There is a new post on the Roy Spencer's description of the "Greenhouse Effect" at The World as Computation.
The comments show again how widely spread is the idea of "backradiation" although it is nowhere described in physics literature, not even on Wikipedia. Notable is also the complete absence of physicists in the debate, leaving room for all sorts of free inventions such as IR-photons busy traveling around the universe carrying little units of heat energy which they deliver to everybody without asking anything, in particular not about the temperature of the recipient.
But radiative heat transfer is a collective phenomenon of resonance between bodies in radiative contact, where the resonance is only causing heating in bodies with low temperature as an expression of the 2nd law as proved in Mathematical Physics of Blackbody Radiation.
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I have commented on Spencer's site, and posted on my own blog:
SvaraRaderaIncompetent Skeptics III: Roy Spencer
I am disgusted with all climate scientists, who have caused the failure of their science.
Claes, man frågar efter dig:
SvaraRaderahttp://www.theclimatescam.se/2012/02/23/ryssvarmen-under-nadens-ar-2010/#comment-270888
Hi Claes,
SvaraRaderaPlease allow me to give you an expanded explanation to your question: Why Is Roy Spencer believing in Back Radiation?
Let’s look at the events leading up the Yes, Virginia post, and him making up his mind that he has discovered ’back radiation’ the climate scientists equivalent of the alchemist ‘lodestone’ turning lead into gold.
A short time before this post Roy bought an IR temperature reading instrument. He posted how overjoyed and happy he was with this new kit. He went outside, pointed the instrument at the night skies and measured the heat radiated from the cold dark skies, the back-radiation that climate change scientists put in their models. A blogger told him that he was not measuring the night skies but the temperature of the dense air layer above his house, but he ignored that. His couple of hundred dollars worth of kit manufactured in the China, can do things better that million dollar satellites!
He then wandered indoors, and pointed his instruments at various things in his house. (Notice how of late he measured the inside of his fridge and freezer; the cat must be fed-up by now.) He sat down, and pointed the instrument at his electric bar heater. He recorded a temperature of 200˚C when the instrument was pointed directly on the heating bar; interesting so far. He then moved a cold piece of metal, he described it as a metal bar, in front of the electric bar heater and then recorded the temperature of the heating bar at 250˚C. So there you are; he proved back radiation. The cold steel bar was radiating heat back at the heating element and the temperature of the heating bar increased by 50˚C.
An Eureka moment of pure joy, a scientific breakthrough, his name will be passed down from generation to generation as the man that showed the whole world how back radiation can be demonstrated!
When I read his blog I was surprised that a supposedly clever man of science can be so naive!
I can remember the old fashioned heating bars that had exposed wires wound around a ceramic rod. When the heater is turned on the whole wire starts to glow, first in the centre, then spreading out towards the ends, until the whole wire is a red, almost yellow, colour, and the heat radiation from the coil spreads through-out the room. Those open wire electric bar heaters are not sold anymore as they are just too dangerous. It is too easy to start a fire if clothing is hung up to dry in front of it.
The modern version of the electric bar heater has the heating coil covered by a ceramic, almost glass like cylinder. The heating wires are shielded from the users by this outer cover. The outer temperature of this bar heater is controlled by two factors: the amount of heat generated by the inner heating element, and the rate at which the ceramic cover can get rid of the heat. Put the heater in a big hall, or outdoors, with some wind blowing or a draft, and the ceramic outer cylinder will dissipate heat so quickly that it will not be as bright, a sign of how hot it is, as when left inside in a smaller room.
Hi Claes,
SvaraRaderaMy conclusion FYI: -
What we have to understand is that the inner core of the electric heater is heated up to about 800˚C, which is the temperature at which steel wire gives off a bright cherry red colour. The heating element is not pure steel but an alloy that has specially been developed and selected to cope with the high temperature and it will have characteristics like higher melting point and lower thermal expansion coefficient to reduce the amount of sagging.
Obviously, the heat of the heater is caused by the resistance of the heating element to the electric current flowing through it. The electric current is supplied by connecting the heater to the mains of the house. The amount of heat generated is determined by the electric resistance coefficient of the heating wire, the current or Amperage, the Voltage at which the current is applied, and the duration the system is kept switched on.
By placing the steel bar in front of the heating element the cooling characteristics of the whole system is changed. Air, which has a far greater thermal transmission coefficient than steel, is being replaced and the ability of the outer ceramic cover of the heating bar to dissipate the heat that is generated from its internal core is lost, and the result is that it heats up. What we have the now is the beginnings of the construction of an oven, Virginia.
Replace the metal bar with a brick that has an even lower thermal transmission coefficient than metal and you have the beginnings of a furnace, and your back radiation theory goes to pot!
An electrical/heating and ventilation engineer will be able to explain to Roy why he measured what he observed, and also explain that blocking a heater is bad practice as you will eventually blow the thing up!
Det frågas efter dig på TCS igen Claes.
SvaraRaderaClearly, Dr Spencer has little knowledge of the engineering subjects of heat and mass transfer nor has he any practical experience with design, measurement and control of furnaces, boilers or heat exchangers.
SvaraRaderaHe says "you can increase the temperature in one of two ways (1) increase the rate of energy gain or (2) decrease the rate of energy loss." He is wrong about point (2). In a furnace fired by a fuel (coal, oil or gas) the maximum flame temperature that can be reached depends on the specific energy of the fuel and the air to fuel ratio. In an insulated furnace (eg in front of a rotary dryer) the flame is about equal to the exhaust gases (for a dryer this is held down to a maximum of about 850C by excess air so that feed chute is not burnt away). With preheated air I have measured flame temperatures in excess of 3000C with heat being absorbed by product. Higher flame temperatures can be achieved by oxygen enrichment. The heat transfer from flame to product in a furnace or "water walls" in a boiler is greatly influenced by the flame emissivity. Gas flames have much lower emissivity (as low as 0.45 for a nozzle-mix burner)than coal (emissivity close to 1)and this results in higher exhaust temperatures and lower efficiency. Gas fired boilers need more capital spent on economisers. Certainly, a large amount of heat transfer from a flame does reduce flame temperatures but this is proportionally less than the change in the exhaust temperature. The aim in most burner designs is to have the shortest and most intense flame with the lowest possible exhaust temperature.
There is no back radiation but there is convection and internal recirculation of burnt and partially burnt combustion products.
cementafriend
As far as I have been able to find, no climate scientist agrees on what exactly they think the physical mechanism of the "greenhouse effect" is. Whether it be: A. backradiation; B. radiative "insulation", C. something else.
SvaraRaderaIt is a farce.
Yes, it is. But Spencer and Lindzen say that there must be something which can be called the "greenhouse effect". This is difficult to refute since it is never specified what this effect is.
SvaraRaderaHaving thus once and for all declared that "there is a greenhouse effect", they continue to say that
whatever it is, it is small, so small that one can say that "there is not really any greenhouse effect". In this way they reach the favorable position of being right while everybody else is wrong, including me.
The Roy Spencer China Syndrome
SvaraRaderaIf the 160 F heat source bar heated with X Watts could absorb B-Watts "Spencer back radiation" from the colder 100 F receiver bar and convert that into additional heat then the source bar would later have to emit X+B Watts. This in turn would have to raise the 100 F receiver temperature. Having done so the now hotter > 100 F receiver`s "back-radiation" would also increase to B+b1 Watts....and must according to Spencer raise the temperature of the source bar (again)...Of course Spencer does not explain what happens after his "back radiation" initially heated the hotter source bar,...because were he to continue he would arrive at the situation where an ever increasing "back radiation" B+b1+b2+b3...would eventually arrive at a "Spencer China Syndrome" melt down temperature. Similar to a nuclear "melt down" without the use of nuclear fuel rods. Perhaps we have wasted our time and $ with nuclear power research and should start building "Spencer reactors" which can be kick started with a few Watts and then continue with "back radiation"
http://www.drroyspencer.com/2010/07/yes-virginia-cooler-objects-can-make-warmer-objects-even-warmer-still/
In Spencer`s "Experiment", "back radiation" disappears as soon as it has done it`s job convincing the reader and thus avoids the Spencer China Syndrome that would have to follow, unless we do apply the 2nd thermodynamic law that Spencer feels free to dismiss