Naked Science Forum
Non Life Sciences => Technology => Topic started by: Yahya on 23/11/2016 08:42:54
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I think I managed to make a working clockwork with unlimited gear stages , I think it would solve all energy problems and climate change as well , as it could store large amounts of energy cheaply and effectively, what do you think ?
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a working clockwork with unlimited gear ratios
Let's say you have a gear ratio of 1,000,000,000:1, so the "output" turns 1,000,000,000 times for each rotation of the "input".
But to deliver energy, you need two factors: Number of turns and torque (https://en.wikipedia.org/wiki/Torque) (a unit similar to "force" for rotating systems, measured in Newton-meters).
Unfortunately, the torque reduces by the same gear ratio as the rotations increases. So, under ideal conditions, the energy coming out equals the energy going in.
- Even more unfortunately, real gears have a bit of friction, so it becomes effectively impossible to turn the output without stripping the gears on the input.
store large amounts of energy cheaply and effectively
Gear trains don't usually store much energy, but you can couple energy into a large flywheel, which can store considerable amounts of energy.
- It is important that the flywheel has near-frictionless bearings.
- It would be unusual to couple energy into the flywheel using gears; more common is to use a reversible electric motor/generator and inverter circuit.
You can use the electric motor mode to spin up the flywheel, and change to generator mode to convert rotation into electrical power. The inverter circuit ensures that the mechanical speed of the flywheel can be independent of the power frequency used as the source or destination of the electrical power.
Flywheels have been used as temporary energy storage in some race cars - enough to slow the car for a corner, and then accelerate again after the corner. But most of the energy for the race still comes from the petrol tank.
Flywheels have been used to power data centers for a few seconds while the emergency generators come online. Recalling a conversation with a data center manager from early this year, I think their industrial-sized flywheels could deliver somewhere about 16 MegaWatts for 10-15 seconds until the diesel generators fired up. But most of the energy comes from mains power or the diesel tank.
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I think if you want to move a clockwork with 1000,000,000 : 1 you need ultra high energy and the input rotation frequency would be ultra high other than that it won't move at all , but I solved this problem , the input energy is what we want and megawatts can be consumed in days.
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Think of the advantages of clockwork: very high torques available at short notice, indefinite storage with no loss of power.
Disadvantages: poor efficiency of spiral springs and gear trains, poor energy/weight or energy/volume ratio for any other configuration, poor reliability in repetitive functions (OK, church clocks can run for hundreds of years, but they are grossly overspecified mechanisms for moving a couple of well-balanced hands, and require regular maintenance), not robust against mechanical shock..
There are several very good reasons why clock and watchmakers no longer use it.
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There are several very good reasons why clock and watchmakers no longer use it.
I want to build a huge one and use it for a car , or ultra huge one to store solar panel electricity by motors and convert it to electricity again by generators. could it replace batteries ?
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could it replace batteries ?
There already are clockwork radios, but they serve a very niche market where batteries are expensive or difficult to obtain, or inconvenient for some other reason.
https://en.wikipedia.org/wiki/Trevor_Baylis
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I think it would solve all energy problems and climate change as well
You seem to be proposing some form of perpetual motion machine, which puts out a large amount of energy with a small energy input?
Despite years of trying by numerous inventors, these have always failed (so far), and there are good theoretical reasons to assume that they will keep on failing. The US patent office automatically rejects any patent applications for perpetual motion machines, unless they are accompanied by a working prototype.
See: https://en.wikipedia.org/wiki/Perpetual_motion
I want to build a huge one and use it for a car
Mechanical gears with a fixed gear ratio are not a good way to spin up a flywheel.
You want to make the flywheel go faster while the car is slowing down (and vice-versa); fixed gear ratios don't work that way!
A continuously-variable transmission is capable of the right behavior, but they are mechanically more difficult to make.
the input energy is what we want and megawatts can be consumed in days
There seems to be a problem with the units here.
- A flywheel stores Energy; scientists measure Energy in Joules.
- Appliances consume Power; this is measured in Watts=Joules/second.
- Energy = Power x Time.
- Input Energy = Output Energy (+ losses)
- You can inject the energy quickly over a short time, or slowly over a long time. But the rate is limited by the Power rating of the device.
Take the example of a big flywheel system that can deliver 16 MW for 15 seconds:
- The Energy stored is 16MW x 15s = 240 MJ
- These devices weigh many tons, and spin at very high speeds
Contrast that with the proposal above:
- I think you are proposing a device that could deliver (say) 2MW for 2 days
- Its energy storage = 2 MW x 200,000s = 400,000 MJ
- To be small enough to put in a car, it can't weigh more than 1 ton = 1,000kg.
- The energy density would be 400,000 kJ/kg, which is enormous!
- If this car were ever involved in an accident, you would be sitting on an enormous bomb!
Two figures that people focus on for energy storage are:
- Energy Density: kJ/kg
- Lithium ion batteries as used in cars get about 500kJ/kg
- Flywheels get a little lower, around 400kJ/kg
- See: https://en.wikipedia.org/wiki/Energy_density_Extended_Reference_Table
- Power Density: W/kg
- Lithium ion batteries get about 200W/kg
- See: https://en.wikipedia.org/wiki/Power-to-weight_ratio#Electrochemical_.28galvanic.29_and_electrostatic_cell_systems
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It's not a perpetual motion device it will solve energy problems by using it at electricity plants to store large amounts of energy from solar panels , a motor will convert solar panel electricity to be stored in this clockwork as potential energy , and to be converted again by generators for cities . it will solve climate change and energy problems by replacing engines in cars.
it's not ( 400,000 ) MJ , take an example of a car that consume 2.5 KW with say 90 Km / h speed , for one charge of this clockwork it can go for about 2.2 hours for 200 Km , the total energy is only 20 MJ .
the large amount of energy (400,000 MJ ) is for electricity plants.
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The automotive flywheel, if the energy density figure given above is correct, would seem technically feasible, but to have a weight comparable to an equivalent lithium-ion battery it would have to be of large diameter, which presents problems, or spin at very high speed, which is dangerous, or both. Also, there is the problem of energy loss to friction if the vehicle sits stationary for a while while the flywheel keeps spinning. Also, given the necessary size and speed, gyroscopic issues would be non-negligible. They could make steering very difficult. There are ways of mounting to nullify this, but that adds a lot of bulk. As for using a flywheel to store utility-scale energy: that is less infeasible in the sense that some of the problems that apply to the automotive case would not apply. I don't know if in that use it might actually be cost-effective compared to batteries. I am, however, wondering about the friction question.
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Automotive applications aside, one thing that makes the flywheel especially attractive for utility-scale projects is that the possible energy density per kilogram is not fixed, but is limited only by the possible linear speed. The possible linear speed increases as the radius increases, because the mass moves in a less tight curve. Mass increases with radius, and energy increases as the square of the linear speed. All this strongly favors large flywheels for serious energy storage. The major issue is friction: to store energy over an extended period of time, such as overnight, the friction must be low enough that it does not seriously slow the wheel over that time interval. That gets harder to do as the weight of the wheel increases. How would it be suspended? Roller bearings come to mind, but I doubt they would be up to this job. Magnetic levitation provides an ideal solution in theory, but finding magnets strong enough to levitate a seriously heavy wheel could be difficult. Another possibility is pressure lubrication: a fluid pumped between bearing surfaces keeps them from touching. However, the fluid probably has viscosity, which must be taken into account. The least viscous common fluid that comes to mind is air. The wheel could float on a cushion of compressed air. However, this requires a compressor, which consumes power. The one thing I can think of that might solve this problem is superfluid helium.