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Thread: If heat is the 'lowest' grade of energy,What is the highest?

  1. #1 If heat is the 'lowest' grade of energy,What is the highest? 
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    It seems rather intuitive to say that heat is the lowest form of energy, simply because it seems to be the hardest to convert into other types (in terms of efficiency), But is there an actual order in which forms of energy may be listed by their grade?

    If heat is on the bottom, what is directly above it? What is on top?

    Why?


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  3. #2  
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    I don't know............. what are you talking about?


    Beyond Equations,

    Pritish
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  4. #3 Re: If heat is the 'lowest' grade of energy,What is the high 
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    Quote Originally Posted by cryptonic26
    It seems rather intuitive to say that heat is the lowest form of energy, simply because it seems to be the hardest to convert into other types (in terms of efficiency), But is there an actual order in which forms of energy may be listed by their grade?

    If heat is on the bottom, what is directly above it? What is on top?

    Why?
    Who says heat is the 'lowest' form of energy anyway?

    Heat is just 'another' form of energy, and is in fact just a summation of kinetic energy (see Boltzman etc), that is also associated with wavelengths of light (because energy levels are quantised). There is nothing low or high about it.

    In engineering terms, low grade heat (a different matter altogether that might simply refer to a low heat differential ) is not frightfully useful and becomes waste in a system, but that's just the second law for you.
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    E = hf
    f is small in case of heat "infra red"
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  6. #5  
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    Quote Originally Posted by PritishKamat
    I don't know............. what are you talking about?
    I was referring to the fact that you can convert a unit of energy only so many times, until it reaches equilibrium with it's environment due to the effects of entropy. You can jump into and out of heat as an energy carrier, but you'll always end up with heat losses in that conversion. Until your unit of energy as an unusable unit of heat, spread out evenly across your system where it rests at equilibrium.. never to be converted again..

    Quote Originally Posted by sunshinewarrior
    Who says heat is the 'lowest' form of energy anyway?
    Once your energy is distributed evenly across a closed system as heat, it can't be converted into anything else, (as far as I can see). That would make it the lowest form of energy... wouldn't it?

    To make my point a little more clear, we could look at a closed system of two connected hydrogen gas chambers (Ideal, in that the chambers themselves aren't actually part of the system). They are at equilibrium with both chambers being of the same pressure; Even if it is a relatively high pressure of 20bar. That atomic hydrogen will decay eventually, releasing heat, until there is nothing left but heat itself.

    Heat seems to be the last possible form of energy (manifested as EMF), and I can't see it as being convertible at that point...

    So I'm the one who says heat is the lowest form of energy, by limited observation. I would gladly accept an illustration or example of a closed system that won't eventually come to total equilibrium as nothing but heat.



    An illustrative example of the order of forms of energy would be the conversion of an electrical potential to heat. That would be 100% efficient.. But converting that heat back into an electrical potential creates significant heat energy losses.

    So, electrical energy is above heat energy in terms of conversion efficiency. It's hard to say exactly where in a list it would belong... but this is the concept I'm exploring.


    Though, I think raed is spot on here, especially if I read into the equation a little more than is intended... Looking at conversion systems that produce heat losses at a specific quanta; I suppose an index could be listed by order of that quantitative heat loss rate.

    Theoretical conversion efficiencies from one form of energy to heat should produce an actual index value that could be listed by grades of usable energy.

    Thanks for helping me brainstorm this out guys.
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  7. #6 Re: If heat is the 'lowest' grade of energy,What is the high 
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    Quote Originally Posted by cryptonic26
    It seems rather intuitive to say that heat is the lowest form of energy, simply because it seems to be the hardest to convert into other types (in terms of efficiency), But is there an actual order in which forms of energy may be listed by their grade?

    If heat is on the bottom, what is directly above it? What is on top?

    Why?
    I have never heard that heat is the lowest form of energy. I don't even think you could imply something like that without clarifying what matter is, and what heat is. And then clarifying what electricity, sound, light, mechanical energy is.


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    William McCormick
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    Quote Originally Posted by cryptonic26
    Quote Originally Posted by PritishKamat
    I don't know............. what are you talking about?
    I was referring to the fact that you can convert a unit of energy only so many times, until it reaches equilibrium with it's environment due to the effects of entropy. You can jump into and out of heat as an energy carrier, but you'll always end up with heat losses in that conversion. Until your unit of energy as an unusable unit of heat, spread out evenly across your system where it rests at equilibrium.. never to be converted again..

    Quote Originally Posted by sunshinewarrior
    Who says heat is the 'lowest' form of energy anyway?
    Once your energy is distributed evenly across a closed system as heat, it can't be converted into anything else, (as far as I can see). That would make it the lowest form of energy... wouldn't it?

    To make my point a little more clear, we could look at a closed system of two connected hydrogen gas chambers (Ideal, in that the chambers themselves aren't actually part of the system). They are at equilibrium with both chambers being of the same pressure; Even if it is a relatively high pressure of 20bar. That atomic hydrogen will decay eventually, releasing heat, until there is nothing left but heat itself.

    Heat seems to be the last possible form of energy (manifested as EMF), and I can't see it as being convertible at that point...

    So I'm the one who says heat is the lowest form of energy, by limited observation. I would gladly accept an illustration or example of a closed system that won't eventually come to total equilibrium as nothing but heat.



    An illustrative example of the order of forms of energy would be the conversion of an electrical potential to heat. That would be 100% efficient.. But converting that heat back into an electrical potential creates significant heat energy losses.

    So, electrical energy is above heat energy in terms of conversion efficiency. It's hard to say exactly where in a list it would belong... but this is the concept I'm exploring.


    Though, I think raed is spot on here, especially if I read into the equation a little more than is intended... Looking at conversion systems that produce heat losses at a specific quanta; I suppose an index could be listed by order of that quantitative heat loss rate.

    Theoretical conversion efficiencies from one form of energy to heat should produce an actual index value that could be listed by grades of usable energy.

    Thanks for helping me brainstorm this out guys.

    I can take a long piece of steel, heat it and fasten it between two other pieces of steel, and bend both or one of them with tons and tons of force as it cools.

    It is actually a common problem in welding.


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    William McCormick
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  9. #8  
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    Quote Originally Posted by cryptonic26
    Heat seems to be the last possible form of energy (manifested as EMF), and I can't see it as being convertible at that point...

    So I'm the one who says heat is the lowest form of energy, by limited observation. I would gladly accept an illustration or example of a closed system that won't eventually come to total equilibrium as nothing but heat.
    Ok. I think I see where you're coming from.

    One thing to watch out for is the unnecessary reification of the concept of heat. It is a very useful idea, but as you yourself point out, it is actually what we measure when we are talking about either kinetic energy or electro-magnetic energy.

    Yes, the so-called heat death of the universe will manifest itself in very low energy electro-magnetic radiation as an endpoint - that's what COBE demonstrated. If that's the point you're making then that's fine - but it would then be more precise to refer not to heat, but to low energy electro-magnetic radiation - because that would indeed be the final form of all energy (and matter, as it happens). Similarly, back to your OP, gamma radiation would be the 'highest' form of energy. I just don't know, however, if such a ranking is useful, and it may even be misleading.
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    sunshinewarrior: That's really close to what I'm looking at. And you're right, I should be looking more at low density-low energy EMF as the final resting point for energy.

    It's all a bit vague to me at the moment, but I guess what I'm trying to achieve by this mental experiment is a more in-depth understanding of the conversion properties of various forms of energy.

    If you consider a currency system, like the US dollar... A penny is a penny, and it's worth the same as any other penny, even if you have a lot of them together, but the more concentrated the penny carrier, the more useful it is. For example, we don't mind losing a penny or two in a twenty dollar transaction, because the penny represents the lowest grade of currency. But when you have only two dollars to work with, a penny becomes more significant, and losses to taxes has more impact on the effect of entropy to your wallet.

    So too, is the economy of energy.. and to gain the most benefits within the economy of energy, one should understand the value of the various forms one can manipulate.


    Such a value system, Misleading possibly.. But I'm not so sure that it couldn't be of great benefit in certain applications. We do live in a world that bends to the value of something's usefulness, rather than it's theoretical mathematical value.

    This may or may no go somewhere significant, but for the moment, it has my attention and I appreciate any input or ideas to the concept.
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    You can also heat parts up, bolt them in place and shear the bolts off as the part cools. This takes tons and tons of pressure.

    Meaning that there is still the same amount of "energy" in the part, if you want to call it energy. It would be better put as velocity tending to normalize the objects size, to what it would naturally be in a normal ambient temperature.

    The power is unbelievable, in fact I would say that the cooling process is much more powerful then the heating process in most cases.

    Because the metal is cooling and no longer is soft, and forgiving.

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    William McCormick
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    I would say that the lowest form of energy is a bit ambiguous. It could be the internal kinetic energy of the atoms, or it could be the lowest energy photon, which I'd say would be correct. I think what is often talked about though as the lowest/final form of energy is heat, i.e. after any isolated energy exchange is taken to it's conclusion you are always left with a temperature increase. This is the type of thinking that one learns in school level physics.

    As for the highest form of energy; Wouldn't that be massive matter?
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  13. #12  
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    Quote Originally Posted by cryptonic26

    This may or may no go somewhere significant, but for the moment, it has my attention and I appreciate any input or ideas to the concept.
    Well, we seem to be getting somewhere.

    It seems from this interpretation, that you are trying to define a concept of available-energy-concentration, ie, the amount of energy available for work from a particular source.

    This could be a useful concept - after all, we are all intuitively in tune with the idea of concentration - in squashes, or washing up liquids, just as much as in energy sources. But there is a pitfall...

    The efficiency with which you can use energy depends in general less upon the source of energy, and more about the state of your technology (I say in general because, of course, the background microwave radiation is at such a low temperature it is unlikely that any technology will be able to make it do any work).

    For instance, until the 1940s, Uranium was a low-concentration energy source - we could get heat, and some x-rays out of it, and we would use radioactive substances for their seeming phosphorescent properties on watch hands and so on.

    Then we discovered ways of using E = mc<sup>2</sup> to our advantage, so that today the radioactive elements represent the most concentrated forms of energy available to us.

    With modern technology we know some things about our energy use - and in particular that when using heat energy, we seem to get greatest efficiencies at a particular range of difference in heat (not necessarily just the absolute temperature of the primary energy source). Someone better versed in the physics/engineering of thermodynamic systems can talk about that, but it just makes the point that there is no single answer of scale of values of energy concentration. Rather, there is a conditional, current scale of the best energy storage devices/energy sources available to us.

    Don't know if this helps with your ideas, but them's my thinks...
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