Insulators Have To Increase The Temperature At The Source

If an object is emitting heat, placing an insulator around it necessarily has to increase the temperature of the source. In order to dissipate heat as the edge of the insulator warms, the heat source also has to warm.

Heat flow is driven by differences in temperature. The insulator does not change the direction of the heat flow, but it does increase the temperature.

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55 Responses to Insulators Have To Increase The Temperature At The Source

  1. Perfect example is a light bulb in a clear glass globe and a light bulb in a black glass globe. The one in the black globe will burn out faster from a higher temperature.

  2. nickreality65 says:

    But if we consider the atmosphere an insulator, increasing it’s insulating properties via more CO2 doesn’t increase the temperature of the sun. More CO2 means more heat is held in the atmosphere, less is radiated out of the atmosphere, so the additional trapped heat must increase the atmospheric temperature. But evaporating water can absorb that heat without increasing the temperature.

    • Warren Walker says:

      Evaporating water will decrease temperature – condensing water will increase temperature. Higher temperatures from increasing heat in the atmosphere will increase radiation out of the atmosphere.

    • daveburton says:

      Nick, the “heat source” (which gets warmer) in this case is not the original source (the Sun), it is the re-radiating secondary source: the surface of the Earth.

      Just as the energy emitted by an incandescent light bulb does not originally come from the light bulb, the energy emitted by the surface of the Earth does not originally come from the surface of the Earth. In the case of the light bulb, the energy is piped in via electrical wiring. In the case of the surface of the Earth, the energy (well, much of it) is piped in via short wavelength solar radiation, to which the atmosphere is transparent.

      • bwdave says:

        Most of the shortwave energy from the Sun that reaches Earth’s surface goes into the oceans and leaves with water vapor, without significantly increasing the ocean surface temperature.

    • Actually the sun’s temperature will increase but like heating from the moon – I doubt anyone could measure it.

    • Michael 2 says:

      “But if we consider the atmosphere an insulator, increasing it’s insulating properties via more CO2 doesn’t increase the temperature of the sun”

      It would if you wrapped the insulator around the SUN.

  3. This statement is only true if the source is generating heat, not if it’s just emitting heat but not generating it.

    Put a 100 degree rock outdoors on a 40 degree day. It emits heat. If you put a blanket on it, it will slow the cooling, but the rock will never go above 100 degrees.

    • R. Shearer says:

      Yes. Another similar example is that hot coffee emits heat. Pour it into a thermos. It doesn’t get any hotter, it just cools much more slowly.

  4. Andyj says:

    Air is a superb insulator but the “GW” gasses in it either convert latent heat into radiation or vice versa.
    CO2. O3 do the opposite to the expectations of Chicken Little.


    Yin & Yan.

  5. darrylb says:

    Hey, my physics (which I taught) class all over again. My students usually were not so eager to respond. Fun to follow the dialogue.

    • Gail Combs says:

      At least ‘Deniers’ are willing to jump in and try to wade through the theory and the maths which is more effort than that most high school types expend. Warmists mostly settle for name calling.

  6. An Inquirer says:

    Fools rush in where angels fear to tread. But I am going to try an observation. I think that everybody in the discussion will agree that a blanket or an insulator keeps a heat-emitting body warmer than it would without the blanket or insulator. The objection I see is that the opponents do not see the earth’s surface as a heat-emitter. Nevertheless, I believe that the science on this issue is that the earth is a heat-emitter as it re-emits heat that it picks up from the sun.

    • A C Osborn says:

      No the Earth has no Heat Source Control, ie a continuous supply of energy to maintain the exact same temperature.
      Once the heat is gone it will be gone, only the Sun renewing the heat each day during daylight keeps the temperature the same. Turn the Sun off and see how long the Atmospheric Blanket keeps it warm.
      A Desert can lose 50 degrees C in one night, translate that to a continuous stituation, 50 degrees the first night, probably 49 or more the second day, 48 the 3rd etc.
      Eventually the only heat left to lose would be geothermal.

      • Andyj says:

        Thats what he said but an insulator or reflector only slows down the rate of loss.

        We’ve had 18 years and a month of zero GW so we can safely assume energy in equals energy out.

      • Gail Combs says:

        A C Osborn,
        Here is some real life data with CO2 but no water vapor confounding the issue.

        I see the atmosphere cooling a lot more rapidly than the sand but both cool as the solar eclipse progresses. The cooling is 10C for the air and 5C for the sand. Also the air goes from a higher temp than the sand to a lower temp than the sand. I do not see the ground being hotter than the air when the sun is shining.

    • Gail Combs says:

      I think the objection is you are counting the same energy twice and you are confusing an active vs a passive energy source. (I am not a physicist so that is the best description I have.)

      To continue the analogy –
      A living human is an energy source converting chemical energy into heat. The source of the Sun’s energy is fusion. (At least according to conventional physics Oliver.) Both of these I am defining as active energy sources since the source of their heat is dependent on chemical or nuclear reactions within themselves and not from an outside radiating source.

      Like a dead human body the IR emissions from the earth are from its TEMPERATURE and not from an acual ‘energy source’. This is what the Stefan–Boltzmann law describes.

      “…the total radiant heat energy emitted from a surface is proportional to the fourth power of its absolute temperature. The Wien Law gives the wavelength of the peak of the radiation distribution, while the Stefan-Boltzmann Law gives the total energy being emitted “ [stolen off the web]

      There is no energy source within the earth (neglecting geothermal) just as there is no longer an energy source within a dead body (neglecting decomposition)

      Chemical Enginer John Kehr who is working with The Right Climate Stuff, ‘a group of highly educated and experienced scientists & engineers from various disciplines’ many retired NASA engineers and scientists gives this correction to the Trainbreath Cartoon.

      ….This [ Trenberth’s Cartoon] is reasonably accurate, but it is also entirely misleading. The two large energy flows named Surface Radiation and Back Radiation are different from all the others. They are not measures of energy transfers, but of radiative flux (also called forcing). As I have described before, there is a difference between energy transfers and radiative flux. Two objects at the same temperature have zero net energy transfer and as a result, will not change temperature…. http://theinconvenientskeptic.com/2010/11/the-earths-energy-balance-simple-overview/

      The corrected cartoon:

      • Surely if you wanted to critique the energy flows, rather than pedantically cancelling out the radiation, you might like to consider how much effect cloud has on “back radiation”.

        To use a simple example, using a cheap IR thermometer it reads about 6C with cloud and -40C without (that’s the lowest reading). Therefore (in Scotland) the clouds are radiating like a black body at 6C.

        Trenberth has made no attempt whatsoever to describe this radiative flow in his diagram. And it is possibly the most important flow, because it is the single flow that changes most because clouds are constantly changing.

        • nielszoo says:

          Thank you. Water vapor (NOT a gas) has a measurable emissivity around 0.95. The gases in the atmosphere, between you and the cloud, do not have emissivity/absorptivity values much above 0.002 which puts them (at 1 bar) as basically immeasurable. The “back radiation” thing I always thought was kind of dumb. It is omnidirectional “radiation” and below the stratosphere is confined to particulates and water vapor.

        • Curt says:

          Clouds are NOT water vapor, and water vapor IS indeed a gas.

      • And lest I forget, Trenberth shows no heat from the earth’s core. I think it amounts to something like 0.4W, which doesn’t sound much but it is a significant proportion of the supposed** increase due to CO2.

        **The IPCC purposefully use out of date CO2 spectral data when calculating the effect of CO2.

      • RealOldOne2 says:

        Gail, re: “The corrected cartoon”,
        NASA actually shows the corrected heat flows themselves on one of their education pages: http://pmm.nasa.gov/education/sites/default/files/article_images/components2.gif

        The 324 W/m^2 or 333 W/m^2, whichever version of the cartoon you prefer is the fictional, unreal, nonsensical part. If that was a real heat flow being “Absorbed by Surface” of the Earth, you would be able to collect that heat and raise the temperature of the ‘backradiation’ collector above ambient, just as you can collect the 168 or 161 W/m^2 of solar heat that is “Absorbed by Surface”. You can’t. No such ‘backradiation’ collector device exists, even though there is allegedly twice the ‘backradiation’ heat flowing to the Earth’s surface as there is solar heat. Hmmm.
        And what a perfect energy source it would be, operating 24/7 day and night. So why hasn’t one of these perfect ‘backradiation’ collector’ been invented? Oh yeah, that pesky 2nd Law.

    • Gail Combs says:

      Trenberth’s original Cartoon

      • This makes more sense. The original Tanbooth comic strip showed 40 W of terrestrial IR going out through windows compared to 396 W being absorbed by the atmosphere. That’s only around 10%. It is unbelievable that the IR going through windows is only 10% of the upwelling. The corrected graph shows 40 out of 63 which I find totally credible. That’s more than half.

      • Edmonton Al says:

        And look at the back radiation. 333 vs Incoming solar of 161.
        Back radiation double solar?????????????
        Can a sane person believe this?

        • Gail Combs says:

          Yeah, that one really suck in my craw. It is because the sun only shines 1/2 the time or so they say while back radiation happens all the time.

          They are using arithmetic instead of calculus in that diagram.

        • nielszoo says:

          It’s worse than that. He takes 161w in for 396w out. (You missed his 40w atmospheric “window.” I think Trenberth took these readings at the geyser basin at Yellowstone Nat’l Park.

      • Tel says:

        He has back-radiation four times larger than evaporation. That doesn’t sound plausible.

        To really believe he can calculate all of those numbers accurately enough to get a net absorption as the final difference figure is ridiculous.

  7. PetterT says:

    An insulator around an object will make the object warmer only if the object is heated by a (constant) heat/energy source.
    A house heated by constant electrical energy will be warmer if the insulation is increased (more and better insulation sprayed into the walls). Then you can turn down the electrical heaters and save money.
    A person, heated by the processes in the body, will have the same temperature when putting on more insulating clothes, but will burn less energy.
    A heated stone, taken out of a furnace and wrapped in insulation will not be hotter, but reduction of temperature will be slower.
    The earth is heated by a constant heat source, the sun, and if anything that reduces outgoing radiation from the earth is added to the atmosphere, then the earth will be warmer (house analogy, but we can’t turn down the sun).
    Whether CO2 reduces or increases outgoing radiation is still debated, however only +100 ppm more CO2 in the atmosphere since “pre industrial time” seems to have negligible effect on mean global temperature and even less influence on climate which is made by > 100 factors, many more important than the “greenhouse” effect.

  8. nickreality65 says:

    The insulator doesn’t increase the temperature of the hot object. If – If- If you want to maintain the same heat flow – you – have to turn up the heat. The insulator doesn’t do that by itself.

    • Neal S says:

      I thought insulators worked by interfering with heat flow. An insulator can impede heat flow all by itself. And if you want something hotter, perhaps you do NOT want to maintain the same heat flow, But I guess you just crank up your thermostat in your un-insulated house because after all, you say that insulators don’t increase temperature of hot objects, and you want to maintain the same heat flow.

    • I see, so a blanket can’t warm you up. You deserve a Nobel Prize for that discovery.

  9. richard says:

    I think we can safely assume that if there is limited cooling something will heat up.

    “If an object is emitting heat, placing an insulator around it necessarily has to increase the temperature of the source. In order to dissipate heat as the edge of the insulator warms, the heat source also has to warm.”

    This scenerio from Steve mirror the effects seen in the desert. What happens if we add cooling as seen in the atmosphere. So now add cooling pipes surrounding Steve’s object above. The movement of a cooling fluid will take away the heat.

    All Steve’s analogies, the blanket , the insulator are static .The atmosphere is not static.

  10. Gail Combs says:

    And just to complicate matters even more….
    A Note on the Stefan-Boltzmann Equation by an engineer that Jennifer Marohasy though impotant enough to post at her site.

    After a long analysis the conclusion is “In summary there is nothing settled about the Stefan-Boltzmann equation. It cannot be used on its own to determine atmospheric temperatures.”

    It is getting more exciting than watching a rugby match {:>D

  11. Terry Jay says:

    Warm body with internal source of heat. Insulator does NOT cause warm body temp to rise, the insulator slows the loss of heat. This assumes the surrounding temps are colder than the insulated warm body. Example: Put on a down jacket and hat in a cool building with no noticeable wind. Does the body temperature rise? Now do the same where the temperature of the surrounding air is 110. The insulator retards cooling and the body temp will rise, but never match ambient.

    • So insulating your house doesn’t make it warmer? You deserve a Nobel Prize for that discovery.

      • Mack says:

        Too late Steve…The Nobel Prizes have already been given out to Big Al , and the traindriver Pach….?..whatever his name is.

      • Terry Jay says:

        Uh, try again. House insulation retards heat loss. If you set the thermostat at 70 in an insulated house it will take less energy to reach and maintain that temperature.as compared to a less insulated house.. What insulation does not do is magically make your house 75 when the thermostat is set at 70. You may have a point to make, but the snark factor is hiding that point pretty well.

    • Michael 2 says:

      “Warm body with internal source of heat. Insulator does NOT cause warm body temp to rise, the insulator slows the loss of heat.”

      And by reducing the loss of heat energy, more accumulates on the body, raising its temperature.

      Your subsequent comment is a “trick” that changes the parameters and is not proper argumentation.

      “Now do the same where the temperature of the surrounding air is 110. The insulator retards cooling and the body temp will rise, but never match ambient.”

      Pretty soon the body in the insulated jacket will exceed ambient and you’ll be dead, for the body is generating heat energy that cannot escape, plus the heat energy that works its way through the insulation.

      Wearing a jacket works for *brief* exposure to hot air since it slows convective heat gain from the hot air, but it also stops required heat removal from a human body.

  12. Billyjack says:

    “The insulator does not change the direction of the heat flow, but it does increase the temperature.”

    An insulator reduces the “rate of loss” of heat from a heat source. An insulator does not increase the temperature. If a constant heat source with constant energy input shows no temperature increase in air, then is wrapped with an insulator then the reduction of heat loss will cause a temperature rise, but the temperature increase can only occur due to additional energy input into the source. Said another way, a hot object with no additional energy input will not increase in temperature by being wrapped with an insulator. This entire discussion is reminiscent of Grubering.

  13. Rick Fischer says:

    This is a quibble, in the interest of clarity. If an object is “emitting” heat (assuming you mean “net emitting”), that only means that it is warmer than its surroundings. I think you intend to say, if an object is generating heat energy. Then your examples work. I would go further to say even if an object is generating heat energy, it may be receiving net heat if its surroundings are warmer than the object.

  14. Baa Humbug says:

    If an object is emitting heat, placing an insulator around it necessarily has to increase the temperature of the source.</blockquote
    In order to avoid nit picky responses, perhaps the above should be restated as follows…

    If an object is emitting heat to cooler surroundings, placing an insulator around it necessarily has to increase the temperature of the source.

    The first version isn’t accurate as it does not apply to… say ice cubes… in a styrofoam box.
    In this case, the insulation slows down the warming of the ice (source) which can be taken as cooling, just like slowing down cooling can be taken as warming.
    IMHO

    • Michael 2 says:

      “just like slowing down cooling can be taken as warming.”

      Not to me, warming means the temperature is rising, cooling means the temperature is falling. Just because the temperature is falling a bit less rapidly than some sort of unstated standard does not mean warming.

      But I recognize a parallel in politics — “reducing the deficit”. What actually has been reduced? Nothing; it is still a deficit and the debt is still growing. So if the debt is graphed, the deficit is the first differential and the “reduction of deficit” is second differential when you notice that the rate of the increase in debt is a bit less steep.

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