did note that there would be some hills too steep for the bus, even if the electric motors, which would be DC for the low speed or stalled bus's torque requirements, could generate the necessary torque. As I recall, I thought the gimbals should allow at least 30 degrees up and down for the bus on hills. The fact that the energy storage is nearly exhausted at least once per hour (Use only few Power Poles along the route, which is fixed and scheduled to assure this. Then little energy or capital is wasted in the low capacity "torque vertical" alignment system.* - Obviously the "power poles" are not on the hillsides, but where it is level.)
On first thought, I do not think it is an attractive idea, but probably it is possible to have two counter rotating flywheels in the same gimbals system - no net angular momentum. Perhaps one should think a little more about this, as there is some redundancy and less energy to dissipate safely in case of failure also.
I do admit that the bus dropping wheel into a pot hole etc is an extra concern for the magnetic bearing designers that is not present in the backyard buried unit. (Unless there is a minor earthquake - then the massive bus on its regular springs has the advantage.)
I disagree. It is the total accumulation of rotation during the storage period, not the rate of rotation (with in the gimbals limits) that is important. As bus goes up and then down a 25 degree hill, there is no problem even if it has 60 miles per hour speed. (With 30 degree gimbals.) In contrast, even if the day were 30 hours long for slower rotation, the wires still will wrap up and break in the same number of days. - of course you can take the power out thru slip rings - I am just trying to drive home the point that the Earth's rotation ACCUMULATES and the backyard units gimbals must be able to turn fully around more than 1000 times in three years. The bus unit gimbals never accumulate 30 degrees of rotation in the 10 year life of the bus. BTW, the flywheel storage system may need the electric motors periodically repaired, but the basic storage system is so "wear free" that it should be transferred thru about a half dozen busses in turn as they wear out. Contrast that with the electric battery bus: It will need a half dozen sets of batteries before the bus wears out.
* Because there is so little loss with power transfer and power can be quickly transfered (60 times faster than battery so what battery needs an hour for, flywheel can do in a minute) it is not unreaonable to fully drain the remaining stored energy from the flywheel into the power pole. Then let the weight of th non spining flywheel make it vertical and re charge. - No expense for vertical torquing system etc. The backyard storage flywheel could do somewhat the same thing with the power grid, but the electic company would not like that as on sunny afternoon all would want to do so and recharge later from the power line as nite comes. - I.e. make their load less diversified and exagerate the peaks etc. - They will not let the capital cost of the accumulating Earth's rotation be transfer back to them in form of more peaking units required. etc. Power companies do not like to talk about it as it sounds "anti-green" but they already see the problem with simple solar cells that "run the meter backwards." Every home in the sun at same time with no lights on wants the power company to pay for the energy storage system. Eat the cost of a worse peaking system, but it not serious yet as so few meters do "run backwards" on sunny days.
Or rotary transformers, which don't wear down with friction, and can handle higher rotating speeds.
BillyT- There's no need to gimbal stationary flywheel batteries. If you take a closer look at the ones in development, or even at the growing number of them entering service today, you'll discover that a fixed vertical axis is commonplace. The force of precession being diverted 90 degrees in the direction of rotation is not rotational velocity of the flywheel- it's the prodigious rotational inertia of our planet. There's negligible kinetic storage loss due to precession, because these tall cylindrical flywheels use tidal force to counter precession. Additionally, magnetic bearings are very efficient at handling large forces with minimal friction from one (upper) end.
The RPM website explains inherent verticality, achieved by exploiting gravity and magnetic bearings thusly:
Back to large mobile kinetic batteries, tall cantilevered spindles are not so practical for crash-safety reasons. But in the stationary application, the potential for superior economics and reliability (compared to chemical batteries) is very exciting.
Power and Telephone companies are now purchasing flywheel battery banks for smoothing out their grid service. Kinetic batteries may be simpler to implement than you first thought. Rejoice! Invest!
Next year, Formula One cars will finally be allowed to use regenerative braking, specifically using a flywheel.
Thanks. I did not investigate much yet, but understand now that the spinning flywheel does not need any constructed troquing device if "hung from the top" as then small tilt will allow gravity to apply the torque needed to keep the spin axis nearly aligned with the local vertical.
I was of course well aware the there is no energy required, in principle to change the orientation of the spin axis. (The torque force is orthogonal to the (angular) motion it produces so no work is done.) This is well illustrated in a low friction gyroscope sitting on a table and precessing with essentially no lowering (none if there were no friction losses) of its center of mass. Any energy loss that I spoke of was, like the extra cost, associated with the losses in the torquing mechanism itself, which I falsely assumed would be required, but now I see that clever design can eliminate the need for any such mechanism.
My initial thought about this problem were more along the lines of making the total angular momentum zero by having two co-axial counter-rotating spinning masses. I am glad to learn there is a simpler solution.
Thus I now agree that even over night storage is feasible, but it is interesting that the power companies are also thinking of shorter term load leveling or smoothing applications first. This is no doubt due to the not well appreciated fact that most (typically 80% or more) of your electric bill is not the fuel cost, but mainly the capital cost. Thus, reducing the peak demand (by returning to the grid some stored energy) is very cost effective compared to building larger generation capacity that can handle the peak load.
Many, probably most, power companies that have access to natural gas use gas turbines to service the peaks, even though they are not as efficient, because they are low capital cost per KW of generation capacity. They only run a few hours on a few days each month, so fuel efficiency is not so important.
All of this does not dampen my enthusiasm for the flywheel bus - it increases it as now there will the stationary market for longer term storage in super flywheel to support their production in larger quantities. Thanks again. As they say: "A little knowledge is a dangerous thing" - I am better informed now. Thanks again - it is even better to learn than to teach. When I have time I will investigate this more.
PS Sorry this was double posted over night – I did not know it got posted at all – computer had some loop so bad even Control-Alt- Delete was ignored and only removing power turned it off. I thought post was lost. There was no virus, unless it removed itself.
What we need is a plug-in hybrid that has a 60 to 100 mile range. Then perhaps we could use a solar panel to charge it if the Utility raises price too high....
Assuming 60 mile range and a midsize car that uses 300 WH/mile, we need 18 KWH of energy to refill. We can use a 3000 Watt solar panel. Then your carbon foot print would be zero.....
To be simple and reasonable, let’s run car at a mile/minute. (60mph & one hour of driving each day to go your assumed range.) Then that midsize car is using 300WH/minute or 300x60Wminutes /minute or 18,000W or 24.14 horse power, since 745.7 watts is one horse power. That seems a little low to me, especially if the air conditioning on, but is reasonable.
I am more concerned with getting 18KWH from only a 3000W panel.
There is the “size problem.” - It is hard to get 0.1KW of electric power per square meter of panel even from noonday sun in most of US. That alone requires about 30 square meters of Panel. You certainly need more than 30 square meters of panels as charge and discharge cycle of battery is about 50% efficient. The Panels will at least cover the entire “sun side” of the roof of most houses (assuming no shade trees, etc.).
Also it is very rare, where most live in US, that a 3000W peak power solar panel can give average of 18KWH on a mid-winter day. (That is 6 hours of no-clouds noon-day sun.) You could buy larger panel but it would not be required on summer day with clear sky. Thus, I expect your really are planning to get at least half of the energy needed from the local power company.
Why not get it all and avoid the cost of the solar panels (and cleaning the snow off them etc.)? If solar panels were necessary to burn less fossil fuel (they are not) because of CO2 production from the “de-sequestered” oil, coal and natural gas, then would it not be better for the power company to install the solar panels? They would get a better price, cost less to install and total area needed would be less and better used because of the “diversity factor” – you might not drive your 60 miles on the day your neighbor dose.
There is a reason why the power companies are not installing solar cell panel even though they can more cheaply than individuals can. – Guess what it I$. If you want to be kind to the environment, (stop de-sequestering oil) and drive cheaper, import tropical alcohol, duty free. That is solar energy too, and much cheaper way to drive on “sun power.”
Some commercial solar projects:
In its efforts to create a more sustainable community, the Las Vegas Valley Water District (LVVWD) built solar power generating systems at six facilities.
The 3.1 megawatt photovoltaic solar energy project is one of the largest ever built by a public agency in the United States.
The LVVWD Distributed Solar Array systems generates approximately 5.3 million kilowatt-hours of clean electricity per year. The electricity generated by the solar arrays supports onsite operations, including pumping operations and water-treatment processes.
The solar project was developed in partnership with Nevada Power Company and PowerLight Corporation.
Other large scale projects: http://www.energy.ca.gov/siting/solar/index.html
As you probably know, states regulate the profit margins of power companies. (Most of what they collect from customers goes to finance the capital loaned them and for operating expenses.) They get to collect a ROI (return on investment) as a slightly greater than unity factor applied to their fixed base on line. Thus, by installing solar cells they can get more profit quickly as the people pay more for their electric power - that is the way the system works. All tax payers pay more also in the subsides given to solar power industry.
It certainly does not show solar cells are the best / most economical power, but that may be the case in sunny Nevada with the various government subsidies allowed for solar power. (I am not sure but think that “thermal coal” delivered to Nevada by rail is costly and that helps solar cells too.) In Germany, the "greens" have not only blocked new nuclear plants but passed laws for the existing ones to be shut down. Germany is currently world's biggest exporter and may for a few year more be able to import the power it needs from France's nuclear generators but they are building on a sand foundation as they are also one of the leading installers of solar cell power. People need to stop distorting the economics of solar power and get realistic.
PS your last ref ( http://www.solarhome.org/solarhomegridtiesystems.html ) by chance is a 3000W peak system and priced at $17,000 when written. That capital invested at 6% gives income of $1,020 annually which at $4/ gallon gas is 255 gallons, which at 30, miles /gallon is 7650 miles. So intially it would look like the solar powered hybrid car, if not too much more expensive than a regular one, is econonomically feasible, (assuming the tax payers continue to heavily subsidize the solar cell industry), but just not as economical as one running on tropical alcohol. (Also solar powered car in fact with very proven ICE and without the need to buy new battery or fuel cells systems a few times during the 10 years of car life.)
Seveal years ago, I priced a 3000W system from Siemens at $9950. The 120W panels themselves do not cost much. It is the inverter etc. One can have a do-it-yourself system cheaper I think by getting those commercial emergency power units and modifying them. Also since Honda runs its Hybrid at 144 Volts, I wonder if we can put 10 or 12 Lead-acid sealed marine batteries in the back which will be a lot cheaper than buying extra Li-ion batteries at $9000 a piece.
Also, if you want to use solar cells to charge the Hybrid, you do not need to convert it to AC and then DC....just buy the solar panels , store the energy in a battery bank, and connect your car to it....may need some votage regulation circuit....
More on do-it-yourself power : http://www.aceguru.com/ITRC/solar1.htm
I was at a continuing education meeting the other day and sat next to a guy who says he drives a diesel volkswagon and makes his own biodiesel using waste oil from restaurants. He says he gets the waste oil for free from the restaurants that used to have to pay someone to dispose of it.
That is surprising to me. If it is the old air cooled version the engine must have had considerable modification to get the compression ratio up for no spark ignition. (I had a couple of VW during my time. First was one of the old 36HPs and it had very low compression with big cylinders - It could burn almost anything liquid and exothermic - kerosene was fine (mixed with gas for adequate vaporization), for example and untaxed as a motor fuel. Manual listed benezine, but hard to find in US, perhaps was available in Gremany?) Perhaps the modern water cooled VW are with High compression?
Some Volkswagen models have diesel engines. That is what he probably used.
This reminds me of something I was wondering this week. Your high-voltage hybrids are built like you need storage for quite a number of miles, and even so, a lot of them are not plug-ins. If they do not recharge from the wall socket, then their need for energy storage is a lot shorter term than the 50 to 200 miles, "if the engine fails or I run out of gas I can get home", type of capacity. Of course, you and I can't take a Prius and easily convert it to run on a couple of lead-acid batteries the way that some of the earlier hybrids did.
The original theory of a hybrid is that the fuel-based engine runs at maximum efficiency and the electric motor puts that energy on the ground with maximum efficiency. This included the fact that the fuel-based engine can be shut off when not needed to keep the batteries topped off and you spend no fuel while waiting at lights, which is a huge percentage of the fuel wasted on driving in town. The batteries level the load on the gasoline engine. How fancy does that have to be?
-As fancy as we'll put up with, without building our own.
Huh ? Some ?
Pretty much all models are available with diesel engines..
Not in the US. Thanks to the eco 'tards and their obsession with only exhaust emissions that are smog precursors (SO2/NOX) versus CO and CO2, all the low-displacement tubodiesels that have been sold all across Europe for years have barely been let in the door here. Thankfully that is starting to change.
It's really hard to build or service any sort of vehicle if the parts aren't standardized and available at your local parts store. Those who build their own have a daunting uphill struggle to face. Where do you even get a suitable electric motor? How do you attach it to the transmission? We are just barely reaching the stage where someone can send the right data file to a manufacturer and get a custom part made without spending thousands of dollars in setup fees, and who has those data files? That's just a machined block of metal, too, not all the tiny subassemblies that some automotive parts have.
Separate names with a comma.