WeedSexWeightsShakes
Well-Known Member
It’s all about growing to your environment. Some make it more complicated than it is.
What would you recommend to replace a 1000w HPS in a 4x4 tent?
- Thread starter Dr.Pepper99
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Mcnally12
New Member
I have a 4 x 4 x 8 foot grow tent. In there I put a 1000 Watt LED viparspectra and a 600 watt LED Vipar side by side works beautiful have a 6" inline exhaust with 24" carbon filter also 1 fan in corner to circulate air. I have had 3 setups and this by far the best results I've ever had. Good luck and Grow on my Brother.
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Prawn Connery
Well-Known Member
Must have touched a nerve - selective answers are a dead giveaway.
I notice you didn't address the point about convective heat exchange being a function of surface area and medium (air or other) velocity, so blanket statements like "led produces more convection heat which simply rises away from the plants and is easier to extract" are not accurate.
A 600W HPS bulb can reach 450C. You can duct as much heat away from that bulb as you can pump air over it.
And you can't have an each-way bet by saying on the one hand . . .
. . . then on the other:
The point is, even if you define "radiated heat" as the greater amount of IR produced by a HPS bulb, the fact all the other spectra "eventually gets converted to heat" means one of your statements is wrong.
If you don't know how to basically quantify a statement, you basically shouldn't be making them.
Prawn Connery
Well-Known Member
I don't dispute a lot of what you are saying about the interaction of different types of thermal radiation emitted by HPS vs LED - I've used the same argument myself (funnily enough, against Yodaweed). It was merely pointed out that visible light is thermal energy, too - not just IR.
JSheeze
Well-Known Member
Well the plants sure don't grow by themselves.. majority of visible light photons absorbed are by the plants, ... So they can grow...
And Fuck it one last time..
Because the tent is not a closed system, because its part of a greater room, the rate at which the energy is converted into thermal radiation matters. The slower the time it takes to heat up, the less thermal gradient or the more equilibrium the system is at. Ie most of the reactions are at the same level, you don't have a big differentiation between 2 areas of the system. The systems total energy is the same, but the difference or thermal gradient between 2 of the areas are drastically different in terms of equilibrium. Because LEDs convert less energy to thermal radiation initially and due to their heat sink thermal dissipation rates they produce the same amount of total work on the system as HPS but much more evenly absorbed leaving less of a thermal gradient or disequilibrium of the system although the total work is the same. And finally the room isn't a closed system it transfers energy as well...
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Prawn Connery
Well-Known Member
BUT . . . 600 HPS is rated 50% higher wattage than 400W LED. The maths (energy required to raise temperature from X to Y) isn't as straightforward as that, but you get the picture.
Incidentally, this is where wietefras copied his radiant heat vs convection heat statement from. The only problem is, he failed to mention that a lot of the HPS "convection heat" is trapped under a batwing hood. The "radiant heat vs convection heat" statement is a bit of bullshit when you actually look at the setups of the two lights in the above video.
EDIT: Incidentally, this is a good example of why vertical HPS works so well. More efficient use of emitted light (not just PPFD measured after it is reflected and has travelled a greater distance), as well as better ducting (through unimpeded convection - even better with a floor fan blowing over the bulb).
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wietefras
Well-Known Member
Yes your nonsensical posts make me cringe.
Seriously, someone stating that "light is heat" and then goes on to pretend he's some authority on the matter. It's just sad.
No it's not. Stop being such a dumbass douche.
You can complain I don't actually try to dispute your nonsense, but that's because it's pointless to even try. Really, everything you posted is either utter nonsense or a misunderstanding on your part.
wietefras
Well-Known Member
Only a small percentage of the light is actually used for photosynthesis. Depends on who you ask which estimate is used, but it's somewhere between 4% and 8%.
WeedSexWeightsShakes
Well-Known Member
Is this how you actually communicate to people in real life or just on Internet forums?
JSheeze
Well-Known Member
Ok and also only a small percentage of light is realized as "heat" inside your tent. It's not the visible light needing to be mamaged, its the tech...
Total work is the same, its how its distributed. Heat sinks, efficiency, spectrum make all the diff.
We used to heat houses with one central fireplace. Now we use HVAC and heaters. The HVAC acts as a heat sink distributing hot air evenly over the whole house. The fireplace acts like HPS heating the house from one point. This is one of the advantages of LED over HPS. They have much better heat diisipation at the source.
Because the walls aren't insulated this evenly distributed heat is easily absorbed by the large surface area of the tent walls as air interacts with it.
Furthermore LED doesn't emit IR so you'll have less energy needing to be dissipated at the source compared to HPS which emits IR.
At the rate that light interacts with Mylar to produce thermal radiation the only source of heat needing attention is from the IR emitted by certain lights and the operating temps of light/tech.
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Yodaweed
Well-Known Member
If 8% maximum light gets turned into plant growth, that means 92% is turned into heat. that's why all lights are equal watt for watt for heat output in an enclosed area.
JSheeze
Well-Known Member
Your little off but close.
Tents are NOT closed systems.
The energy in equals the energy out BUT more of that energy is realized as visible light with LED compared to HPS with more IR. Also the inefficiency of HPS to LED produces more "heat" as well initially. If the light is reflected then it isn't absorbed and there isn't an increase in thermal radiation. Nothing lasts forever so all light will eventually interact with something that is able to absorb it but depending on many factors it happens much less efficiently than IR is able to produce "heat". We don't use white light as incubating lights, we use IR, the white light is very inefficiently coverted to "heat" compared to other methods of existing energy to maintain a thermal gradient. If you could focus that light, with a magnifying glass you could see a thermal gradient easily, but without that lens the light is equally distributed and so not much gradient is realized without taking all the light and focusing on one spot (because when not focused it is acting equally on the surroundings, same amount of energy just pushed onto a much larger surface area resulting in small universal changes instead of dynamic gradients). If you get your light to close to the plants its like focusing a mag glass, but like I said the real world difference is all in the temps of the tech, heatsink, and spectrum of the light, effectively making LEDs "cooler" while still having the same amount of work done on them as HPS (1KW vs 1KW).
When people say 1kw is 1k its misleading because the rate that which energy is coverted into heat matters. The tents aren't insulated so when comparing 1KW to 1KW its an incorrect assumption that the tent temps are going to be the same using 1KW LED vs 1KW HPS, so when designing lights and light systems its NOT accurate to assume that LED is equally as "hot" as HPS.
Principally speaking the energy in equals the energy out but because it's not a closed system you can't just subtract 8% from 100% and assume a vaccumm or absolute walls ect. You can't assume that the tent isn't part of a larger system. If you're going to look at the system as an Energy in vs energy out situation then you'd need to look at your house insulating factor, the outside air temp, the room insulating factor, the room air temp, rh, blah, blah, blah...
Rates matter
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JSheeze
Well-Known Member
Prawn Connery
Well-Known Member
Haha. He's an internet warrior - give him a break. I'm sure he's not big enough to talk to people like that in real life.
He's hurt because he got caught out on his double standards and the fact his "expert opinion" is based on someone's else's Youtube comment that's flawed in the first place, because they failed to notice the HPS was under a hood, trapping heat.
Which is why I never used hoods when I grew with HPS.
The reason Mr Fragile Ego can't answer is because he's parroting someone else's opinion. This is how convective heat ducting works in the real world - how else to explain why these plants didn't get burned whilst so close to 1200W of HPS (there is another bulb hanging below this one)?
Where is @wietefras's "radiated heat" in this picture? I don't see it - do you? What I see are plants that grew as close to two bare HPS bulbs as most guys here have their LEDs. In fact, closer. With consistent (true) yields in the 1.3-1.4gpw range (which is not bad for coco run-to-waste).
Here's what the plants look like when you take them out - no burning or bleaching. OK, maybe the odd fan leaf tip . . .
I know light burns, because it's something I contended with when I first started growing under LED and underestimated, considering how "cool" the lights felt. This is true "radiated heat" (visible light) - not IR. It's what happens when excess light energy can't be converted via photosynthesis, reflected or quenched. You will sometimes notice a similar effect when you take a shaded, yellowing or light green plant out into strong sunlight - there is not enough chlorophyll to absorb it, and so the plant bleaches.
And another photo just because I can. We're here to grow weed, right? Anyone can hurl an insult.
wietefras
Well-Known Member
That's how I communicate with pretenders like prawn. It's just obnoxious how he keeps spreading his nonsense without accepting any reason or acknowledging that he's clueless.
You can give people a few chances, but he just keeps doing this. It's pointless to actually try to discuss with him. Whatever we say, he just piles on more shit on the heap.
But you are right, I'll put the idiot on ignore. It's not my problem that he continually posts bullshit.
wietefras
Well-Known Member
Sorry, this is just too depressing again. So one more post wasted on the swine.
Try keeping a thermometer under an HPS bulb and then under led. See which one gets hotter. And yes make sure light intensity and such are the same.
HPS emits a load of IR (above 800nm). Everybody who knows anything about lighting knows that. Even if you don't "know" it you can feel it.
Top is led, middle is led mixed with HPS and bottom is HPS. Notice any difference in the IR range of the spectrum?
Anyway, on ignore you go. Really don't need to see this forum soiled by your stupidity.
Yes you don't see heat. Are you really that dense?
Try keeping a thermometer under an HPS bulb and then under led. See which one gets hotter. And yes make sure light intensity and such are the same.
HPS emits a load of IR (above 800nm). Everybody who knows anything about lighting knows that. Even if you don't "know" it you can feel it.
Top is led, middle is led mixed with HPS and bottom is HPS. Notice any difference in the IR range of the spectrum?
Anyway, on ignore you go. Really don't need to see this forum soiled by your stupidity.
wietefras
Well-Known Member
That's just one of the steps and in every step there is an efficiency which is not 100%. Overall from emitted light to biomass it's only a few percent.
:edit: geez it's even mentioned on that wiki page!
So they go with max 4.3% for "typical" plants and max 2% for crop plants.
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Prawn Connery
Well-Known Member
Ah, the keyboard coward - posting insults, then running to hide behind his ignore button.
That is the measure of your character, I guess.
Everyone knows HPS puts out more IR than LED - just as everyone knows plants (and all other living things) need warmth to survive. That warmth can be in the form of convective or conductive heat, or converted IR or visible light energy.
I showed real-world examples of LED light energy being converted to heat, and of HPS convective heat being removed, leaving mainly IR.
Clearly the remaining IR did not have much of an adverse impact on my plants, so I would suggest it is somewhat overstated on your part.
The problem is, you always use selective information and never quantify it. Here is another graph, from the same source, which is somewhat different to yours.
I'll just remind everyone here that to read these graphs, the heights of the peaks are relative to the area under the curve, which tells you exactly how much of each spectral group is being emitted. In the case of IR (which incidentally starts at 700nm), as a percentage of the area under the curve, it is minor compared to the combined area of all other spectra.
Don't let people like wietefras try to baffle you with bullshit - real-world examples work in the real world.
And people who can't back their shit up usually run away . . .
That is the measure of your character, I guess.
Everyone knows HPS puts out more IR than LED - just as everyone knows plants (and all other living things) need warmth to survive. That warmth can be in the form of convective or conductive heat, or converted IR or visible light energy.
I showed real-world examples of LED light energy being converted to heat, and of HPS convective heat being removed, leaving mainly IR.
Clearly the remaining IR did not have much of an adverse impact on my plants, so I would suggest it is somewhat overstated on your part.
The problem is, you always use selective information and never quantify it. Here is another graph, from the same source, which is somewhat different to yours.
I'll just remind everyone here that to read these graphs, the heights of the peaks are relative to the area under the curve, which tells you exactly how much of each spectral group is being emitted. In the case of IR (which incidentally starts at 700nm), as a percentage of the area under the curve, it is minor compared to the combined area of all other spectra.
Don't let people like wietefras try to baffle you with bullshit - real-world examples work in the real world.
And people who can't back their shit up usually run away . . .
Prawn Connery
Well-Known Member
Yes. He'll tell us all to go and read a book on how to be nice 