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The Neverending Powersource Answered

Energy has to come from somewhere. A motor, when turned, creates electricity from the terminals. When electricity is applied to the terminals, the motor shaft moves. Backwards compatibility, anyone? The sun constantly gives off energy. The suns energy is used to grow food. Continuing on with the theory. So, in this example, energy came come from the sun, which goes into plants. Now, we can make the plants into ethanol, however, the amount of energy burned from ethanol is almost equal to that producing it. BUT, if we do not use the plants to make ethanol, humans can eat it. That, in turn, lets us function and work. Now, do you know what the near neverending powersource is? Do you? Animals. Humans in particular. So, to create electricity, we need some form of generator that creates electricity when work is applied to the generator. Hmm... I know! A bike generator! A human pedaling a bike generator that is connected to a motor creates electricity. Basically, we are more efficiently harnessing the suns rays. Yes, I have accounted for the amount of energy it took to produce the bike, motor, and other unneccessary accessories humans MUST have on that bike. But eventually, We may overcome the amount it was needed to produce those things. So, I will soon be creating an instructable on a bike generator, created from your previous/preexisting bike, that will be very simplistic to create and easy enough a 12 year old could do it. Remember, humans can harness the suns power even more effectively than other sources of green power. (I know this will cause a disruption in the comments, but so far, Nuclear is the cleanest, however the waste is not very good...)


Im glad this struck some comments. Most, if not all were informational and brought me into the "Laws Of Therodynamics and Superconductors!" Thanks All! -RoAr

[ missed this comment when you first posted it... ] You're welcome! You can tell that there's a small group of us who really enjoy these sorts of discussions. And for the educators (me, Kiteman, maybe others) there's the satisfaction of seeing someone else make new connections in their knowledge.

If you're talking about harnessing human activities to generate power, that is already being worked on.

Some club dance-floors use the pounding of dancing feet to generate electricity. Fabrics have been designed to turn bodily motion into tiny currents that could trickle-charge a phone, I posted a topic some time ago about a generator that attaches to the human leg, harnessing the flexing of the knee to generate electricity.

There is even a watch that runs on electricity generated by exploiting the difference in temperature between your skin and the air around you.

But... an efficient way at harnessing the Sun's energy? Hardly! Since both plants and humans run at a smidge over 30% efficiency, we'll be generous say that the devices do as well - that's 30% of 30% of 30% = not a lot.

Granted most perpetual watches seem to work really well with a simple generator from motion, I say perpetual because that's the general name, I'm not losing my mind.

I'm not saying it doesn't work, I'm saying it's not an efficient way of harnessing solar power.

I know, even the best of PV cells aren't particularly effective...

Let me rephrase that: --Another-- way to use the energy, instead of wasting it on just say, running, as in exercise. This is a way to actually make energy with the energy used for running, in this example. It's another way, thus increasing efficiency of overall use of the sun. Does that make it slightly clearer? That's pretty cool about the dance floors and fabric. -RoAr

Oh, we still talking about the same thing, as some gyms have started using their equipment to generate electricity.

you can break even, kinda superconductors, if it's cold enough

I didnt get the past 3 post. What cant break? The law? The theory? What is about superconductors?

superconductors are conductors with 0 resistance, but then need to be kept at like temperatures below 92 kelvin (liquid nitrogen boils is 77 kelvin, just so you know) 0 means 0 resistance, it's a perfect conductor

Yes, but "below 92 kelvin" is a far cry from 0 kelvin. You cannot reach temperatures of 0 kelvin. You can come close, but never attain it, as you can never attain C.

0 kelvin = -273.15Celsius
77 kelvin=-196.15Celsius
92 kelvin = -181.15Celsius

Liquid nitrogen is used to cool it down.

I'm sorry, I fail to see the relevance of that...the fact is that it is cold, but never attains 0 K, and so never breaks even.

a certain type of superconductor reaches superconductivity at 92 kelvin. it's 100 percent efficient I don't get what's the problem here how is reaching 0 kelvin breaking even?

Please read some basic physics textbooks, in particular the chapters on thermodynamics. If you don't understand the concepts, it will be very difficult for you to discuss them rationally.

hey, don't talk down to me What's so hard to understand about something 100% efficient? Superconductors are litteraly 100% efficient. You could induce a current on a loop of superconductor and the electricity will flow indefiniteley until stopped by a load/break in the line. They are use in modern day life, they are replacing huge underline cables with smaller, thinner superconductors to carry the same amount of current (like, instead of having 20 heavy copper wires, they have 1 superconductor wire). It's not like it's creating energy or anything. It does take energy to keep it at that temperature if the surroundings are warmer, though

Your "modern day life" example is factually wrong on several points. No one is replacing existing powerlines with superconductors.

The existing superconducting materials which can be formed into strong wires and carry high currents all require liquid helium (that's 4K) for cooling. The energy required to maintain a liquid helium/vacuum dewar system is far, far, FAR more than the losses due to ohmic heating and voltage drop in convential AC lines.

The new "high-temperature superconductors", which can be cooled with liquid nitrogen, have two problems. First, they are ceramic not metal, and cannot be formed into robust, flexible wires while still maintaining the crystal structure needed for superconductivity. Second, they cannot carry sufficient current to substitute as power lines, without losing their superconductivity.

One clarification to my third paragraph above. I said that the high-Tc ceramic superconductors "cannot be formed into robust, flexible wires." In fact, there is industrial research on-going, with substatial progress in making "thin film" strips rather than conventional wires. I don't know how well that research has been commercialized (Google Is Your Friend), but in any event, moving from wires to flat ribbons would have substantial ramifications for the whole industry.

You are still confusing superconductivity with thermodynamics. We are talking past each other, not at each other. This whole thread is based on thermodynamic principles; superconductivity isn't relevant to the thread, which is why the rest of us are really confused about how your comments (while true) relate to anything else being discussed.

Yeah, I don't feel like we're talking about the same thing :P I was just giving an example of something that was 100% efficient because Adrian Monk said you couldn't

It is not possible in this universe to build a heat engine (any device which extracts work from a temperature difference), or more generally from a flow of energy between a source and a sink, which is 100% efficient. Thermodynamic cycles increase entropy on each cycle, which results in less than 100% efficiency.

Superconductivity is not a counterexample, because the circulating supercurrent cannot be used to perform work. If you do -- either to do something like power a light bulb, or to use the generated magnetic field to move an object around -- then the circulating supercurrent will be reduced, by exactly the amount corresponding to the energy you extracted as work.

you can build "heat engines." There are some very very expensive fragile clocks that work on the principle that it's cooler at night and hotter during the day, and they use this temperature differential to wind themselves. Also, Peltier-junctions work on temperature differental or are you talking about 100% about those above, I couldn't tell how that was tacked on. I opened a door I now regret, lol I'm just going to kind astop now, with all due respect

Don't regret it. I'm sorry the discussion went awry because of misunderstanding. Both thermodynamics and superconductivity are interesting topics, each with their own subtle details (and wrongheaded popular mythology). Almost all our non-electrical mechanical devices are heat engines. The engine in your car, steam turbines, Stirling engines, non-electric heat pumps, all work on the principle of thermodynamic cycles. The less than 100% efficiency I'm talking about (and what we all mean) is the ratio of useful work (force times distance, or torque to your wheels, or whatever) you get out of a heat engine on one cycle, divided by the total energy used to drive the engine around that cycle (heating the water batch, burning the gasoline, whatever). Does that help clarify things?

Perhaps I should open another forum topic and ctrl+C+V all of the above?

(This isn't relevant to the topic but) Superconductors are most commonly cooled by liquid helium, e.g. as used in the LHC. L

Ive read in before or later comments that you can alos use liquid nitrogen? Perhaps hydrogen, no matter how flammable...

Hi, RoAr. Put simplistically, there are two broad classes of superconductors. Classic "BCS" superconductors (like lead, niobium titanate, and so on) only reach their superconducting phase at temperatures extremely close to absolute zero, typically around or below liquid helium temperatures. All of these are metals (elements or alloys). In the late 1980's a new class of ceramics based on rare earth elements (the so-called "YBCO" and related materials) were discovered which become superconducting at substantially higher temperatures, around or even above that of liquid nitrogen.

Liquid nitrogen boils at 77K, liquid helium boils at 4K.

Adrian Monk: "You can't break even" is a colloquial way of stating the second law of thermodynamics, that you cannot achieve 100% efficiency in any system. boom, 100% I agree it never reaches absolute zero, I was only talking about the first law also, I'm pretty sure "you can't reach absolute zero" is the third law, but I don't feel like looking it up.

Boom, 100%? I don't understand what you are saying at all. I was saying that the second law of thermodynamics, which states that you can never reach 100 % or more efficiency, cannot be broken. You are correct in saying that the third law explains that you cannot reach 0 K, but that was not the law I was referring to (yet).

"You can't break even" is a colloquial way of stating the second law of thermodynamics, that you cannot achieve 100% efficiency in any system. The second law of thermondynamics cannot be broken. You can't reach absolute zero (0 K, −459.67° F, −273.15° C ), so talk of superconductors are irrelevant.

Superconductors don't break even. If you try to extract power (e.g., light a light bulb) using a superconducting wire, you will extract energy from it and the current will be reduced.

they break even, 100% is even. above is overunitiy, which seems like what you are describing

Yes, and I fully agree with what it said. I am not claiming to bring energy "Out of thin Air." I am just saying, humans basically regenerate over time, by inhaling nitrogen, which aids in help of creating/repairing muscle. They also eat plants/animals that ate plants, to recieve the energy they got from the sun.

'Basically, we are more efficiently harnessing the suns rays.'


Actually, we're very inefficient if you compare to just plants. The more the energy is processed, the more is lost. Take your example of generating energy from a human powered bike. It's powered by you, who if you are like the vast majority of people, eats a good deal of animal products, say a grazing cow. You eat the cow, which eats grass, which directly takes in solar energy. So the energy comes from man on bike<cow<grass<sun. The further removed you are from the primary harvesting of solar energy, the more energy loss there is. Sure, the nitrogen cycle recycles nitrogen, but that dosen't have to do with the sun's rays. Plants are far more efficient at using the sun's energy.

But you are correct in saying that humans harness the sun's rays. It just isn't more efficient to do it this way than to do it directly (technology limits aside, I don't know how efficient solar cells are these days).

Isnt it better than a person just standing? Doesnt a bike generator stop people from watching TV, using fossil fuels/suns energy to create the electricity needed to power it? -RoAr

Of course it's an awesome idea! I'm just saying that it's not more efficient, and won't "overcome the amount it was needed to produce those things". But I love the idea, I'm working on one myself. :)

How do you do italics? I know there is a BB script instructable, but I dont want to waste time. -RoAr

Are you able to qualify your statement in bold? And by that I mean give some proof, evidence, or citation which supports it? L

Isnt it better than a person just standing? Doesnt a bike generator stop people from watching TV, using fossil fuels/suns energy to create the electricity needed to power it?


Let me rephrase that:

--Another-- way to use the energy, instead of wasting it on just say, running, as in exercise. This is a way to actually make energy with the energy used for running, in this example. It's another way, thus increasing efficiency of overall use of the sun. Does that make it slightly clearer?

I meant to do it in italics, but I hae not looked up the BB script instructable yet.