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types of energy can we harvest? - Page 2 — Parallax Forums

types of energy can we harvest?

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  • ElectricAyeElectricAye Posts: 4,561
    edited 2013-09-11 17:04
    What we really need is a demon...
  • ReachReach Posts: 107
    edited 2013-09-11 18:03
    That was a informative video. It blows me away how smart people can be, how abstract.

    Thanks for that link electric eye it makes me want to live forever just so i can see all this unfold.
  • Heater.Heater. Posts: 21,230
    edited 2013-09-11 18:43
    ElectricAye,
    I'm just trying to figure out where the source of energy might be.
    If gravity is not a form of energy. And a bucket of water is, by itself, not a form of energy. And yet we can get energy out of a bucket of water falling....
    Does that mean the "source" of energy is the height through which it falls?

    The key word in the definition I gave is "system". There is no energy or source of energy in height, mass, or gravity. But the Earth and a rock lifted up is a system with energy stored in it (E=mgh)

    Where did that energy come from? Perhaps from me as I lifted the rock. Where did I get that energy from? Mostly from the sun via growing the food I eat. Where did the sun get it's energy from?

    Ah...you may have noticed I said there is no energy in mass. Except there is, mass can be converted to energy (E=m*c*c). Atoms are systems that can store energy. The sun is a place where pairs hydrogen atoms are joined (fused) to become Helium. Two Helium atoms have more mass than one Helium. The difference becomes all that energy we see coming from the sun.

    Where did that system of Hydrogen atoms (the Sun) get its energy come from?

    I give up. Something to do with that primal Big Bang. Ultimately nowhere. The total sum of all the energy in the universe is zero!
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-09-11 21:04
    I've heard the first and second laws of thermodynamics explained as:

    #1) You can't get something from nothing.
    #2) You can't even break even.

    As recently explained, a wind turbine takes the energy from the air resulting in slower moving air.

    The guys using coils to take energy from overhead power lines get caught because the power station notices the missing power.

    When NASA uses a planet's orbital speed to give a boost to the speed of a space probe, the planet slows down (an unmeasurably small amount).

    So when they harvest tidal movements is it degrading the orbit of the moon? Or does the tide degrade the lunar orbit the same amount whether or not the tidal energy is harvested?
  • ElectricAyeElectricAye Posts: 4,561
    edited 2013-09-11 21:23
    Duane Degn wrote: »
    ... Or does the tide degrade the lunar orbit the same amount whether or not the tidal energy is harvested?

    Tidal energies end up as heat. Check out Jupiter's moon Io. Io suffers from tidal forces so badly that its guts are heated up substantially, resulting in volcanoes of sulfur, etc.

    io_close.jpg
  • Heater.Heater. Posts: 21,230
    edited 2013-09-11 21:25
    Everything you need to know about thermodynamics is in the song by Flanders and Swan toward the end of this video: http://www.youtube.com/watch?v=VnbiVw_1FNs

    Whilst we are there this is how they looked on Broadway at that time (1964) http://www.youtube.com/watch?v=1vh-wEXvdW8
  • Beau SchwabeBeau Schwabe Posts: 6,566
    edited 2013-09-11 21:44
    "I give up. Something to do with that primal Big Bang. Ultimately nowhere." - Maxwell's demon?
    "The total sum of all the energy in the universe is zero! " - Yes, it's all about electron displacement, which does agree with Maxwell demon. I think the association of information lost was poor to this video, the "demon" only needs to follow a simple rule without having to memorize each particle.

    When I give a demonstration about electricity to the kiddo's at school, I first bring out the Toppler Holtz machine explaining that there are always the same number of electrons in the system, but what this machine does is displace the electrons so that there is a charge imbalance. When you see a 'spark' the system becomes neutral. I then bring out my Marx generator capable of producing 1 foot sparks from a 6-cell laptop battery, and explain that this machine essentially does the same thing only it creates a much larger charge imbalance. The difference is that one is powered from hand-cranking creating an electron displacement through Triboelectric differences, while the other gets it's energy from a Chemical reaction within the battery.
  • prof_brainoprof_braino Posts: 4,313
    edited 2013-09-12 06:45
    xanadu wrote: »
    My perpetual motion machine runs on procrastination. It is 3000% efficient!
    Wind energy

    Much of this forum is powered by hot air already! Just look at my projects!
    Duane Degn wrote: »
    The guys using coils to take energy from overhead power lines get caught because the power station notices the missing power.

    I thought the power taken from power lines through the inductive lines was immeasurably small compared to the total power transmission, and indistinguishable from regular line loss. The only way it is detected is when the worker checking the lines SEE big wires stretched under the transmission lines where the cross over the guys house. And there's nothing the power company can do about it, since the guy's house was there first. At least that's the case I heard about.

    Also, harvesting methane for fuel would be a gas!
  • Beau SchwabeBeau Schwabe Posts: 6,566
    edited 2013-09-12 06:56
    "I thought the power taken from power lines through the inductive lines was immeasurably small compared to the total power transmission," - Have you ever been under one? You can hear them sizzle ... the amount of loss must be huge over the length they must transmit power. That said, with the right receiver 'tuned' to the 50Hz or 60Hz, I would think you could tap off quite a bit without any wires at all.... The caveat is if your load varies in a way that you can't track it with the tuned circuit, your usable output would diminish very quickly. Constant load regulation on the tuned circuit would be a key factor.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-09-12 07:12
    The answer is cows.

    Cows generate a tremendous amount of methane in their flatulence, and are considered a major contributor of greenhouse emissions that could lead to climate change. What we need is some kind of device that hooks up to the backside of the cow, traps this gas as it is emitted (which is nearly constantly), compresses it, and then contains it for easy collection. The methane could then be used for various kinds of energy uses.

    So, wind technology really does hold a lot of promise. Only this is a different kind of wind.

    Eat pork.. the methane is already captured as bio-gas in a digester and used to provide cooling for the pigs and maybe electricty back into the grid.

    How are you going to plumb a hose to a free range animal? Now really..........

    +++++++++++++++++
    I am still fascinated by off the grid Air Conditioning. A Stirling Engine can work. In some cases in may not be a ground/air temperature difference, but driven by a solar collector providing the high side of the Carnot Cycle.

    This really need to be done post haste for the poorer regions of the world.

    Of course the biggest problem in such regions might be the ability to afford the water to make into ice. 2 Tons of ice is roughly 2 cubic meters of water that has to be set aside.

    +++++++++++++++++
    And I am deeply offended at Prof Braino's claim that much of this forum is propelled by hot air. It is certainly not hot air, it is Virtual Hot Air.
  • skylightskylight Posts: 1,915
    edited 2013-09-12 07:51
    geothermal dig a deep hole in your back garden
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-09-12 08:17
    Tidal energies end up as heat.

    But not all of it. Some of the tidal energy does work. The earth's tides are slowing the earth's rotation. The complex equation used in an attempt to predict tidal lock includes a rigidity component.

    Also any energy harvested isn't heat. It can be used to do work or stored as chemical energy.

    When I asked this:
    Duane Degn wrote: »
    So when they harvest tidal movements is it degrading the orbit of the moon? Or does the tide degrade the lunar orbit the same amount whether or not the tidal energy is harvested?

    I was wondering if the devices used to harvest tidal energy end up changing the rigidity of the earth? When we harvest tidal energy are we really harvesting the kinetic energy of the earth's rotation (and causing the earth to slow down faster)?

    I'm not arguing against harvesting tidal energy, I'm just curious about the effects.

    Edit: As I think about this some more, I wonder where does the tidal energy (most of it creating heat) come from? Is the energy coming from the rotational kinetic energy of the rotating planet? I don't see how it could be anything else. I'm not so sure how true my earlier statement "some of the tidal energy does work" is.
  • ElectricAyeElectricAye Posts: 4,561
    edited 2013-09-12 08:51
    Duane Degn wrote: »
    But not all of it. Some of the tidal energy does work. The earth's tides are slowing the earth's rotation.... When we harvest tidal energy are we really harvesting the kinetic energy of the earth's rotation (and causing the earth to slow down faster)?.....

    One thing to keep in mind: the difference between kinetic energy and angular momentum. Both express the physics of motion but they are very different concepts. Kinetic energy can get transformed into other forms of energy (into heat, for example), whereas angular momentum is always conserved. I don't know how that relates to the equations you might be looking at, but it might be something to consider when evaluating planets.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-09-12 09:17
    I thought the power taken from power lines through the inductive lines was immeasurably small compared to the total power transmission, and indistinguishable from regular line loss. The only way it is detected is when the worker checking the lines SEE big wires stretched under the transmission lines where the cross over the guys house. And there's nothing the power company can do about it, since the guy's house was there first. At least that's the case I heard about.

    I was quoting what I hear from a physics instructor.

    I don't suppose you have a link to the guy who had his house there first so it was fine for him to harvest energy from the power lines? That sounds very Snopes worthy.

    My quick search of "harvesting energy from power lines" didn't turn up anything useful.

    "stealing energy from power lines" brought up some better results. This article states power companies can detect power drops from thieves. In the Snopes forum this thread discusses the issue.

    And in a one of the Mythbusters where I think "if only they had consulted a scientist" they get this experiment wrong on many levels. One of which is stating they're not doing anything illegal. (Even though they get things wrong at times, I'm a big fan of Mythbusters.)
  • Dave HeinDave Hein Posts: 6,347
    edited 2013-09-12 09:25
    The loss in the earth's angular momentum is compensated by the increase in the moon's orbital angular momentum, so the sum should remain unchanged. The reduction in the earth's rotational energy is converted to an increase in the moon's orbital energy plus the thermal and kinetic energies in the tides. If we siphon off some of the tide's kinetic energy it will eventually get converted to thermal energy after we've used the generated electricity to operate a device. So I don't think harvesting tidal energy will have much affect on the earth's rotation.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-09-12 09:25
    One thing to keep in mind: the difference between kinetic energy and angular momentum. Both express the physics of motion but they are very different concepts. Kinetic energy can get transformed into other forms of energy (into heat, for example), whereas angular momentum is always conserved. I don't know how that relates to the equations you might be looking at, but it might be something to consider when evaluating planets.

    Right, now I'm even more confused.

    I doubt it's the case, but angular momentum can be transferred to photons. I know this happens with electrons and photons but I'd be slow to suggest the change in the earth's angular momentum is being facilitated by passing it to photons. I come up with a blank in attempting to explain where the angular momentum is being transferred as the earth's rotation slows down.

    Edit: Dave Hein's post above does give me something to think about. I suppose the earth's angular momentum could be transferred to the earth/moon system's angular momentum (as Dave is suggesting). It sure makes more sense than transferring angular momentum to photons.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-09-12 09:32
    Dave Hein wrote: »
    So I don't think harvesting tidal energy will have much affect on the earth's rotation.

    I didn't think it would have "much" effect, but does it have any?
  • Dave HeinDave Hein Posts: 6,347
    edited 2013-09-12 09:40
    Sure, it will have some immeasurable effect on the earth's rotation.
  • Beau SchwabeBeau Schwabe Posts: 6,566
    edited 2013-09-12 09:57
    What if Tesla was correct? ... What if the entire Earth could be setup as a standing wave resonator in harmonic sync with the ionosphere? The analogy is like pushing a swing, it would take very little energy to keep the swing going. With this setup, power stations could feed power into the "Earth resonator" at any point on the globe as long as they "pushed the swing" at just the right moment. <- Without using wires. Likewise at any point on the Earth you could tap into this power if you were properly "tuned" to the same resonant frequency. This I believe was the essence of his vision, One of these days we might figure it out, and see that he was right all along.
  • jonesjones Posts: 281
    edited 2013-09-12 09:57
    Reach wrote: »
    Chemical reactions seem appealing to me but I am sure the byproducts are toxic.

    Not necessarily. One of the best chemical reactions for storing energy is to split water into hydrogen and oxygen. Getting (most of) the energy back requires just recombining the two back into water. If a good but cheaper catalyst can be found to facilitate the splitting, there are a lot of advantages to this. The energy can come from any renewable source but you still end up with a fuel you can store or carry around with you without needing to connect to the power grid.
  • jonesjones Posts: 281
    edited 2013-09-12 10:02
    What if Tesla was correct? ... What if the entire Earth could be setup as a standing wave resonator in harmonic sync with the ionosphere? The analogy is like pushing a swing, it would take very little energy to keep the swing going. With this setup, power stations could feed power into the resonator at any point on the globe as long as they "pushed the swing" at just the right moment. <- Without using wires. Likewise at any point on the Earth you could tap into this power if you were properly "tuned" to the same resonant frequency. This I believe was the essence of his vision, One of these days we might figure it out, and see that he was right all along.
    Isn't that sort of what Schumann Resonance is all about? IIRC lightning is basically pumping energy into a waveguide formed by the earth's surface and the ionosphere.
  • jazzedjazzed Posts: 11,803
    edited 2013-09-12 10:16
    jones wrote: »
    Not necessarily. One of the best chemical reactions for storing energy is to split water into hydrogen and oxygen. Getting (most of) the energy back requires just recombining the two back into water. If a good but cheaper catalyst can be found to facilitate the splitting, there are a lot of advantages to this. The energy can come from any renewable source but you still end up with a fuel you can store or carry around with you without needing to connect to the power grid.

    Forgot all about that! Thanks for the reminder. http://en.wikipedia.org/wiki/Fuel_cell
    NASA used Fuel Cells for the Apollo and the Space Shuttle programs. http://en.wikipedia.org/wiki/UTC_Power

    Remember what Ms Codgey O. Librarian says: 'Encyclopedias are just "starting points" for research, not final destinations, and if you donate to Wikipedia, we'll make it academic too (regardless of how badly you think we're butchering it).'
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-09-12 10:21
    jones wrote: »
    If a good but cheaper catalyst can be found to facilitate the splitting, there are a lot of advantages to this.

    A catalyst only changes the rate of a reaction. It doesn't change the equilibrium state of a system. No matter what catalyst is used, it will require more energy to split water to hydrogen and oxygen than you get back by combining them.

    It does seem like hydrogen is a good option for energy storage. There are the rare earth elements which make storing hydrogen easier. These metals absorb hydrogen gas allowing the hydrogen to be stored at lower pressures.

    When hydrogen burns you get water, but I think you can also get some smog gasses. I think with high temperature combustion, nitrogen combines with oxygen forming nitrogen oxides. So even though the theoretical product of burning hydrogen is water, it can also produce some toxic components. This is were those catalysts can really help. Rather than using a catalyst to split water (I'm not sure one exists) a catalyst can be used to combine hydrogen and oxygen without a flame. I'm pretty sure this sort of catalyst assisted burning of hydrogen is what fuel cells do. I think fuel cells are smog free.

    Edit: I see jazzed beat me at mentioning fuel cells.
  • Beau SchwabeBeau Schwabe Posts: 6,566
    edited 2013-09-12 10:24
    jones,

    Yes, but it's not controlled lightning at specific intervals. Applying man made lightning at specific intervals could create a sustained standing wave within the ionosphere but at a huge energy loss. The focus with Schumann Resonance is into the air.... Tesla tried to turn that thinking upside down and direct the energy into the Earth instead after a epiphany he had during an experiment in Colorado.

    Think about this ... The very act of a spark discharge represents an energy loss, but at the same time you can visually SEE the impressive power. The bait and switch is that everyone is memorized with big sparks flying everywhere, but fail to look the other direction. The sparks flying are the energy loss.... everyone should take a moment to look the other direction to find the energy gain or more accurately the energy source of Tesla's experiments.
  • User NameUser Name Posts: 1,451
    edited 2013-09-12 11:14
    The last information I had indicated there was more thorium along the Idaho/Montana border than there were known reserves of uranium in all the world. Thorium makes a great nuclear fuel, and can be used and reused. When it is finally spent, it can be stored in sealed copper tubes on the ocean floor, and just sit there for thousands of years - a tiny speck in a vast ocean covering 70% of the globe.

    This way no eagles or salmon are chewed up. No expensive power lines have to be strung across the desert to remote solar stations. The thorium can easily be transported to existing power plants that are already located where the power is needed.

    That's my idea for harvesting nearby energy. It would just take a little political will...
  • Tracy AllenTracy Allen Posts: 6,664
    edited 2013-09-12 11:59
    "Energy Harvesting" has a wide scale factor. These days it is often synonymous with micro-power scavenged by whatever means for things devices that would otherwise require a battery and periodic maintenance. Wireless sensor nodes, or Marty's micropower propeller from post #7 is a good example of that. Do more with less, a significant engineering challenge. This morning Mouser broadcast an email about their harvesting line. (I bet everybody here who buys from Mouser is on that list!)
  • jonesjones Posts: 281
    edited 2013-09-12 13:27
    Duane Degn wrote: »
    A catalyst only changes the rate of a reaction. It doesn't change the equilibrium state of a system. No matter what catalyst is used, it will require more energy to split water to hydrogen and oxygen than you get back by combining them.
    Of course it does. No free lunches and my use of "most" was sloppy. But if you look at the thermal efficiency of an internal combustion engine, steam turbine or whatever, we're quite used to wasting a good part of the available energy while getting what we can out of a fuel. You notice I said "storing energy". One of the big problems we have is that wind and solar are inconstant. We need a way to store power generated from inconstant sources. Hydrogen is one possibility.
    Duane Degn wrote: »
    When hydrogen burns you get water, but I think you can also get some smog gasses. I think with high temperature combustion, nitrogen combines with oxygen forming nitrogen oxides. So even though the theoretical product of burning hydrogen is water, it can also produce some toxic components. This is were those catalysts can really help. Rather than using a catalyst to split water (I'm not sure one exists) a catalyst can be used to combine hydrogen and oxygen without a flame. I'm pretty sure this sort of catalyst assisted burning of hydrogen is what fuel cells do. I think fuel cells are smog free.

    True, but it's a far cry from what we currently deal with when burning hydrocarbons and at least in some circumstances, one might just burn the hydrogen with the collected oxygen so as not to contaminate the reaction. Catalytic converters can also reduce the oxides of nitrogen. I think the efficiency of fuel cells is much higher and would be used wherever possible but companies like BMW have been looking at hydrogen as a fuel for cars so at least some uses for combustion are being considered. Regarding catalysts, I'm no chemist, but IIRC platinum works to some degree. But there are a lot of people currently looking for cheaper and better alternatives. If you believe press releases (e.g. http://www.gizmag.com/molybdenum-oxo-catalyst-for-electrolytic-production-of-hydrogen/14967/), they're making some progress.
  • skylightskylight Posts: 1,915
    edited 2013-09-12 13:32
    What happened with the "Energy from Dark Matter" that everyone was going on about a short while ago? Was it just a flash in a pan idea?
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-09-12 13:44
    jones wrote: »
    But there are a lot of people currently looking for cheaper and better alternatives. If you believe press releases (e.g. http://www.gizmag.com/molybdenum-oxo-catalyst-for-electrolytic-production-of-hydrogen/14967/), they're making some progress.

    jones, it appears you were right and I was wrong. Apparently there are catalysts for splitting water to oxygen and hydrogen. Thank you for the information.
  • skylightskylight Posts: 1,915
    edited 2013-09-12 13:50
    Splitting water makes me slightly uneasy, If we turned our water supply into making hydrogen it would be the same as turning our fields into fuel, first no food next no drinking water!

    Or can it be done without contamination or affecting the quality of water for drinking?
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