Sanitas Vibrationum
Active Member
Photosynthesis lol. This thread is gold.
Can a light get too efficient
- Thread starter Uncle Reefer
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Sanitas Vibrationum
Active Member
What about PAR watts and heat watts. We got all these smart folks talking about btu's, space heater ect, but why ignoring an elephant in that same room - fucking weed 
It does consume energy to grow and it's ain't fucking heat watts that they use - it's a PAR watt's that needed.... I agree that 1w = whatever amount of BTU they claim, but we are talking about complex system here.
by the way 1000W at 50% efficacy of saltwater 6500K+ light will be even cooler than 1000W @ the same efficacy horticulture LED's and 1000W UV light will be even cooler
That spectrum plays a big role for us, tent growers - we don't want to heat up our plants with energy that aren't being consumed by the plant and as a result - heating up the leaf surface.
It does consume energy to grow and it's ain't fucking heat watts that they use - it's a PAR watt's that needed.... I agree that 1w = whatever amount of BTU they claim, but we are talking about complex system here.by the way 1000W at 50% efficacy of saltwater 6500K+ light will be even cooler than 1000W @ the same efficacy horticulture LED's and 1000W UV light will be even cooler
That spectrum plays a big role for us, tent growers - we don't want to heat up our plants with energy that aren't being consumed by the plant and as a result - heating up the leaf surface.
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wietefras
Well-Known Member
Still, you need to take it one step at a time and if people don;t understand the basics then you won't get anywhere.
For what it's worth, contrary to what you seem to assume, plants really don't make that much of a difference. Only a few percent of the light they receive gets converted into biomass. In the grand scheme of things that amount is actually insignificant.
Either way the point that watt for watt, the energy put into the room is the same is important be it a space heater or a lamp. Of course you get convection heat more easily out of a room, but the point is that the heat is there. You just have make sure you actually use it instead of sucking it out the room and discarding it.
WeedSexWeightsShakes
Well-Known Member
great thread but you guys really over complicate growing weed
NanoGadget
Well-Known Member
Or vent just enough of it to get your temps exactly where you want them. I use a bare minimum when it comes to extraction. I use just enough cfm to keep the air fresh and maintain a slight negative pressure. My temps happily sit at 80 to 86 and the plants adore it. That being said, my current space is small and this is what works for me. Even if I ran a sealed room I could run my ambient temp hotter with my QB because the canopy will be very close to the same temp. With HPS if my room is 85-90 my canopy and leaf temps are going to be well north of 100.
Again, thermodynamics aside, in real world application it works better for me and saves me money. Many could say exactly the same for HID and they would not be wrong. For some it gives them exactly what their environment calls for.
Again, thermodynamics aside, in real world application it works better for me and saves me money. Many could say exactly the same for HID and they would not be wrong. For some it gives them exactly what their environment calls for.
nfhiggs
Well-Known Member
The obvious solution to this conundrum is to REDUCE WATTAGE. More photons per watt means you use less wattage.
nfhiggs
Well-Known Member
A plant only absorbs a about 7% of the light hitting it. That's a small fraction of the total light produced.What about PAR watts and heat watts. We got all these smart folks talking about btu's, space heater ect, but why ignoring an elephant in that same room - fucking weed
by the way 1000W at 50% efficacy of saltwater 6500K+ light will be even cooler than 1000W @ the same efficacy horticulture LED's and 1000W UV light will be even cooler
JavaCo
Well-Known Member
Doesnt matter how much the plant absorbs since photosynthesis falls into the laws of thermodynamics. Really all this is moot since they are loosely using the closed system catch on the argument. We simply don't live in a close system as the earth loses heat to space. Even a grow room with a closed door and vents blocked off will bleed off heat thus making it not a closed system. They are only right if both lights are in a true closed system which is never going to happen unless someone is trying to validate the argument. But you know for sure the HID salesmen love this argument.
I think the more efficient lights are better for system efficiency. The energy saved can operate a humidifier that will add heat and remove humidity.
If more heat is needed, it can be done with a heater and a nice digital temperature control.
You said it hasn't been a problem before, what changed, the lights?
Uncle Reefer
Well-Known Member
I have been running SK600's for a year now and the plants are really beginning to go through water, about 25% more per feeding to keep them wet. Because of this, the RH is getting higher, it's not a problem, its still in a good range but it is running higher.
Ya, you are right the answer is to just run a dehuie.
About what has changed my organic game has gotten stronger I have a few new tricks up my sleeve, and I am using fewer bottles salts than ever.
This is really less of a problem more of an event horizon thought, about the nature of what environment controls are more important. Aws we get better gear the dehuie will become more and more important. Soon the days of having a cheep big box dehuie will be gone and everyone will have a high-end quest humming away instead.
GrowLightResearch
Well-Known Member
As a photon is absorbed by a plant some energy is lost as heat, but most of the absorbed energy is utilized by the plant. More of the energy of blue photons must be dissipated as heat than red.
So no, not all the photons become heat again.
Or ya could up your game by learning to grow with higher humidity. Keep the stomatas open to the max!
Just the vast majority.
So with that logic the more plants you have in a room the cooler it runs? More plants more heat absorbed...I don't think that's how it works
Schalalala
Active Member
Then tell us, how does it work in your world?
GrowLightResearch
Well-Known Member
The photons utilized do not produce heat. So yes, more plants means cooler, not a lot but cooler.
Deep red is the most efficient.
True, maybe as much as 15% if using narrow band LEDs. 25% if using only deep red, but that's not realistic.
Still, no such thing as too much efficiency.
Schalalala
Active Member
....cause they produce weed! WICKED!
nfhiggs
Well-Known Member
Photosynthesis simply "stores" some of the light energy as potential chemical energy in the form of plant matter. And yes, as a matter of fact, more plants is more heat absorbed - but the thing is, its a VERY small portion of the total energy that is fed into the lights. Most estimates I've seen say the plant absorbs and uses something on the order of 7% of the light falling on it - and a significant portion of that photon energy is re-emitted as the photons are converted to the frequency the chloroplast uses. Additionally, you have to consider that not all of the photons emitted even reach the plant. I would guess that, at best you are looking at the plant making a 1-3% difference in the total.
Room usually runs cooler with less plant mass like after a leaf strip it seems to get a little cooler but I'm not measuring heat at very many points. I will pay closer attention to temps next time I defoliate.
GrowLightResearch
Well-Known Member
Very spectra dependent. The maximum oxygen evolution utilization, at 680nm is 27%. Very little is absorbed between deep blue and deep red. The majority stored, is stored as glucose, which does not amount to much except in sugar cane. A good percentage of blue is dissipated as heat because it has 50% more energy than red. Very little green yellow orange is absorbed.
Fluorescence, the photons re-emitted at a higher wavelength, does lose a little energy in the wavelength conversion. Hopefully that photon is used by a leaf lower in the canopy. Fluorescence only happens in red spectrum.
You are correct with the spectrum typically used. A very small percentage is utilized.
Plants use photons mostly in photochemical oxidation of water, and to reduce carbon dioxide to organic carbon compounds, typically sugars.
The biochemical production of secondary metabolites (e.g. cannabinoids) by these carbon reactions is where things get interesting.
Mostly off topic. Except maybe how the efficiency of photosynthesis is affected by photorespiration in the biochemical carbon reduction. I do not understand chemistry well enough to understand biochemical processes.