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Is there anything known as a Heat conductor

  1. Jul 3, 2013 #1
    All the metals are generally good conductors of heat.

    But is there a conductor for heat which drives heat without deviating or diverging through a fixed path as copper wires conduct electricity.
     
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  3. Jul 3, 2013 #2
    I don't understand the question - if you put a heat source at one end of a copper wire eventually it will conduct and diffuse its way through the wire, if the wire is properly insulated to prevent too much loss.
     
  4. Jul 4, 2013 #3
    Well insulated heat-pipes are the first thing that popped into my mind, as the conduction is very good and the loss is very low...depending on some factors. But as dipole said a simple insulated wire is also heat conductor, albeit perhaps not nearly as good. It will conduct much more slowly, but exactly how much heat "deviates" from the path will depend largely on the insulation. There will probably always be losses in the form of heat. Even an electric wire has losses in the form of heat.
     
  5. Jul 4, 2013 #4
    Heat will move from a higher temperature to a lower temperature by conduction, convection, or radiation.
    There is no such thing as a perfect conductor of heat nor a perfect insulator.
    You also cannot store heat as the temperature of the body will eventually become the same as its surroundings.

    One can transfer heat from one specific location to another specific location by several methods:
    1. Transfer through a solid - heat will move from the higher temperature end to the lower temperature end, and as dipole mentioned, for efficiency the solid has to be insulated from the environment, although this may be fine for short distances. Conduction would be the prime mover of heat.
    2. Enclose a fluid, gas or liquid, in a confined pipe, in which case, conduction and convection would be the means of heat transfer. Radiation may or may not be negligable.
    3. Move a mass of heated fluid from one location to another by enclosure within in a pipe. Raise the temperature of the fluid at one end and by means of a prime mover such as a pump, and transfer the heated fluid to another location. The system can be even closed loop such as the cooling system in your car, or open loop such as the water heater in your house to supply hot water to your tap, through the copper pipe. For long distances this is more efficient than items 1 or 2.
    4. Use directed radiation. Beam divergence may be a problem.

    Depending upon the mathematical model and system, the conduction of heat can approach that of through an idealized 'conductor' to some extent, but will never be achieved.
     
  6. Jul 4, 2013 #5

    CWatters

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    Silica aerogel has interesting thermal properties (but not quite the one you were asking about)...
    http://energy.lbl.gov/ecs/aerogels/sa-thermal.html [Broken]

    I suppose if you could shape the pores you could make a material that conducts heat better in one plane than another?
     
    Last edited by a moderator: May 6, 2017
  7. Jul 4, 2013 #6
    My main objective of the question was, when I have simultaneous heating and cooling on either junction a of a material as in Peltier effect, I need to extract the heat and cold temperatures separately for further use. The problem here is very quickly the hot and cold temperatures cancel out each other.
    Is there anyway I can successfully transfer the heat?
     
  8. Jul 5, 2013 #7

    Drakkith

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    What do you mean they 'cancel out'? The peltier effect should remove heat from the cold side, and dissipate it on the hot side.
     
  9. Jul 5, 2013 #8
    Yes, Peltier effect produces heats one side and cools other side.

    But, when I remove the supply, The temperature from the hot side heats the cold side.

    To explain it numerically, When I apply a voltage V to a Peltier module, heat is dissipated at one side and absorbed on the other. Let us say that the temperature at one side is 200 C and temperature at the other side is -200 C.

    When I remove the supply, the temperature at both the sides become 0. I need to separate 200 C and -200 C for further use.
     
  10. Jul 5, 2013 #9

    Drakkith

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    Can't be done. The two sides are touching. Without a constant voltage both sides will simply return to equilibrium. You have to use the temperature difference while the device is active. At best you could store the heat in another object that's attached to each side, but you're still limited by the amount of heat the device can pump per unit of time.
     
  11. Jul 7, 2013 #10

    CWatters

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    The only way to do it is to remove the Peltier effect device and replace with insulation.

    There are systems that move heat only one way. For example a home central heating system will move heat from the boiler/furnace to the rads, which can be some distance away. Turn off the circulating pump and not much heat will flow back the other way. Lots of variations on this theme exist.

    You cannot do it without expending energy. It can be tricky to get your head around but..

    http://en.wikipedia.org/wiki/Maxwell's_demon
     
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