Please turn on javascript in your browser to play chess.
Science Forum

Science Forum

  1. 24 Aug '10 15:53
    It occurred to me that if a carbon nanotube that was shaped as a coil then it could be made to make shock absorbers. So I searched the net to see if anyone else had thought of this and found:

    http://www.engadget.com/2008/08/14/shock-absorbing-carbon-springs-to-protect-falling-gizmos/

    But then, to my surprise, I found that carbon nanotube springs can also be used to store energy with an energy density similar to that in the best lithium batteries! :

    http://www.nanowerk.com/news/newsid=12701.php
  2. 25 Aug '10 06:29
    Originally posted by Andrew Hamilton
    But then, to my surprise, I found that carbon nanotube springs can also be used to store energy with an energy density similar to that in the best lithium batteries!
    Cool.
    So 50 years from now, I will be winding up my alarm clock, but it will have a carbon nano-tube spring system and I can wind it up once and it will run for the whole year.
    I will also be able to wind up my digital camera by hand, and using my exercise bicycle wind up my laptop.
  3. 25 Aug '10 08:13 / 1 edit
    Originally posted by twhitehead
    and using my exercise bicycle wind up my laptop.
    I hadn’t thought of that one.

    Could extend that idea:

    Perhaps all the exercise equipment in gyms can be hooked-up to electric generators that generate and then feed electric power to the electric grid as people exercise?
    -so you can keep yourself fit and reduce carbon emissions and benefit the energy economy all at the same time.
  4. Subscriber Proper Knob
    Cornovii
    25 Aug '10 11:33
    Originally posted by Andrew Hamilton
    I hadn’t thought of that one.

    Could extend that idea:

    Perhaps all the exercise equipment in gyms can be hooked-up to electric generators that generate and then feed electric power to the electric grid as people exercise?
    -so you can keep yourself fit and reduce carbon emissions and benefit the energy economy all at the same time.
    I've thought about this for a while.

    A friend of mine at my old gym once suggested to the management the idea of hooking the cardio machines up to electric generators which could then contribute to the electric for the lights. They looked at him like he'd just dropped out the sky.

    My idea is to have all prisoners on electric generating bicycles for a certain amount of time a day. Part of their debt to society can be the production of electricity.
  5. 25 Aug '10 18:26 / 1 edit
    Originally posted by Andrew Hamilton
    Perhaps all the exercise equipment in gyms can be hooked-up to electric generators that generate and then feed electric power to the electric grid as people exercise?
    -so you can keep yourself fit and reduce carbon emissions and benefit the energy economy all at the same time.
    It sounds good, but if my experience with dynamos on bicycles is anything to go by, the output would be negligible. It probably wouldn't even be enough to provide the lighting for the gym. Don't even think about heating the pool.

    A more environmentally friendly building such as more glass to allow daylight in, would have a bigger impact on carbon emissions.

    If you really want to have an impact, then close down the gym and exercise by other methods (jogging, cycling outside etc).
  6. Standard member joneschr
    Some guy
    25 Aug '10 19:00 / 1 edit
    I don't think dynamos on bikes is a good example. The goal there is to light your bike light without introducing any extra effort to the biker. The biker wants to worry about gravity, not your dynamo.

    In the gym its different. The exercise equipment slows the "biker" down with friction to give the biker some work to do. That might as well be put to good use rather than wasted friction.
  7. Standard member joneschr
    Some guy
    25 Aug '10 19:03 / 1 edit
    This guy generates 300 watts and he's 55 years old. Definitely not insignificant.

    http://www.los-gatos.ca.us/davidbu/pedgen.html
  8. 26 Aug '10 04:48
    Originally posted by joneschr
    This guy generates 300 watts and he's 55 years old. Definitely not insignificant.

    http://www.los-gatos.ca.us/davidbu/pedgen.html
    I generate 200 W constantly, even when I'm sleeping. That's my body temp that generates that.
  9. 26 Aug '10 09:39
    Just had an idea:

    When a wind turbine is collected a lot of power from the wind at a time when there is a lack of demand for electricity, perhaps rather than generate electricity it could store that mechanical energy in a nano-spring -unit (if I may call it that) in the wind turbine and then later on when there is no wind but high demand for electric power the mechanical energy in that spring-unit could be used to drive the electric generator of the wind turbine but without turning the blades.

    -this would be a complicated setup but it would efficiently albeit partly overcome one of the limitations of wind power.

    The same idea could also be used for wave power and tidal power and run-off-the-river hydroelectric thus avoiding building dams for the hydroelectric power?
  10. 26 Aug '10 19:21
    Originally posted by Proper Knob
    I've thought about this for a while.

    A friend of mine at my old gym once suggested to the management the idea of hooking the cardio machines up to electric generators which could then contribute to the electric for the lights. They looked at him like he'd just dropped out the sky.

    My idea is to have all prisoners on electric generating bicycles for ...[text shortened]... tain amount of time a day. Part of their debt to society can be the production of electricity.
    http://en.wikipedia.org/wiki/Electrical_generator#Human_powered_electrical_generators

    The average adult could generate about 125-200 watts on a pedal powered generator.
  11. 27 Aug '10 11:38
    Originally posted by joneschr
    This guy generates 300 watts and he's 55 years old. Definitely not insignificant.

    http://www.los-gatos.ca.us/davidbu/pedgen.html
    It is definitely insignificant. Thats three light bulbs. For the period that he is peddling only. Its not even enough to run a computer (assuming you don't spend all day exercising).

    As I said, you probably couldn't even keep the gym lights going.
  12. 27 Aug '10 11:42
    Originally posted by Andrew Hamilton
    When a wind turbine is collected a lot of power from the wind at a time when there is a lack of demand for electricity, perhaps rather than generate electricity it could store that mechanical energy in a nano-spring -unit (if I may call it that) in the wind turbine and then later on when there is no wind but high demand for electric power the mechani ...[text shortened]... ould be used to drive the electric generator of the wind turbine but without turning the blades.
    The apparent advantage of the nanospring is not so much its efficiency, but its energy density. The main use of high energy densities is in portable equipment.
    I think there are probably more efficient (and significantly cheaper) methods of storing power than nano-springs.
  13. 27 Aug '10 14:41
    Originally posted by twhitehead
    The apparent advantage of the nanospring is not so much its efficiency, but its energy density. The main use of high energy densities is in portable equipment.
    I think there are probably more efficient (and significantly cheaper) methods of storing power than nano-springs.
    I wasn’t aware of the nanospring recharge-discharge ( if I may call it that ) efficiency.
  14. 28 Aug '10 14:27
    Originally posted by Andrew Hamilton
    I wasn’t aware of the nanospring recharge-discharge ( if I may call it that ) efficiency.
    I don't know what the efficiency is. What I do know is that your first post points out its energy density. The main reason why we want high energy density is for use in portable batteries. This could include cameras, laptops, phones and even cars. High energy densities are not really that important for large scale power storage. What is important there is the recharge discharge efficiency. Unless that is unusually high for nano-springs, there is no real reason to think they would be any more useful than current methods - which include things like storing heat in molten salt, or pumping water up a hill.

    I also found it interesting that your first thought was to replace hydro-electric dams. Surely if we find better power generation methods, the first to go should be coal plant and other fossil fuel based power generation? Then maybe nuclear power next. Hydro-electric remains one of the most environment friendly power generation methods there is.
  15. 28 Aug '10 18:17
    Originally posted by twhitehead
    I don't know what the efficiency is. What I do know is that your first post points out its energy density. The main reason why we want high energy density is for use in portable batteries. This could include cameras, laptops, phones and even cars. High energy densities are not really that important for large scale power storage. What is important there is ...[text shortened]... Hydro-electric remains one of the most environment friendly power generation methods there is.
    “....Surely if we find better power generation methods, the first to go should be coal plant and other fossil fuel based power generation? ...”

    yes, of course.

    “...Then maybe nuclear power next. Hydro-electric remains one of the most environment friendly power generation methods there is. ...”

    You may have misunderstood me just slightly; I agree with everything you say here but although Hydro-electric remains one of the most environment friendly power generation methods it comes in two forms; the one most often used involves the building of dams and the other sort doesn’t store potential energy in dams but simply takes the kinetic energy of the river as it comes and is called “run-off-the-river” hydroelectric (you can Google this). Out of the two, the run-off-the-river type is generally by far the most environmentally friendly mostly because it doesn’t involve building dams that can result in vast areas of forest or valuable property being flooded behind the dam. It also has other advantages such as the much lower capital costs; building dams is very expensive (not to mention time-consuming)!
    But; unfortunately, its really big disadvantage is that it doesn’t store potential energy. Now if only we can find an economic alternative way to store that energy that is as good but cheaper than using dams, that could be a huge potential improvement to hydroelectric in the future.