After the essays in May on mirrors and light bulbs, I’ve been regularly poked and prodded via email for not wanting to engage “the slayers” anymore, or to do that “third experiment” I mentioned in May. I long ago concluded by my experiences afterwards with “the slayers” that it is a waste of time and effort to try to explain anything to them. Curt Wilson, who did the second experiment and was planning to do the third, has come to the same conclusion, as have many others.
I have to give them credit though, they are entertaining. When I saw this profoundly ridiculous rebuttal (reflectional denial) at their headquarters while arguing over Willis’ Steel Greenhouse post, I just had to share it.
LOL! That’s the “slayers” in nutshell right there. No better example of the absurdity of their position exists in my opinion. Epic.
WUWT regular, Duke physicist Dr. Robert G. Brown has been trying to talk some sense into them over at Principia Scientific. I keep telling him he’s being sucked into a time and energy sink like gravity around a neutron star. Just as it is a good policy to steer clear of neutron stars, so it is with these folks who are incapable of assimilating the real world of physics, but live in an alternate reality of absurd second law constructs.
So, that’s why I’m not bothering anymore, when you have reflection denial statements like the one above, why engage in a pointless dialog with the hopelessly lost who don’t want to learn anything? Thank goodness for my spam filter.
For those that might care, keeping the filament of a lightbulb within its optimum temperature range increases its life, by limiting hotspots and thus tungsten evaporation. Putting an incandescent bulb into a reflector housing not designed for it will in fact increase the filament temperature, increasing tungsten evaporation and deposition on the inside bulb glass surface.
See: http://www.lightingassociates.org/i/u/2127806/f/tech_sheets/FAQs_Reflector_Design__Why_is_it_important_.pdf
Tungsten evaporation from hotspots is why standard incandescent bulbs eventually fail.
Bad typing S/B: …reflection to and from the surface.
“highflight56433 says:
July 19, 2013 at 7:10 am”
Not the same!
Jim A says:
July 19, 2013 at 5:57 am
From the viewpoint of a self-taught engineer: >> IF << it were possible to tune a parabolic light reflector to the entire tungsten filament there would be little effect at all.
………..
Jim, you need to finish the self teaching. Parabolas focus parallel light , what come off a bulb is not parallel so you're going to need some pretty serious "tuning". Also a parabola is a two dimensional curve. You probably meant paraboloid.
A polished hemisphere would be much better. Perhaps you should look up the temp coeff of the resistance of tungsten at the appropriate temperature and let's say 50% of the outgoing heat and light gets reflected back work out the new equilibrium temperature of the the filament would be.
Then you may be able to make an educated statement as to whether there will be "little effect" or not.
I could swear there was something about the mirror not making the bulb brighter, as for hotter, you’re putting in a given amount of power, you’re not letting it dissipate effectively, not sure what this is a proof or disproof of.
We see the weather on the sun as the sun’s climate changes from season to season. Same on planets with an atmosphere. A function of uneven temperatures. The green house has a limit, just as any other intervention to energy flow.
Patrick says:
July 19, 2013 at 7:16 am
“highflight56433 says:
July 19, 2013 at 7:10 am”
Not the same!
Agreed, just as the greenhouse experiments are not the same. I think that is the entire point. 🙂
Anthony, off topic, UK gov announce fracking tax breaks, done as parliament goes on summer holiday
http://tallbloke.wordpress.com/2013/07/19/shale-gas-uk-government-unveils-tax-break-plans-and-runs-away/
A good way to extend bulb life & save some electricity is too add a diode in series with the filament. They make flat diode pads to do this but it is just as easy to do (and way cheaper) at the switch. So instead of a 25 watt light bulb use a 60 watt with a diode for extra bulb life. Dimming of course also reduces power usage and adds life. However they make long life bulbs (see 1000bulbs.com) although they have less lumens/watt. They also sell a carbon filament bulb that looks much like the original incandescent (only rated 2000 hours though).
The problem with some low quality CFLs and LEDs is that although they are rated for long life, that may only apply to the light emitter. If the electronics are of low quality then they may give up well before the rated life. In addition the bulb styles and light are not always as pleasing and are more expensive up front. I have bought my incandescents on line when on sale and in bulk for a special rate so that they cost even less.
” AndyG55 says:
July 19, 2013 at 4:45 am
Suppose the reflector is actually matt black rather than a normal reflector. I’m guessing that the matt black reflector will get hotter than the normal reflector and the filament will not get as hot.
Reflection of heat and heat transfer between objects is two different things completely.”
Right.
Only a few have every claimed CO2 reflects IR.
Another aspect is distance involved with reflection or re-radiated wavelength.
But all of this not the main issue.
The fundamental aspect is idea that only the radiant effects of greenhouse gases
can increase the average temperature of a planet. Which should be seen as
obviously wrong- as there are other ways to increase average temperature other than
involving the radiant effects of gases. And it seems obvious that radiant effect of transparent liquids [mainly Earth’s ocean and the droplets of water in clouds] have a significant effect and would major part in increasing a planet’s average temperature.
Other than any radiant effects, the specific heat of the planets surface should also have
dominate affects upon a planet’s average temperature.
In other words, greenhouse theory claims that a planet with a atmosphere and same reflective
properties as Earth would be 33 C cooler without greenhouse gases- and that only greenhouse gases can cause an increase of 33 C to Earth average temperature.
For example I believe [because their is clear evidence] that the type of lunar surface, rather than than color or reflective nature of material affects the average surface temperature of the Moon.
Or solid rock is known to retain it’s heat longer and lunar regolith.
So clear evidence that the heat capacity has very noticeable effect and that the insulative
properties of fine powdery lunar regolith as a cooling effect on the Moon average temperature.
Or material which conducts more heat from the heated surface would be a warming effect on the Moon. This is not radiant effect, it’s conduction of heat. Or transfer of heat, which once transferred takes longer to lose it’s heat back into space.
Or concrete or asphalt pavement absorbs more heat than sand, and takes longer to become cooler and this has nothing to do with radiant properties of gases. Or because of crazy idea that the warming possible is called greenhouse effect, pavement is greenhouse effect. As are oceans and other bodies of water.
So, I am willing to entertain an idea that greenhouse gas [mostly water vapor] may cause 5 to 10 C of the 33 C. Not probably less than 1/2 of “greenhouse effect”.
And if had to pick largest “greenhouse effect” the obvious factor seems related to the liquid transparent oceans. And next factor is heat capacity of an atmosphere.
Or greenhouse gases are not the major or as claimed sole factor of warming or increasing
earth’s average temperature.
That reflector link relates to fluorescent lighting – no filament, no tungsten. Just saying.
REPLY: Yes but the point about thermal considerations of reflectors is still valid and that was my reason for using it. – Anthony
I am sorry, I dont see what is so transparently stupid about the suggestion that the filament might evaporate; those old 16mm projector bulbs didnt used to last long.
Are you suggesting that if one took a spherical-ish bulb and surface silvered it that the filament would remain at the same temperature?
Maybe I am as dim as the slayers!!
Absolute twaddle. Your eyes detect light, which was reflected off your face from some high-energy source, bounced off the mirror with little loss, and back to your eyes. Nothing at all to do with energy output by your face/
If you are going to attack the rubbish that the SL*Y*RS say then at least use a reasonable argument.
Incandescent filaments are/were made to last 2000 or 1000 or 500 hours. The difference is that the filament in the 500 hours lights are made a little thinner and therefore get hotter and give a “whiter” appearance and have a slightly higher light yield at the cost of the life expectancy.
Any hindrance of the light and/or heat output of the lamp that is reflected to the bulb will increase the filament temperature and shorten the lifecycle of the lamp. That was proven in the second experiment, where the lamp was covered with a foil cube, the current dropped with 0.7 mA. That is because a hotter filament has more resistance and therefore draws less current at the same voltage.
OK, my comment has successfully come through with a 2 hours dalay. I am writing this to test if I am still under pre-moderation, and if yes, please, cancel it to make a real time conversation possible.
Get a worklight-style bulb-on-a-cord.
Stick it into sand bulb-down.
Light it.
Then explain why it burns out so fast.
Stick a thermometer down in the sand, and a multimeter measuring amperage on the lamp.
The sand won’t be close to the filament’s temperature before the filament will be toast.
johnmarshall says:
July 19, 2013 at 5:36 am
“OK Anthony, you have faith in the GHE so patent a process using this effect to generate energy. This is just a simple challenge to you and your GHE friends.”
keywords IR PV IR antennae rectenna IR solar cell
http://www.sciencebuzz.org/blog/nanoantennas-change-heat-electricity
Well there is a (small) element of truth, in the silly statement.
Back in the old days, (as they say), people had things called slide projectors, designed to throw magnified images of Kodachrome color slides onto a distant screen. Kodak, Bausch & Lomb and many others made them (I still have one.
Almost universally, these projectors used a special 500 Watt incandescent light bulb to operate them.
The lamp typically had a double separated straight strand of coiled coil filament. The Tungsten wire was extremely fine, and using the coiled coil, got a lot of wire length in a compact space.
This lamp, mounted in the housing with the two filaments side by side, vertically, and parallel to the slide plane.
A condenser lens in front of the bulb roughly collimated the light beam. It did not focus on the slide plane.
With that arrangement, only a small fraction of the light (25%) got to the slide.
The housing included a concave spherical mirror behind the bulb, with the filament center, at the center of curvature of the mirror. With that exact arrangement, the mirror, forms a 1:! inverted image of the two filaments, actually on each other. Each filament’s image fell on the other filament.
This is undesirable.. The mirror (or lamp) had a fine adjustment arrangement, that translated one or the other sideways, parallel to the silde plane. In the new bulb replacement process (quite often) , the setup was adjusted so that the two filaments, and the two images interleaved, so that one image fell between the two filaments, and one filament fell between the two images. With a high reflectance mirror, the two images are essentially the same brightness as the two filaments; at least within the solid angle that the condenser lens could accommodate.
So with no slide in place, one could focus the projection lens, so that it focused on the filament plane, instead of the slide plane. So on the screen at some useful distance, one got an image of four filaments, which then enabled the correct offset of the lamp or mirror. to get four equi-spaced filament images..
If the projector used a cheap metal mirror (Aluminum), it also reflected IR very well, so if you misaligned, and got the filaments imaged on each other, then the “heat energy” going backwards, got returned to the filaments, so the filaments didn’t cool as fast as they were supposed to and they ran at higher Temperatures.
Better projectors used a “cold” mirror, which selectively reflects visible radiation, but transmits IR wavelengths so they escape out the back of the projector.
Running the filaments too hot, increased the rate of Tungsten evaporation, and there would always be sections of the filament, that were finer diameter than the rest of the filament. They would run hotter, and evaporate faster, so that made them even thiner, further accelerating the selective loss from hotspots. The filament would eventually fail from mechanical fracture of a thinned region of the filament; NOT from total evaporation of the filament. The differential thinning is actually very small, but the Temperature increase is amplified.
I think those bulbs only lasted about 250 hours or so even under ideal conditions.
gbaikie says: July 19, 2013 at 8:05 am
“The fundamental aspect is idea that only the radiant effects of greenhouse gases
can increase the average temperature of a planet.”
This is a strawman argument. No serious scientist would say such a thing. LOTS of factors influence the surface temperature of the earth (and you go on to point out some of them).
Basically, these other factors (like heat capacity and the rate of rotation) can help bring the “actual average surface temperature” up to the “effective blackbody temperature”. A rapidly rotating, high heat capacity; emissivity = 1; albedo = 0.3; no-GHG planet could have a surface temperature that approaches an average of 255 K. But neither heat capacity nor oceans can change the laws of physics that limit the effective BB temperature to 255K. If you make the planet spin more slowly or reduce the heat capacity, the average will drop below 255 K.
Even adding GHGs does not change the effective BB temperature of the earth — that number is still 255 K. That is what an IR thermometer aimed at the earth as a whole from out in space would read. What DOES change is the effective radiating level — the “surface” of the earth if you will. With no GHGs, the “radiating surface” IS the actual surface, and the actual surface is limited to and average of 255 K (or less). With GHGs, some of the “radiating surface” is high in the atmosphere. In this case, some average of (the atmospheric temperatures and the actual surface temperatures) is limited to 255 K (or less). Since the atmospheric radiation aften comse from areas colder than 255 K, other areas like the the actual surface can (and must) be above 255 K.
Dr. Brown needs to face the fact that “there are some people you can’t help”. This is the same problem that government social workers have. Indeed I applaud his effort but realistically many of these people are beyond help. They are too ingrained with liberal propaganda to recognize the truth or in some cases to even process the concepts being presented. Sad really.
Definitive experiment: set three matched large (~10 gal) aquariums out in the sun with identical thermometers in identical relative positions. The difference is that two have a transparent (glass or plastic wrap) cover/convection barrier. One of these is enriched with CO2 (a bit of dry ice, allowed to sublimate and equilibrate).
The temperature differences between the two will compare the contribution to greenhouse heating due to the convection barrier and the contribution due to CO2.
The definitive statement of the physics if from Goody and Yung ‘Atmospheric Physics’, Ox. Ac. Press.
The monochromatic rate of heat accumulation by matter is the negative of the Divergence of the monochromatic radiation flux density at a point.
This means heat transfer rate = -Delta I where I is the irradiance. So, ‘back radiation’ cannot exist.
It is why you use the difference of two S-B equations but in neither case is the irradiance transmitted power.
Most scientists and engineers fail to understand the negative sign or that the pyrometer output which is the potential flux to a sink at 0 deg K is not an energy flux, but a potential energy source.
Eventually the rest will catch up. Talk to the pyrgeometer manufacturers and they will tell you exactly what I have written here. There is no ‘back radiation’; the Trenberth Energy budget has wasted 100s of man years creatinbg a perpetual motion machine.
Is it that they do not want to learn, or is it that they are so stubborn to push an agenda – no matter how foolish it makes them look!
“””””…..Greg House says:
July 19, 2013 at 6:27 am
You could have quoted my very clear statement on impossibility of “back radiation warming” from the same page as well, it is relevant:
“Radiation reflected back to the source can not have any effect on the temperature of the source……””””””
It may be relevant, but it is also nonsense.
In the case of an incandescent source powered by electricity, the electrical parameters, including high Temperature resistance, determine how much electric power is being delivered, to heat the filament.
The equilibrium Temperature reached then depends on the rate of energy loss, mainly by radiation. There will be “heat energy” conduction from the ends of the filament to the mounting hardware, which acts as a “heatsink”.
If the filament were to be immersed in high purity water, it wouldn’t get as hot. (we don’t have to assume an actual vacuum or gas filled light bulb filament).
So reflecting some of the otherwise escaping radiant energy (of any wavelength) back to the filament, will result in some of it being absorbed and some reflected. The amount absorbed results in a net reduction of the rate of energy loss, so the equilibrium Temperature will settle at a higher value. This higher Temperature filament will likely have a higher resistance, so the electric power will drop.
In the case of an LED die, the emitted radiation is narrow band. If you reflect some of that back to the chip, some will be reflected, and some will refract into the chip, and rattle around in there. The LED diode junction, also happens to be a very efficient photo-detector (solar cell) at the same wavelength range that was emitted. So photons absorbed by the material, will result in electron-hole pairs being generated, and swept across the junction to create an electric current. This current is always in the opposite direction to the original applied current, but the device is usually current driven, so the result is the current remains the same, but the terminal Voltage increases, just as if the internal resistance has increased (it has).
So with the same current drive and a higher drive Voltage the applied power is increased, and the chip will get hotter.
*sigh* Here we go again.
johnmarshall says (July 19, 2013 at 5:36 am): “OK Anthony, you have faith in the GHE so patent a process using this effect to generate energy.”
Big Don says (July 19, 2013 at 5:51 am): “I, for one, would like to see a third experiment. Unlike most WUWT readers, I’m not yet fully convinced that the slayers are fundamentally wrong.”
Greg House says (July 19, 2013 at 6:27 am): ‘You could have quoted my very clear statement on impossibility of “back radiation warming” from the same page as well…’
AlecM says (July 19, 2013 at 10:39 am): “So, ‘back radiation’ cannot exist.”
Dr. Spencer has illustrated the basis of the so-called “greenhouse effect” with his classic “Yes, Virginia” thought experiment. Just so we’re all on the same page and there are no misunderstandings, John, Don, Greg, and Alec, could you please read Dr. Spencer’s article, if you haven’t already?
So far it’s just a thought experiment, but one of Dr. Spencer’s readers may soon do it for real, or at least a variant thereof. John, Don, Greg, and Alec, just to make your positions crystal clear, could you predict the outcome of the “Yes, Virginia” experiment if/when it’s done for real? Would the temperature of the heated plate increase, decrease, or remain the same in the presence of the unheated plate, compared to its absence? (Greg, I know I’ve asked you this before, but I don’t recall you anwering.)
If it will help, one of the blank-ers has given his answer at a-site-I-must-not-link. Google “No, Virginia, cooler” to find it. 🙂