Imagine that the heat the instrument experienced rising from the earth is mostly transported there by convection rather than radiation. Additionally some conduction through the instrument would occur from that convection. Then any calculation that assumes only radiation heat transfer will greatly overestimate the numbers.
Basically the experience of anyone who has had to do this to compare models to real life, is that radiative heat transfer only dominates when the source is at a very high temperature. For low temperature objects, the secondary convection arising from the radiation is dominant and the direct radiation heating itself is minor. You can test this yourself with a radiator next Winter. The Earth temperature is rather lower than even a radiator so likely there is very little direct radiative heating on the instrument.
But, as I said, the disbelief and argument about numbers would be null and void if they used only the net value which is An enhanced greenhouse would just show a reduced net value.
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What therefore is the point of showing back-radiation? It doesn-t even make any sense that there is no radiation upwards that equally matches the back-radiation, as the theory requires. I just cannot fathom how those upside down Australians manage to hold on. The sun radiates with practically no power below 4um and downwelling atmospheric radiation practically no power above 4um. I just replaced two way numbers with a net number. I already mentioned this before somewhere, but please do not quote only a part of a sentence, otherwise you will missrepresent what is being said.
It is telling that this second time you complain, you have still not managed to display what misrepresentation happened. That there is a NET flux of 66 shows that the second law is not being disobeyed: heat flow is from higher to lower temperatures. On the quoting part — in my opinion there is a profund difference between saying there is no downwards radiation and saying that it can be presented as a reduction in terms of total energy loss of upwards radiation or in other words net balance.
The numbers should still all add up in the Trenberth and Kiehl picture. The idea behind the energy balance diagram is to understand all of the surface fluxes and all of the TOA fluxes. If you replace the up and down flux with a net flux you have removed useful information from the diagram.
To calculate absorption and therefore atmosphere heating you need to consider the absorption of both up and down fluxes through the atmosphere. Not net flux. I would argue that neither does back radiation to be honest. As there are more methods of heat transfer besides radiation, I would say that temperature explains the back radiation not the other way around. I just tried to present a bit of a different view on the same subject, which might be somewhat easier to digest for some people. It should be more — is a ping pong ball falling on earth or earth falling on ping pong ball — kind of a question I would say.
Is there a slight transposition error in the opening paragraph? BTW, as a layperson I think that this site and skepticalscience provide wonderfully complementary resources. Thank you! A fascinating model. Perhaps the equations fail to be valid as you have defined the parameters of the materials? The temp profile must be a continuously decreasing curve as you go out. This is NOT reality. Eli once told me that each absorbtion takes a few nanoseconds, so equilibrium takes at most nanoseconds — ie FAST 2.
10. On Duhem’s Energetics or General Thermodynamics
The K-T diagram is not real. It is an annual average construct. It is missing a term at the bottom that represents the energy provided by the Earth temperature your 30KW lightbulb. At night when the solar insolation in equals zero, but the ground still radiates IR energy out, the GHE still continues albeit at a slightly reduced rate. The question then is where does this energy come from, since solar insolation is actually zero?
AND where is it counted in the K-T diagram? The ground energy is real- conventional wisdom is that it comes from radiaoactive decay. I claim it comes from the forces of gravity impacting the Earth- eg the moon causes tides which cause friction which generates heat. The K-T diagram is missing time dependance.
NOW when the Earth is further away, what happens to the Earths gravitic potential energy? Where does the energy come from? Does it get taken out of the Earths kinetic energy ie temperature? Ah, try opening your mind to the possibility it IS right and that eminent scientists who have studied this for years have it right and you have it wrong.
Go and find out how long it takes to emit 15um from CO2. And how long between collisions is it at STP? Well, yes. This is the time-independent part. Changes over time take things out of balance, therefore putting time dependency in makes it not an energy balance diagram. Nice to see someone make the claim. And by the way, that diagram is simply the latest in a long line years of papers to attempt to calculate the average values for different aspects of how energy moves through the climate system.
Suppose — crazy thought I know — but suppose you are wrong. Just entertain the thought for a few minutes. The temperature at the outer surface is the same as the temperature at the inner surface.
Which one do you want to pick? The only way that the inner surface radiation can match the outer surface radiation is to be at the same temperature. But everyone can see that it will be hotter. The first law of thermodynamics simply states that energy cannot be created or destroyed in a system. No energy is created or destroyed in this system. Therefore, this system does not violate the 1st law of thermodynamics. They are averages. The usefulness of an average can be questioned of course..
The sun heats up the atmosphere. The atmosphere can only radiate lose heat at a certain rate compared with the stored heat. In fact, the explanation is simple. You can measure the temperature of the atmosphere at night. Therefore it will still emit radiation. The global annual average includes the night-time.
No, convectional wisdom is that it comes from the retained heat in the surface of the earth. The earth cools down slowly. However you should still be able to calculate transfered heat from T1 and the temperature difference. From what I understand that is actually the same for conducted heat that you need to know T1 and temperature difference , as conductivity is usually temperature dependendent. Could you explain for your readers the difference between a scalar quantity and a time dependant vector quantity? If you sum the values across the K-T diagram at any level you get zero, ie equilbrium at any particular instance of time.
However if you try to add the outgoing flux to the backscattered flux you get a positive value of In fact the two values are probably using the same photon of energy which gets absorbed and a few nanoseconds later backscattered. Its a steadily declining temp profile. Given that the transmission of the photons is a vector, then adding the multiple backscatters needed to get back to equilibrium which is what your T1 calculation did is NOT mathematically nor physically valid.
The SBL by definition occurs at every point on the way out. Mathematically you can NOT warm the interior by backscatter and add the energy without violating conservation of energy. And you need both energy from outside the system and an impediment to that energy leaving the system. Mark , you missed my point, or I failed to explain enuf. In order to warm you have to add MORE energy than what is already coming in.
Same applies to pipe insulation. When you drive to work, it takes time and in that time an interval of linear distance is traversed. This is a real phenomenon predicated on the simple maths that the average speed can be calculated by taking the total time and dividing by the total distance traveled. That you never went at that speed for any significant time is irrelevant to the supposition of whether your average speed can be calculated. The values are not equilibrium at any particular instance of time. The values are the global annual average for each component.
If they cancel vector wise then you are left with the equilibrium in equals out. This kind of comment is quite confusing. Outgoing flux from the surface is happening continuously, as is incoming radiation from the atmosphere DLR. And then onto my model. You finish up with:. Mathematically you can NOT warm the interior by backscatter and add the energy without violating conservation of energy…. Do you think the temperature of the inside of the sphere is higher than the outside? This is an important question to answer. The outer surface of the sphere will radiate energy out to space, and while the sphere is radiating less energy than it is receiving it will heat up.
The equation governing the temperature difference between inner and outer surfaces is simply application of the 1st law of thermodynamics with the material property of the sphere. If 30,W flows from the inner surface to the outer surface then the temperature difference is easily calculated. The temperature differential will keep increasing until enough heat flows out to balance the heat added to the system.
The equation governing the radiation from the inner surface is simply the Stefan-Boltzmann equation, using the temperature already calculated. Go step by step through the maths and explain where the error is, e. First I really appreciate you guys responding scientifically so please continue. I shall attempt to explain my position. My bottom line is that adding more GHGs to a system without adding more energy or photons will not result in more warming. So yes it is warmer inside than further out. It can not get any warmer than the only source of energy, the 30KW. Your model calculation of temp at T1 being way more than 30KW going out is just not possible.
OR you violated the first law of thermo. I do like the model- it simplified everything down. I think the confusion comes about because of the various diagrams like K-T, and like the simplified halfup- half down type diagram. They mix and match numbers under differing circumstances. Obviously this is NOT equilibrium. This continues for bounces about a microsecond at ground or GHG absorptions, until the half up and half down equals ie equilibrium. Bottom line the half up half down diagram is NOT equilibrium.
It is an instantaneous depiction of the first absorption process that actually takes a few nanoseconds. It is NOT real- we are never at a such a situation as depicted- but it sure explains what is going on. At equilibrium the NET of the time dependant vector energy is up at all points. You do not add the up and the backscatter down unless you apply the up and down signs to get the net number. I think it added the the multiple back radiation values required to get to equilib without using negative values since these are time dependant vectors not scalar numbers.
My answer- the equation while valid for heat transfer is not valid for calculating the temperature???? My bottom line conclusion is that you cant get a higher temp or increased radiation without adding more energy — ie adding CO2 alone can NOT cause extra warming. They are trying to show what happens at equilibrium, ie in and out. So how did it get so hot if we are always at equilibrium and no energy crosses the ground barrier- at least according to K-T?? I also have a problem with the number, or actually the which is plus reflected solar of Even when applying the standard conversion of the Earth diameter area to the half a sphere area that receives the incoming energy.
There is missing energy the subject of a Trenberth paper My theory is that the missing energy is not actually missing, it is in the form of outgoing forces of gravity and magnetic field energy that is not measured by the satelites. I also have a problem with reality. Finally Jupiter has a long term eccentricity of about 50K needs to be pinned down??
I would welcome any comments! Sorry for the length! Now if you input the same amount of energy into each sphere, will they only reach the same T? Obviously not, aluminum damn American spelling is vastly more conductive than steel, the energy will pass through it to the outer shell vastly faster than through steel… so, if the same energy is being input into the spheres, what happens to the extra energy that is input into the steel sphere over the longer time it takes for the energy to reach the outer shell? There will be more energy in the steel sphere….
Im sure you would agree this would mean a cooler surface? So right off, this would obviously mean less conductive losses, even if we ignore radiation… But the same basic principle applies for radiation as for conduction. Some will be in the direction of the earth, so this will offset radiative losses from the ground up….
But this is NOT new energy, created energy… this is just slowing its migration to space. The same as steel will hold more heat than aluminum. I understand Aluminium. They wll get to equilibrium at different rates due to the transmission heat transfer differences and hence different 0. So at equilibrium there WILL be more energy in the steel sphere, true.. BUT if the steel shell gets hotter on the inside edge by retaining heat slower transfer it will then conduct more energy faster and with the lower emissivity to vacuum end up hotter at the surface.
If as you describe the atmosphere is totally transparent no GHE but can use conduction? Then the rate of heat transmission changes faster- since a photon that would have been GHE absorbed will now go straight to space with less delay - conduction is probably changed minimally in getting to the equilibrium surface temp which in the no GHE case will differ lower or cooler ground surface as you said- , not sure about the differential Ts since the TOA temp will also change with the change in no GHE.
I think we are consistent in the results. My key point not addressed in your response unless I misunderstood is that yes you get temp and rate changes during transitions to equilibrium, happens every morning and night or with different materials BUT on Earth at equilibrium, even if man adds more GHGs you do NOT get more absorptions or changes in that GHE warming because without adding photons from outside you can NOT get more GHE warming.
All the photons are already in use causing the equilibrium and maximized GHE, because there are excess GHGs in the air. Arrhenius and IPCC are wrong. Taken in context of the paragraph, i wasnt talking about the spheres, but surface interactions of a planet with an atmosphere. But maybe i was just confusing the issue by bringing conduction into it….
But i shall just get this straight, you acknowledge that the properties of a material, will effect its energy carrying capacity? And you understand how the GHE increases the T of the surface of the planet, by increasing the energy contained in the system? But you believe the amount of energy contained in a system cant change? So i have a aluminum sphere, we input energy into it, till it reaches equilibrium, then we encase the aluminum sphere with a steel sphere, now by your own reasoning and mine this will mean more energy is contained in the system… but from your reasoning, this would mean that this extra energy dosnt effect the system?
It cant just disappear. Energy in will still always equal energy out, but the amount of energy contained in a system matters. The Stefan-Boltzmann law tells you the thermal radiation from a surface. Within the PVC sphere the only net heat will be due to conduction. Conduction only occurs when there is a temperature differential. Follow the equations. They are correct. And see Part Two.
By the way, the key is that in the case of the sphere, the net radiation at the inner surface is only 30, W. SoD That ebex experiment was new to me. Of course i was referring to all the other radiation measurement instruments that purport to observe things that are actually achieved by calculation. I cannot get my hands on tech details of ebex but it seems they are measuring heat fluxes rather than radiation. If they are measuring radiation rather than assuming it then I withdraw my objection though I still find the numbers strange and I still see no need to split out back radiation from the net value in the first place.
I do know that you cannot separate out radiation and convection in 1D calcs and hope to get the right answer. You need an iterative 3D radiative-convective model for that because there are just too many interactions and potentially false assumptions. So forgive me if I am a bit dismissive of these simplified hand calcs that never have to be checked against the real world.
Mark Try not getting confused yourself before you accuse others of it. The equal up and down radiation refers to the atmosphere radiating in all directions. Hence the cartoon is misleading from the outset. As I said though there is no need for separating out up from down radiation because nothing depends on it. You can happily use the net value.
On reading one of Craig Bohrens books I noticed he said some physicists prefer to talk about net and others prefer to talk about back radiation. Nobody needs to be castigated for not accepting one definition over another. IOW There is no need for a love-in with back radiation. Lastly why would I not believe that generations of scientists have ignored convection in favour of radiation in their atmospheric calcs, when that is exactly what they did with a real greenhouse from which the name greenhouse effect comes?
Secondly the textbooks have wrongly ascribed aerofoil lift to the Bernoulli effect for nearly as long. Yes generations of scientists making the same assumtions and making few backup experiments can indeed be wrong en masse. As I keep repeating though, the net effect is the important one. Nasa believes it too. Its easy to be a smart ass but really clever people tend to like to admit to the huge amount we still have to discover before mentioning the remainder that they think they know.
Even more clever people have studied scince history and found that the majority have very often been incorrect and always defend the point of view they have spend 30 teaching to others. The single biggest mistake we make is to assume x is not important therefore we can concentrate on y. One day you might learn that. Not co existing with matter! Well the problem with dark matter and thus dark energy is that it dosnt interact with matter… the only way thus far found to measure it is through gravitational lensing, its interaction with gravity, the way it warps time and space, and this warps effect on light.
Have you ever wondered why a piece of iron that is heated up around the k mark glows red? I can see with my eyes the short wave radiation from the sun, and feel its effect on my skin. Buffoon was right. If you actually had 1. So you could not only tap the original 30,, outside the sphere, you could tap that 1. If you used that 1. Your entire exposition is ignorant fantasy. Regardless of the amount of heat being conducted the emission of thermal radiation from a surface follows the same formula. This example has an emissivity of 0. A blackbody has an emissivity of 1.
If we move to the climate system.. The reason can be easily found by applying basic heat transfer equations. Well, to prove the example wrong needs a demonstration of which equation is incorrectly applied, or where the maths is wrong. Each square meter of inner surface is receiving So how can this inner surface reach a vaporization temperature?
We have found the equilibrium, so therefore the system is nicely in balance. Equilibrium is found when enough temperature difference exists between the inner and outer surface to conduct away the heat from the energy source. Conduction requires a temperature differential to drive heat. At this temperature difference each part of the inner surface becomes quite hot and is therefore radiating substantially. If the inner surface is, therefore, at a higher temperature how much radiation does each square meter radiate and how much radiation does each square meter receive?
In the real world, your hollow sphere would come to thermodynamic equilibrium, the inner surface would have the same temperature as the outer, and it would be in equilibrium with the radiation from the source, and is THEN emitting as a blackbody, just like the outer surface, a total 30, watts, which is cancelled by the 30, from the source. The whole world of science is incompetent. Believe it or not. Well done for thinking of it, F for throwing it away. I suggest—strongly, and as a professional scientist—that you shut it down for a while, get in touch with everyone linking to this web site as something to follow for good science, and consider very seriously what I said about the general level of competence in science.
In the real world, your hollow sphere would come to thermodynamic equilibrium, the inner surface would have the same temperature as the outer.. If the inner surface is at the same temperature as the outer surface then no heat will be conducted from the inner surface to the outer surface. This means that the energy source of 30,W has no way of leaving the inner surface — because the only heat transfer mechanism to reach the outer surface is conduction. As a result, in the scenario you paint, there would be an accumulation of energy but no change in temperature.
This would be a violation of the first law of thermodynamics.
This 30,W is being radiated from the inner surface. Please explain how energy is moved from the inner surface to the outer surface if there is no temperature differential. What is the mechanism:. Many surfaces do not radiate like a blackbody, and the example in this article is stipulated to radiate with an emissivity of 0. Probably the concept intended is to radiate according to the Stefan-Boltzmann equation, which is blackbody radiation x emissivity. If you can prove that heat flows through a material when the inner and outer surfaces are at the same temperature you will be on that coveted plane to Stockholm to pick up your Nobel prize.
Everyone will know your name. You will find that the equation of conducted heat requires a temperature differential:. See the comment above for more explanation, written before I pulled your last comment out of the moderation queue. It picks up childish insults. The maths is at the end and takes up a few lines.
The issue is the temperature mean and profile for externally heated planets. I contend the only way for Venus to exhibit a surface temperature more than twice that of a gray sphere in its orbit is to have an internal source of heat. Perhaps you are agreeing with me? Solar radiation is centered around 0.
This means that a planet can have an absorptance for solar radiation that is totally different for its emittance for terrestrial radiation. This is the case with earth. You still did not address in what way your example with an internal heat source is relevant to the externally heated balls. Ah , peer review! The Stefan-Boltzmann law says energy density is proportional to the 4th power of temperature. Virtually all our energy comes from the sun. It subtends about 5. Thus 5. The commonly claimed kelvin computation is in fact a little beyond what is possible for even the most extreme spectrum which displays our approximately 0.
I DARN well know how to calculate the temperature for any multi-colored multi-spectral ball heated by sources of any spectra. If your point is something different from the earlier discussion , then have another go. We measure this reflected solar radiation by satellite. We measure incident solar radiation by satellite. There is no confusion about these numbers. Since the computation is temperature to temperature , the Stefan-Boltzmann constant drops out. Multiplying the total energy from the sun 5. Your absorptivity value of 0.
The claim , which gets sloppy is that the spectrum of the earth without an atmosphere is so infra red that the correlation with all of the sky other than the sun is approximately 1. The essential point is that the unbiased hypothesis is that of a flat spectrum gray ball. We know this because we measure the reflected portion. Given any particular spectrum , the equilibrium temperature is a rather straight forward calculation. There is no requirement for the absorptivity of a body at 0.
Snow and ice for example are highly reflective for shortwave solar radiation, and yet are highly absorbing for longwave terrestrial radiation. This is very basic and has been explained to you a few times already. Surely some student interested in the field has the time , which I do not , to actually find and confirm the relevant broad band spectra , and present actual equilibrium temperatures for substances of interest.
Your question does not make sense. This is why I keep pounding at the pathetic state of the understanding of this very most basic physics. And please, read this and study it before sounding off in your usual manner about what an idiot everyone else is. Absorptivity is a function of wavelength and direction 2. Emissivity is a function of wavelength and direction 3. Solar radiation is emitted in a totally different range of wavelengths than terrestrial radiation.
There is an alternative explanation. Bottom line , you do not know how to calculate the temperature of a radiantly heated colored ball. I do , and am working to make the executable algorithms more and more understandable on my website. The fluxes have opposite direction, therefore sign, and cancel out. A little warm IMHO.
I was glad to see this article use a nominal emissivity of 0. There's plenty of evidence for supposing that the earth's emissivity is similar. It most certainly can't be a perfect black body with emissivity 1. If that were so, radiation physicists wouldn't need to struggle to create reliable black body reference sources for their experiments — all they'd need would be a handful of dirt or a bucket of sea water.
He used 30, watts for the value qr when qr is actually the watts tranfered by conduction watts. He then came up with a temperature difference of K when it is actually On the Hockey Schtick we have a system with 30,W input and 24, output. It seems that 19, watts magically appears at the outer surface — it can only get there by conduction from the inner surface. The example you are showing, of a sphere Earth whose inner core is radiating And of course atmospheric gases at lower temperatures and at lower pressures cannot raise the temperatures of Earth surface where you can find higher temperatures, and higher pressures.
Even if you to Termosphere, which is highest point of terrestrial atmosphere between 80 — km. If the atmosphere did not interact with the radiation then you would expect the top of atmosphere upward radiation to be the same as the surface upward radiation. The atmosphere does interact and you need to solve the radiative transfer equations to calculate the change in radiation. Read Theory and Experiment — Atmospheric Radiation. That should be enough for now. Feel free to post your questions about those articles in the comments there.
I imagined that almost no one would have a problem with the model created. Instead, I thought […]. Moreover, it is not true that higher pressure do not cause higher temperatures, and regarding Venus, you disregarded both the 92 bars at surface, but above all the fact that — as prof. On the contrary, true data show that gravitation, atmospheric pressure, convective heat transmission, are the main factors to explain heat trasmission, while radiative forcing and Boltzmann equations are clearly rough and misleading for this purpose.
We are about 10c warmer that a gray ball in our orbit. In the standard science I was taught, gases had weight and separated out unless work was done to change this. This point was conceded to me. I suggested a scenario to make sure we fully understood what the other was saying. Take a room, Carbon Dioxide is introduced in a large enough quantity for it pool on the floor. Nothing changes in the conditions of the room from what it was which allowed the carbon dioxide to pool, i. I said it would stay where it was. He said it would diffuse into the atmosphere and become thoroughly mixed and it would take work to unmix it.
I said his idea was impossible because carbon dioxide was heavier than air, 1. He said that molecules travel at great speeds knocking into each other and so thoroughly mix up together. He pointed me to gas laws to prove that this was the behaviour of gas molecules so I was wrong. I began researching gas laws. And discovered that these referred to ideal gases, not real. It is useful in some calculations just as the imaginary average is useful.
To find how a real gas acted in the real world, stages would have to be gone through from the initial gas law to arrive at an approximation for a real gas. The ideal gas laws do not describe real gases, in the real world. They do not have volume, not subject to gravity and so on, to use them to describe how CO2 would act in the real world is actually non-sensical, but because of AGWScience this is firmly believed to be true. Recently I saw a research paper from AGWScience which set out to prove that methane separated out at the ceiling of a mine would thoroughly mix back into the atmosphere of the mine.
The AGWScientist concluded that there must have been an undiscovered source of methane entering the test mine which was causing the methane to continue pooling at the ceiling. The reality in RealScience is that methane separates out because it is lighter than air and so will form a layer at the ceiling of a mine.
Miners know this well, they used to, perhaps still do in countries where mining is not well equipped, cover themselves in wet towels and enter new mines with a lit candle on a long pole to set fire to any methane there before mining could begin. It is so much simpler to accept standard, well known, observed, tried and tested, real science, than propose answers when to explain an imaginary hypothesis when observation fails to confirm it.
Air is a medium. Our atmosphere is not a vacuum. Our atmosphere is like an ocean of air above us and is subject to gravity and pressure and the molecules comprising it have volume, react with each other — they do not travel at huge speeds in empty space bouncing off each other. Real gas molecules move in a real medium, air, not empty space.
The ideal gas is not real, it does not describe a real gas molecule in the real world because it does not behave as a real gas. Carbon dioxide is 1. The key word here is displacing. A description from RealScience. Neither does carbon dioxide move in a mixture of molecules to pool on the ground bringing this mixture down with it.. And so the problem here with the laws of thermodynamics. When something is a law it is not a hypothesis, nor even a theory, try fitting the parameters into the laws first. They include sensible and latent heat convection. Conduction is only important at the surface of the earth as part of the convective heat exchange as the atmosphere has an extremely low conductance.
Do these rooms where CO2 pools have wind or convection currents? Wind can actually do work and mix gases. Air samplings at various altitudes have confirmed this. We see the same sort of thing with the creation of clouds. The condensation nuclei for the water droplets are very tiny pieces of dust, salt, etc. These are even more weighty than CO2, but they get up there. Of course, you already know this answer if you actually read answers to your previous questions. No, the set up of conditions for CO2 pooling in the room was that there were no windows open or fan on, no movement of air.
So I said that without a window being opened or fan put on the CO2 would stay pooled, he said it would diffuse into the atmosphere without any work being done, such as no window opened or fan put on. An interesting aspect here, in my previous discussions about the CO2, was that other examples of its properties were also dismissed and slightly tweaked as with the weight to conform to AGWScience, tweaked enough to make it seem plausible. I was given examples using dry ice to show that it diffused into the atmosphere at room temperature, that CO2 is invisible had to be ignored, it took a while to discover they were mistaking water vapour for CO2 , and I was given a long explanation of how it was toxic to the body, regardless that it has long been designated as non-toxic in RealScience!
There was one such on the BBC a while ago. The understanding of experimentally confirmed macroscopic physics has declined sadly since my school days. Various people have tried to explain the absolute basics to Bob, including me in — this explanation. I suggest anyone who wants an introduction , with actual computations , to the problem browse my website.
I had assumed it had been done in confirmation of those ideas in the early 20th century. A surface with an emissivity of 0. Actually it is You should be clear that if you use pi to only 3 significant figures you will not get an answer for area which is accurate to 6 significant figures. And so — back to my comment of March 21, at pm — redo your calculation of temperature with this flux value and you will see that my original number is correct. Or we can just write it as m 2 for now. This is an engineering problem requiring a heat transfer solution not a radiative physics problem.
I will paste in a few textbook samples by way of illustration, no doubt in vain. Why would textbooks on heat transfer be more valuable than the blogs you have come to believe in? However if you put a heater inside the thermos the coffee gets hotter. Because the input of heat exceeds the output. However it is the heater that heats the coffee not the outside of the thermos. You falsely assumed that the outside of the sphere radiates energy towards the inside. This is totally impossible because the only heat source is the internal radiator.
Heat transfer is unidirectional from the inside surface of the sphere to the outside along a thermal gradient. The external surface only radiates to space which has zero temperature. Because a vacuum is devoid of mass and energy. The radiation simply pases through without heating. First you claimed — March 21, at pm — that I had incorrectly calculated the outer surface temperature, T 2 , of the outer surface.
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You said — without proof or even citing a formula — that the temperature, T 2 was 10K not K. I provided the calculation and so second — March 22, at am — you switched to claiming arithmetic errors on my part. I got the correct answer because I used the correct value of pi. Why are you using the Stefan-Boltzmann Law? A black body is an idealised cavity radiator of zero thickness surrounded by a perfect vacuum. I explained, with reference to heat transfer textbooks, that the Stefan-Boltzmann law is not about black bodies.
The Stefan-Boltzmann law is about emission of thermal radiation from all bodies. So now, fourth , you switch again and start making all kinds of inaccurate claims. For example:. Instead of ranting you should be interested to find that you are plain wrong about the Stefan-Boltzmann law. You should be interested to find out that the Stefan-Boltzmann law is not just about the ideal case of blackbodies. You should be interested to find out that heat transfer textbooks use it as the only equation for emission of thermal radiation. You incorrectly assume that there are two separate Black Bodies on the inner and outer surfaces of the sphere.
In this case the radiative flux and temperature are identical on both the inner and outer surfaces of the film. However your model as depicted is simply that of a heat source contained in an insulator — literally a light bulb in a box. This is a thermal conductivity problem rather than a radiative physics problem.
The correct method for calculating that is to use the heat equation — not the Stefan-Boltzmann Equation. It uses the Stefan-Boltzmann formula which is the only equation which describes emission of thermal radiation and is not an equation only for blackbodies. So if you want to discuss a subject instead of ranting — explain which formula you will use for emission of thermal radiation from the outer surface of the sphere.
Is my arithmetic wrong for the surface area of the sphere — or, is yours wrong? You were the one who wanted to make an issue out of it. A temperature can be assigned to a point in a vacuum simply by adding up all the energy impinging on it from all directions. That will give the temperature of any gray , flat spectrum , ball at that point. As I posted way back , the issue with the example is its relevance.
The issue is the temperature of spheres radiantly heated from the outside , not the temperature distribution of internally heated spheres. You do seem to bring them out of the woodwork! Your heat transfer model is brilliant, a wonderfully counterintuitive way of leading fools into making absurd statements.
It a very clever example, and I congratulate you for designing it. The mathematics are clear and unequivocal, yet so many have trouble understanding the implications for climate and weather science. I wonder if part of the problem people have understanding the Trenberth and Kiehl diagram is that only the ground radiates like a black body.
This is a consequence of the Schwarzschild equation. Of course a hollow sphere heated up from inside will have a higher internal temperature than external. Everyone knows that. Of course the radiation away from the outer surface must match the energy being supplied inside. Almost everyone knows that. The author has created a hypothetical perpetual motion machine consisting of a light bulb in an styrofoam box that is magically heated by back-radiation. Like Arrhenius he has created a hypothetical PVC aether with magical properties that defy the rules of electromagnetism to obtain his answer.
By definition a black body is a unidirectional outwards cavity radiator of zero thickness. If we assume that the inner surface of the sphere is a real black body then the radiation is only inwards towards the radiator. So the PVC is not heated at all and remains at absolute zero. Therefore no inward energy flow is possible from the PVC sphere even if the radiator is turned off.
From real world experience we know that cooling of an insulated box will progressively occur from the radiator to the outer surface.
Therefore the temperature must always be: T. If the source of energy is turned off, the PVC sphere will cool back down to 0K actually to 2. A body with an emissivity of 0. This is taught in all heat transfer textbooks as already explained — and shown from scanned textbooks. So please, explain what the surface temperature of the outer sphere is, for a body with an emissivity of 0. If I now take your most recent comments you claim that the outward flux from the sphere into space is zero? Previously you stated that the outward flux into space was So why not explain, with reference to heat transfer textbooks, what the outer surface temperature, T 2 is?
What is the surface temperature of a body with an emissivity of 0. With a reference for your temperature calculation. What is the surface area of a sphere with a radius of 13m.
Is it Or is it A calculated temperature of k for the outer surface is incorrect because have used a method that is only applicable for a two-dimensional surface. You need to use equations applicable to a solid-state such as the Debye Model or the Einstein Solid Equations. An internally heated sphere emits radiation at all levels not just at the surface. Because the sphere has a variable internal heat distribution it will emit radiation at a continuum of wavelengths according to a Gaussian Distribution.
An observer outside the sphere equipped with a wide-spectrum radiometer would measure the mean temperature of the sphere not the surface temperature. A real world experiment using thermometers would probably show that calculated values are way out anyway. If anyone has a few million bucks to waste they can try this experiment at home. This is what it will look like:. When you have completed this calculation you will understand why all heat transfer textbooks show the emission of thermal radiation from solid surfaces as a dependency on the surface temperature and the emissivity of the surface — and not with a dependency on the temperature profile below the surface.
All calculations have been double-checked by back-calculation to obtain the original 30KW of energy input. I back checked this by feeding the numbers into the following online calculator. A temperature of I should add that this is the correct way, as I have explained to various people, most recently, bananabender. So — either the equation of heat conduction is wrong OR some mysterious new heat transfer mechanism exists OR — the real answer.. The real answer, the inevitable answer, the temperature of the inner surface keeps rising until 30, W can flow by conduction to the outer surface.
Once you have grasped this essential point you see that everyone claiming the inner surface is NOT K above the outer surface is confused about the first law of thermodynamics. Or confused about the equation of heat conduction. Or does the temperature difference between the inner and outer surface have to be K to conduct 30,W through the PVC?
I suggest you: a discuss this problem with a mechanical or chemical engineer who has practical experience. However a light bulb surface is not a black body. The Moon is 60K hotter at night than predicted by theory due to stored heat in the upper surface rocks. This is because the entire 7, tonnes of PVC acts as a heat sink.
When you put a light bulb inside a styrofoam box the inside surface temperature stabilises within a fraction of a second. The surfaces always remain much cooler than the surface of the light bulb. This can be confirmed by touching the inside of the box. What does a blackbody have to do with this? The emissivity of this surface is 0. What is the point of your engine example?
Metals have a very high thermal heat conductivity, so therefore, a very low temperature difference can cause conduction of a large amount of heat. The exact same principle means that as thermal conductivity reduces , the temperature difference required to conduct the same amount of heat increases. Reaching thermal equilibrium in this example — PVC — takes a very long time. You can see in Part Two that it takes many years.
People who do practical heat transfer use these equations. Or use 3d thermal modeling programs that use these equations. So, once again, what is the temperature differential between the inner and outer surface that will cause 30,W to be conducted? Are you claiming the textbooks are wrong? Because that would be embarrassing. Are you claiming the answer can be calculated differently? Because that would be even more embarrassing. You are applying equations intended for a hypothetical two-dimensional static model to a real world three-dimensional dynamic model.
Your calculations are for a sphere that only emits radiation at the inner and outer surfaces and has a substantial temperature gradient exists across the sphere. This also creates a relatively uniform internal heat distribution. Not in the real world. This is because the heat transfer rate is negligible otherwise. Concrete has very poor conductivity. However the heat distribution within the walls of a large building is uniform except at the interfaces with the atmosphere. The only real case where heat distribution is highly non-uniform is when a huge temperature gradient exists across an effective insulator eg applying a blowtorch to the back of an asbestos tile.
In the case of sphere the radiation occurs simultaneously from all regions of the sphere above absolute zero. In practice the time is infinite because each of the the last micro-degrees takes billions of years. Unless the the energy input per unit mass is extremely high there is no possibility of equilibrium ever being approached. The sphere radiates energy proportional to the 4th power of the temperature above absolute zero. So the rate of heating is inversely proportional to the 4th power of temperature.
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Your model has 30x the energy input of the kettle. These equations are useful approximations for designing objects like heat exchangers or tube boilers which are essentially two-dimensional surfaces. Engineers also rely very heavily on practical experience and measured results rather than just using calculations. NASA actually measured the surface temperature of the Moon in the mid s rather than relying on theoretical calculations. This is because the engineers refused to risk the lives of astronauts based on dubious theoretical physics.
In this case the measured temperature discrepancy was up to 60K. The equations are grossly simplistic descriptions of reality and are only correct for certain hypothetical situations. Please provide these numbers to demonstrate you have any idea what you are talking about.
If you calculate them you will find exactly why the textbook cited earlier explains that radiation from a surface takes place from the top micron. OR — Alternatively, provide an equation for the emission of thermal radiation from the outer surface of this sphere. While waiting for you to produce your evidence for the emission of thermal radiation from within a solid PVC sphere, I thought I should comment on this statement of yours:.
They appear in all practical heat transfer textbooks. These are the textbooks used to teach engineers how to calculate heat transfer. It is an equation for practical bodies. Or from experimental results. It is another wild blog claim, last seen in a non-published paper with a picture of a purple balloon as its best feature. If the Stefan-Boltzmann equation is wrong and inapplicable to the emission of thermal radiation from a body, demonstrate it with:.
The heat exchange equations totally ignore quantum surface effects to simplify calculations. The calculations simply assume T1-T2 and are not concerned with how the energy is transferred across a junction. The only reason your model gets the wacky feedback results is because of interface effects. However if you think you can get 60x as much energy out of a system as you put in you should try and patent it. A probabilistic distribution of heat occurs at any point within a system according to quantum mechanical-statistical principles. That is why heated bodies radiate over a range of temperatures rather than emitting monochromatic light.
I worked as a scientist in the food and beverage processing industry for many years so i have plenty of practical experience with heat exchangers, cookers, refrigeration and many other aspects of heat exchange. You assume that engineers spend huge amounts of time using the infallible thermal transfer equations to design an optimum system. Nothing of the sort happens. Engineers typically work with completely standardised components such as pumps, heat exchangers and pipes. They tend to solve problems based on years of practical experience and some estimates.
Therefore, scientists agree that there is no other natural source of explanation for this rapid increase in CO 2 levels than human activity. And it is not a surprise to jump to that conclusion when you take a look at CO 2 emissions data from several countries. Watching the time evolution of carbon emissions from to leaves no doubt that we are the cause of climate change. Global Temperature Rise. Source: NASA. The first, and one of the most dramatic consequences, are rising water levels. All of that melted ice goes to the ocean and is now attributed to sea level rise in the US and all over the world, even reaching distant locations like Indonesia, China, and Japan.
In order to better understand the impact of climate change on sea level rise and therefore floods in coastal regions across the US you can watch this amazing report from CNN that explains this further. Moreover, other consequences of climate change are related to longer and harder droughts across the world, which also leads to less productive and less nutritious crops. Destruction of the ozone layer is also a secondary consequence of climate change. As heat concentrates further in the atmosphere, the contrary process occurs in the stratosphere. As the stratosphere cools down, and the atmosphere heats up, there is a warming-cooling dynamic effect that causes ozone loss.
Due to this ozone loss, the ozone layer depletes and leaves the ground wide open for ultraviolet radiation to reach our atmosphere. This can easily be seen in the ozone hole in the South Pole. The Ozone Hole. Heat waves are also a direct consequence of climate change. They mean more frequent wildfires, longer droughts, and deaths. Source: Center for Climate and Energy Solutions. Stronger hurricanes, storms, snowfalls, hailstorms, and sandstorms can also be attributed to consequences of climate change that will intensify due to radical temperature changes. These consequences and others may not last centuries to become real, but some may only take a few years.
Do Trenberth and Kiehl understand the First Law of Thermodynamics?
Here you can take a look at the contributions from these sources over time. Energy supply sector GHG emissions by subsectors. Source: IPCC. To reduce the effect of this sector on carbon emissions, it is necessary to lower the energy intensity by enhancing vehicle and engine performance and substituting oil-based products by natural gas, bio-methane, biofuels or hydrogen. S Global Change Research Program, released in November , has announced an alarming top date to make a significant impact on carbon dioxide reductions.
A range between 1. The report addresses remarkable impacts that have already been seen in American ground related to wildfires Northwest , droughts North and Southwest , hurricanes South , floods South East , water and transportation failures due to heavy snow, heat waves, and soil erosion Midwest. Based on these results, the US report focuses on the imminent need to reduce the amount and speed of future climate changes by reducing GHG, replacing CO 2, and emitting fossil fuel energy sources with zero-emission technologies such as geothermal, wind, biofuels, hydro and solar.
As one of the most commonly available, accessible, and feasible renewable energy options, solar panels are one of the main drivers in the reduction of carbon emissions across the globe. We can estimate the reductions in carbon emissions by using solar panels thanks to the IRENA calculator. The latest data available on the tool is from and still we have an idea of the great contributions of solar energy into the market. Experiences in the US have shown that around Germany was the greatest contributor in that year with 29 MT avoided and over 35, GWh produced.
This can be translated into 18 million tonnes from coal sources, 3. As solar energy keeps growing every year, these numbers have already surpassed the estimated values. As a reference, nearly GW of installed capacity were available in , but in around GW of installed capacity are available worldwide. One of the best ways that most of us can contribute to the fight against climate change is for more people to hire solar companies to install solar panels on their homes. Solar energy presents a set of advantages that can be used to offset carbon emissions and investing in solar for your house will also help your wallet.
Using solar lights and other solar powered home products all help towards reducing our carbon emissions. The main drawback from using fossil fuels as a source of energy is that to generate electricity, we need to burn them, which leads to high carbon dioxide emissions that contaminate our planet and accelerate climate change. You can see below, the amount of CO 2 produced when a fuel is burned as a function of the carbon content.
Pounds of CO 2 emitted per million British thermal units of energy. Source: Energy Information Administration. On the contrary, one of the intrinsic advantages of solar panels is that they are a sustainable and clean source of electricity production, therefore they emit zero CO 2 because the process to generate electricity is done at the molecular level without the need to burn any component with carbon. Fossil fuels are sources of energy that exist because of decomposed plant or animal matter at high-pressure levels that accumulate underground over thousands of years.
Since planet Earth has millions of years of existence, you can imagine the amounts of accumulated matter. However, despite their abundance, they are still exhaustible sources of energy. In other words, once we extract them all, there will be no more electricity. And it takes millions of years to accumulate the amount of fossil fuels that we will consume in years.
The Global fossil fuel reserves left are estimated to be years for coal, 53 years for natural gas and 50 years for oil. When you compare that, with the 1 billion years of clean available solar energy that we still have ahead of us, sounds like there is no sense to keep pushing on limited sources of energy that will be over in only a century. Since solar energy is inexhaustible, there is no need to replace it with another resource in the future, assuring a safe and clean source of energy for the centuries to come. Fossil fuel electricity consists in burning large amounts of carbon sources to generate the energy that the power grid demands through a thermodynamic process.
However, it is necessary to keep a constant cycle of extraction of the fossil source. People generally focus on the carbon emissions from these sources at the moment of electricity generation, but they seem to forget one thing, the effects during the extraction process. When mining activities are done, exposed rocks are left behind containing the Sulphur-bearing mineral pyrite.
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