jarvild
Well-Known Member
But sunlight emits 50+% of it's energy in NIR or IR.
The Ideal spectrum.
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SSGrower
Well-Known Member
Yes, but consider that energy is used to moderate the temperature of the entire earth above the absolure zero of space. If we start at 60F the energy differential would be less, and the only mass we actually want to increase the temperature of is the plant itself.
ChiefRunningPhist
Well-Known Member
The plants still get 50%+ (just parroting earlier figure, idk actual %) IR regardless of the temp of space. I think I'm missing something here..
ChiefRunningPhist
Well-Known Member
Ill check it out, curious what area that intensity is applied..
SSGrower
Well-Known Member
Are these figures what is incident on the earth's surface?
IMO matching the ratio is more important than matching the ammount. Keep in mind that IR from the sun is still getting into the grow area even though we cant see visibil light from the sun.
SSGrower
Well-Known Member
When I say ratio, what I really mean is ratio of photonic energy that is available to the plant. This goes for the whole spectrum with variances between wavelentgh ranges. This is why we should be targeting ranges of spectra rather than specific nm peaks of leds. As it seems current technologh does not allow for a nondiscrete integration of spectral values, we cannot currently create a great enough spectral resolution with individual leds amd must rely on color blending and peak averaging. This also points to the greatest advantage of phosphor coated white leds over monos, the averaging affect (or is it effect?). Incorporating luminous refractivities of other materials amd capitalizing on the natural frequencies they emmit will be crutial to future led development.
ChiefRunningPhist
Well-Known Member
Just a little tidbit haha, IR is emitted by everything, including ice!
I'm not sure where the magic in the making is, I'm not discounting ratios, but even if dealing with ratios, the sun on average has a much greater percentage of IR than what we ever think about when using LED.
Heres an SPD of the sun..
ChiefRunningPhist
Well-Known Member
Right!
I wonder if there are some previously negatively thought of WV's that are actually important. If the WV at certain IR is "photonic energy available to the plant."
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Look into chlorophyll-f, FR (730nm), and PSII..
I'm not sure yet on the implications but came across a paper which found chlorophyll f to be driving PSII all by itself, without the help of chlorophyll a. This is contradictory to what was previously thought which was chlorphyll f was only an energy store for chlorophyll a. In the study the FR adapted specimens, or specimens placed under FR light, produce more chlorophyll f.
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SSGrower
Well-Known Member
Hit right where I was going with it. If it is all around us, then what form and how much to suppliment with led or any other source is the question.
Can I get a better cost/benifit by using another source? Technically I dont think so, all other sources have more transitional losses. I think the same is true for uv, just that because the cfl killed the led in the 90's we are behind just as with electric cars.
jarvild
Well-Known Member
It's more of a question of what the plants use. What I'm saying is the plants in nature are exposed to a high percentage of the NIR spectra on earth so have acclimated to being in the presence of that not whether they use it or not.
ChiefRunningPhist
Well-Known Member
IR is the same thing as light, both EM radiation, one's just lower energy. The lower energy, the longer the wavelength. A ceramic heater radiates IR more efficiently than a light because the ceramic heater isn't having to add extra energy to excite electrons to the point of visible light emissions, they only have enough energy to radiate the EM as IR, if you see glowing, some of the energy is at a higher state than IR and thus you get "glowing," or visible light. So to produce IR you're actually putting less energy into something vs if you wanted that something to produce light. I don't know the most effecient way to create IR. When I've looked the best and most effecient way I've found people recomending is running current through a resistor. I think if you're trying to determine specific WV's as whether or not they are viable, that narrow banded LED could be a useful tool. I think they use Xenon lamps rn in the labs to dial in the WV when targeting specific WV..
If trying to replicate the sun then a heating element with a wide IR band might be your best bet. Idk what WV, or how much, or long, or in what ratio to others. Perhaps just running the LEDs "hot" would be more effecient than adding a heater...
EDIT:
I'm adding IR to mine so I can say I have it, lol, and also because I'm curious if it will increase LST, and I dont want to overheat my LEDs to add IR. The 850nm figure is a complete shot in the dark and have no idea how, or if it will have any effect.
Btw here's that paper I was referencing earlier..
https://www.researchgate.net/publication/326568517_Photosynthesis_supported_by_a_chlorophyll_f-dependent_entropy-driven_uphill_energy_transfer_in_Halomicronema_hongdechloris_cells_adapted_to_far-red_light
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ChiefRunningPhist
Well-Known Member
They are finding photosynthesis being driven in WV as high as 742nm+.
https://science.sciencemag.org/content/360/6394/1210
https://www.researchgate.net/publication/272192737_Chlorophyll_f-driven_photosynthesis_in_a_cavernous_cyanobacterium
I know, I know, bacteria, how translational? From my PhD neurogenetisist friend, she says it's very translational...
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SSGrower
Well-Known Member
Or running an led or set of leds "hotter" than the others? I dont think 2700K white is cool enough, seems 1750K is comercially available? Plus running cobs softer shifts (basically unquantifyably tho) to a cooler spectrum. It seems a fine model considering the heat management system and entire radiation profile is needed to realy make an informed decision? Also shows a nedd imo to obtain broader spectral data for the leds, mfr's dont outright do this i think because of the high dependance on the efdeciency of the thermal managment.
IMO a well blended white base and a few of the longer WV reds and targeted uvr8 is the wayto go. I want to look for a simple and effecient way of doing what I have in my head with adjusting led drive current. I have been avoinding tackling pwm with the arduino because my lack of programming knowledge, I am curious if the "d" series meanwell driver and associated control software would be up to the task?
ChiefRunningPhist
Well-Known Member
As color temp goes down ie from 6500k down to 2700k, the spectrum shifts "hotter." The longer the WV the greater the "heat" felt. (Because we're mostly made of water...)
And ya, I'd have to agree, the plants' response to all EM is what's needed to make an informed decision on what the future lighting industry SPDs should be, at least when regarding MJ.
The effeciency of LEDs is described as visual light emmision or photonic emmision vs the power supplied. Whatever power isn't used for visual is expelled as heat or IR. If you expanded the SPD to include all EM including IR, the chip would be 100% effecienct (negating kinetic). The effeciency of the thermal management is part of a greater system and not dependent solely on the chip. In contrast, how much heat/energy needs to be managed intially is dependent on the individual chip, or the chips effeciency. A wide SPD of LEDs would only show varying degrees of IR over time (as it heats up) but wouldn't be damning to the initial effeciency number, rather it would support the initial effeciency claim. What I'm getting at, is that a wider SPD showing IR emmission only confirms that the chip is X% efficient, we already knew that the other Y% was being emitted as waste. You could be right, that they don't want to show wider SPDs because of the way they are marketed as being so effecient, but I think it'd be hard to really determine actual IR SPD considering its dependent based on what the LED is mounted on. If the LED is transferring thermal to a board or a heatsink, the board or heatsink will emit as much IR as the LED gives it thermally. Idk maybe you could determine WV, it would be ambiguous and not a single WV, but your amount of IR or quantity emitted is directly related to temperature. Hmmm... White LEDs are not generating IR through their design though, only through their operating temps. This is key to note. This is in direct contrast to an incandescent or HID, which heat up a filament to a certain degree and once the filiment gets hot enough it gives off visible light, that's why all the IR. An LED isn't heated up to produce light, its electrically exciting doped semiconductors to give off light at certain WV as the semiconductor electron drops from higher energy to lower energy.
FF to 2:27 to where it talks about basic diodes..
EDIT:
This video explains the diode a little more focused at LED..
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TEKNIK
Well-Known Member
One of the easiest ways to add IR is to use a Halogen light bulb, flower farms to this day use incandescent light bulbs to increase flowers. IR is broad, 730nm is only at the beginning of IR. Leds are not efficient above 730nm. Going beyond 730nm the leds are used for security purposes ect. They are not efficient but used for the narrow spectrum.
ChiefRunningPhist
Well-Known Member
LEDs are more effecient than incandescents at producing IR for the fact that they waste 0 energy with visible emission.
730 is NIR or near infrared. There's varying degrees of IR.
ChiefRunningPhist
Well-Known Member
You might as well say an LED that isn't producing light and is flowing current, is 100% effecient at producing IR. The only other form of energy being consumed is by the chips expansion and that's kinetic. So minus the kenetic, if an LED doesn't produce light, and it is accepting current, it is 100% effecient at producing IR.