What would you recommend to replace a 1000w HPS in a 4x4 tent?

[Yodaweed]

Light and infrared radiation are electromagnetic waves but they operate at different wavelengths/frequencies and effect matter differently at the atomic level.

If your light emits a wide EM band like HPS some of your energy is realized as infrared or non utilized wavelengths and thus the less efficient mechanism for producing visible light because your wasting some energy emitting wavelengths that aren't seen or utilized only transformed into heat.

LEDs emit a narrow EM band and so less energy is used for non utilized wavelengths (if you purchase the correct color temp), including infrared. This helps increase the efficiency of the mechanism when concerning the production of visible light.

When talking about a tent or the temperature of a system I'm not convinced that the majority of heat observed is from visible light interacting with water filled plant matter. In fact I'm almost certain it accounts minimally in overall temp realization compared to that of the heat of the emitting source (filament, LED) or power supply electronics.

The question is, how much of visible or utilized light is converted into heat, and I don't know enough to say.

If its true that only 1-3% of the light is absorbed by the plant then that means only 1-3% is transformed into heat. I know there are many different factors that go into a systems temperature (a tent), including EM spectrum, ballast location, hood vents & air circulation, material, strain, ect, so I have a hard time accepting someone saying something like all light eventually gets converted into heat or that its even a big enough of a phenomenon to test out, as I stated earlier Im confident the majority of heat is from other sources. But if you have anectdotal evidence and have noticed it's a big part of your heat battle then fair enough. Ill take your word for it.

 

[Rahz]

If its true that only 1-3% of the light is absorbed by the plant then that means only 1-3% is transformed into heat.

What you're missing here is that any light not absorbed by the plants is converted to heat. For instance

100w lamp is 50% efficient.
50w of waste heat.
50w of light.
Plant absorbs 3w of light
47w of light converted to heat.
Total of 97w of heat.

 

[Yodaweed]

What you're missing here is that any light not absorbed by the plants is converted to heat. For instance

100w lamp is 50% efficient.
50w of waste heat.
50w of light.
Plant absorbs 3w of light
47w of light converted to heat.
Total of 97w of heat.

 

[JSheeze]

2 enclosed circulated tents, 1 gets a 1k HPS shined onto a green board, 1 gets a 1k COB shined onto a green board, lol lmk what the the temps read after a few hours, if they the same ill eat my words...

Idk where you guys get this "law" that "all light is converted into heat" from??? The only way you could see your plants is because the light is reflected, that goes for anything you look at. So if all light is converted into heat then you shouldn't be able to see anything...

I do get that the surroundings absorb some light energy and transfer that into vibrational energy or heat, but not all of it, not even close, and it would depend on the surroundings properties, color, reflectiveness ect, which is designed to be minimalized with Mylar and/or white surfaces. Take for example a black shed vs a white shed on a sunny day, black will convert more EM radiation into heat where as the white shed will reflect and be much cooler.

The LED and HPS emit heat at the source differently. The HPS emits IR when turned on, the LED has visible light transformed into IR later (but at what rate?? Many many factors...), also right along side with the HPS' visible light (all light).

Tents are cooled by removing air that has increased in temp. Ie convection. If you're emitting IR you're going to have more convection due to increased radiant energy to the surfaces it bombards.
Cooling the tent then deals with cooling the light and any surfaces heated by IR, all by exchanging the air fast enough in the tent to create a greater temp difference between the 2 (surface and pumped in air) thus averaging the 2 to a lower overall temp.

If you're not emitting IR the surfaces that the light touches in your tent will be cooler comparatively and you will have less radiant energy being observed as convection and thus the the amount of venting to remove the smaller convection heat will also be smaller.

If all light turns into heat why don't we use fluorescents to heat up our food instead of IR bulbs to keep them warm? A 10w IR spectrum heavy bulb will put off more radiant heat than a 10w 5500k led.. Seems like the food and reptile industry is really overpaying for those specialized IR bulbs when they could just buy LEDs...

Put a glass of water under an IR bulb for an hour, do the same with an white LED, temps of the water under IR are going to be higher, because water absorbs IR, LED doesn't emit very much IR , plants are basically water, heat your plants up with IR well then now you have 2 sources of heat to worry about increasing tent temps... Some LED light will be coververted into IR too but HPS already emits IR and that's the difference.. Both the HPS and LED are going to have some visible be coverted into IR , but HPS has it before it has to covert anything as well as alongside the visible that will be coverted, a double whammy..

 

[Prawn Connery]

Light isn't converted into heat - light is heat. All electromagnetic radiation is heat (thermal radiation). "Heat" is simply the transfer of energy: be it conductive, convective or electromagnetic.

What you are talking about is thermal absorption - the rate at which energy from various wavelengths is absorbed, reflected or refracted by various molecules.

In a completely closed environment, all energy is emitted and absorbed until a state of equilibium is reached. Even two mirrors facing each other will eventually absorb photons of light shone on them - and their temperatures will correspondingly increase.

So you are correct that infrared radiation is more readily absorbed by water and other molecules, and that light outside the PAR range is not converted to work or latent energy by plants (except in the case of convective energy transfer in the form of transpiration).

But . . . all that light is still heat. That is if you are using the correct definition of the term "heat", and not confusing it with "temperature" . . .

 

[Yodaweed]

Light isn't converted into heat - light is heat. All electromagnetic radiation is heat (thermal radiation). "Heat" is simply the transfer of energy: be it conductive, convective or electromagnetic.

What you are talking about is thermal absorption - the rate at which energy from various wavelengths is absorbed, reflected or refracted by various molecules.

In a completely closed environment, all energy is emitted and absorbed until a state of equilibium is reached. Even two mirrors facing each other will eventually absorb photons of light shone on them - and their temperatures will correspondingly increase.

So you are correct that infrared radiation is more readily absorbed by water and other molecules, and that light outside the PAR range is not converted to work or latent energy by plants (except in the case of convective energy transfer in the form of transpiration).

But . . . all that light is still heat. That is if you are using the correct definition of the term "heat", and not confusing it with "temperature" . . .

 

[wietefras]

Light isn't converted into heat - light is heat. All electromagnetic radiation is heat (thermal radiation). "Heat" is simply the transfer of energy: be it conductive, convective or electromagnetic.

That is an incorrect attempt at an oversimplification.

Light is NOT heat.

You are confusing the transfer of heat with different forms of energy.

 

[JSheeze]

Light is when photons of electromagnetic energy are released from electrons dropping from excited states into lower levels.

FF to 2:18...
https://www.khanacademy.org/science/physics/quantum-physics/atoms-and-electrons/v/atomic-energy-levels

The amount of thermal radiation produced by visible light is variable mainly depending on what the light is shining on.
If the visible light is absorbed, in the case of something painted black (does not reflect light back) then much of the visible light is transformed into thermal radiation. We observe this as the surface of the black object increases in temperature relative to its surroundings.

If the visible light is reflected then there is no electron interaction and so the body that's reflected stays the same temp and is also easy to see from the fact the light is reflecting off the object.

Watts of an LED are the unit of power used to produce photons. If more watts are used to make photons than emit thermal radiation then you will have less "heat"/thermal radiation/IR per watt used. This is described as efficiency.

Because LEDs are more effecient than HPS, more power of LEDs go into producing photons/watt than that of HPS. Vice versa, less power or watts of LEDs go into producing IR than HPS, respectively.

Because the tents are reflective the majority of absorption is in the plants, and everyone here seems to say that's only at 1-3%. So when you open your tent and its blinding, that's because the majority of your visible light wasn't converted into IR or "heat" but reflected... Lol

Your heat issues in your tent are from your EM spect, and the operating temp of any tech inside. LED is way cooler operating on a heat sink then HPS of same wattage. The tent is not an absolute barrier so the small thermal disipations from a passively cooled LED are easily absorbed by the tent into the surrounding room and house at a rate that doesn't effect much of the internal temp.

Visible light is NOT heat.

 

[Yodaweed]

Light is when photons of electromagnetic energy are released from electrons dropping from excited states into lower levels.

FF to 2:18...
https://www.khanacademy.org/science/physics/quantum-physics/atoms-and-electrons/v/atomic-energy-levels

The amount of thermal radiation produced by visible light is variable mainly depending on what the light is shining on.
If the visible light is absorbed, in the case of something painted black (does not reflect light back) then much of the visible light is transformed into thermal radiation. We observe this as the surface of the black object increases in temperature relative to its surroundings.

If the visible light is reflected then there is no electron interaction and so the body that's reflected stays the same temp and is also easy to see from the fact the light is reflecting off the object.

Watts of an LED are the unit of power used to produce photons. If more watts are used to make photons than emit thermal radiation then you will have less "heat"/thermal radiation/IR per watt used. This is described as efficiency.

Because LEDs are more effecient than HPS, more power of LEDs go into producing photons/watt than that of HPS. Vice versa, less power or watts of LEDs go into producing IR than HPS, respectively.

Because the tents are reflective the majority of absorption is in the plants, and everyone here seems to say that's only at 1-3%. So when you open your tent and its blinding, that's because the majority of your visible light wasn't converted into IR or "heat" but reflected... Lol

Your heat issues in your tent are from your EM spect, and the operating temp of any tech inside. LED is way cooler operating on a heat sink then HPS of same wattage. The tent is not an absolute barrier so the small thermal disipations from a passively cooled LED are easily absorbed by the tent into the surrounding room and house at a rate that doesn't effect much of the internal temp.

Visible light is NOT heat.

 

[JSheeze]

Here, have a convo with yourself lol...

all light sources produce the same amount of heat only thing that matters is the watts that's being used

the only thing that matters is how many joules of energy (watts are a measurement of joules over time) was used, 1000w is 1000w (which both are 1000 joules / second)

all energy eventually turns in heat.....and the amount of absorption is extremely inefficient (1-3% of light)so it can safely be ignored....1000w hps = 1000w led.

If you think a light that's 10% effiecent makes 90% heat you are completely ass backwards, 100% of all light turns to heat.

E=mc^2 is not about that's it's about the increased relative mass of a body times the speed of light squared....it has nothing at all to do with grow lights....i really advise you going and picking up a good book on physics you really do not know what you are talking about.

 

[Prawn Connery]

That is an incorrect attempt at an oversimplification.

Light is NOT heat.

You are confusing the transfer of heat with different forms of energy.

Energy is energy. The absorption of any electromagnetic radiation (light) produces heat - which is simply the translational kinetic energy of an atom or molecule (thermal energy). It is the properties of the interaction of photons with electrons that determine how much their energy state is raised or lowered. But in a closed system, you cannot have electromagnetic radiation without heat (or vice versa).

"Oversimplifications", by definition, are never going to be entirely accurate. But that does not mean they are "incorrect". Unless you subscribed to the theory that all knowledge is in a state of flux, so nothing is strictly "correct".

Because the tents are reflective the majority of absorption is in the plants, and everyone here seems to say that's only at 1-3%. So when you open your tent and its blinding, that's because the majority of your visible light wasn't converted into IR or "heat" but reflected... Lol

That's all good and well, but if the LED keeps pumping photons into the tent, what happens to them?

Are you saying that if you kept the tent closed for 10 years, when you opened it, 10 years worth of photons would suddenly jump out?

You know that doesn't happen. So have a think about it: what happens to all those photons? Eventually, they all must be absorbed, correct? There is no such thing as a 100% reflective surface - and certainly not inside a grow tent!

That energy has to go somewhere, does it not? And if it has to go somewhere, where does it go? It doesn't just "disappear" . . .

Visible light is NOT heat.

In the same way IR is not heat. But they both transfer the same energy that causes heat.

 

[lukio]

Here, have a convo with yourself lol...

yodaweed pretending he knows shit. lololololololol

 

[JSheeze]

Energy is energy. The absorption of any electromagnetic radiation (light) produces heat - which is simply the translational kinetic energy of an atom or molecule (thermal energy). It is the properties of the interaction of photons with electrons that determine how much their energy state is raised or lowered. But in a closed system, you cannot have electromagnetic radiation without heat (or vice versa).

"Oversimplifications", by definition, are never going to be entirely accurate. But that does not mean they are "incorrect". Unless you subscribed to the theory that all knowledge is in a state of flux, so nothing is strictly "correct".


That's all good and well, but if the LED keeps pumping photons into the tent, what happens to them?

Are you saying that if you kept the tent closed for 10 years, when you opened it, 10 years worth of photons would suddenly jump out?

You know that doesn't happen. So have a think about it: what happens to all those photons? Eventually, they all must be absorbed, correct? There is no such thing as a 100% reflective surface - and certainly not inside a grow tent!

That energy has to go somewhere, does it not? And if it has to go somewhere, where does it go? It doesn't just "disappear" . . .


In the same way IR is not heat. But they both transfer the same energy that causes heat.

Yep, I pretty much agree.

Like I've said already, some of the visible light interacts but it depends on many different factors.


Also like I've said the tent is not a closed system. The walls are not absolute barriers.


The "heat" folks are having to treat is the IR emitted by different lights and the thermal radiation produced by power supplies and tech. Not the fractional amount of visible light converted into thermal over time.


In a closed system all light can be transformed (Kinetic, Thermal, Electrical), but if the system is closed it's always in equlibrium. Meaning there's no power fluctuation or work being done on an outside body, just energy transformation within... but grow tents aren't closed systems and the rate that visible light is coverted is minimal over time (folks seem to be saying 1-3% but who knows and at what rate), whereas the tech and IR increase the thermal gradient much quicker compared to the visible light.


The way HPS are designed, they put off more thermal radiation than LED. Aside from some visible light being absorbed by both types of light the HPS converts less power to photon production than LED and more power to thermal radiation than LED. IR is more readily absorbed by water than visible. Because the tent walls aren't absolute barriers the rate at which photons are absorbed by different wavelengths matters.


So arbitrarily a 1000w of HPS that's 45% efficiect produces 55% into thermal which is more readily absorbed. And let's say the LED is 60% efficient, then 40% is thermal. A 150w difference.


Just do the expirement. 1k hps vs 1k led. Also one of biggest factors is the cooling tech, way better on LEDs. Big heat sinks that HPS don't have... rates matter...


Appreciate the sensible reply though.

yodaweed pretending he knows shit. lololololololol

Lol I'm giving this subject a rest, I knew I shouldn't have ...

 

[wietefras]

The absorption of any electromagnetic radiation (light) produces heat

Exactly and your earlier claim that "Light isn't converted into heat" is simply wrong.

Just do the expirement. 1k hps vs 1k led.

In that case the difference between HPS and led has nothing to do with efficiency. Both 1k of led and 1k of HPS will produce 1k of heat (minus a tiny bit of biomass).

The point is:
- You would use say 750W of led vs 1000W HPS. That's where the lower cooling requirements comes from.
- Plus that HPS generates more radiated heat while led produces more convection heat which simply rises away from the plants and is easier to extract.

You guys are really just making things worse and less clear. Just stop trying to explain/simplify stuff you don't really understand yourself.

 

[Prawn Connery]

- Plus that HPS generates more radiated heat

LOL! And after all that, you use a term like "radiated heat". And don't even qualify/quantify it.

What is "radiated heat"? And why does a HPS "generate more" than an LED?

while led produces more convection heat which simply rises away from the plants and is easier to extract.

That assumes the HPS isn't in a cool tube, which would arguably duct away more convective heat than an LED attached to a heat sink. A lot of assumptions in that statement. A heat source only "produces" as much convective heat as convection will allow.

Just stop trying to explain/simplify stuff you don't really understand yourself.

I will if you will

 

[wietefras]

LOL! And after all that, you use a term like "radiated heat". And don't even qualify/quantify it.

What is "radiated heat"? And why does a HPS "generate more" than an LED?

The fact that you don't even know the answers to those basic questions says it all really.

Just knock it off with the pretentious nonsense.

 

[hybridway2]

Lol! 1000w of 1.3 umol/j HPS w/ mad IR runs much cooler then 1000w led 2.0 Umol/j +. When in a vented hood. Plus HPS is a remote ballast whereas most led comp unfortunately are still piggybacking heat box drivers ontop of hot plate heatsinks & LEDs. It's crazy that almost 50% added heat to your growroom is Simply not an issue to you guys who fight over a .04% possible efficiency difference. LEDs dont need to be vented, you just need to get the drivers out of the room.
Vented HPS w/ a ballast outside of the room @ a low efficiency rating & light losses is believe it or not equalling the efficiency of your new tech led for your room as a whole if your fighting that unnecessary heat. Granted much of this mostly pertaining to Co2 growers in a sealed room like myself but that doesn't change the facts.
Yodas right BTW! LOL!

 

[wietefras]

So you hang a 1000W light and then you are worried about the tiny bit of heat from say 50W dissipated by the driver?

 

[WeedSexWeightsShakes]

Fact:
My LED’s make no heat, only light.

 

[NanoGadget]

I have QBs and mounted my drivers outside my grow space when i first got them, and i actually ended up putting them back on top of the slate because my space actually got cooler than i wanted. whereas mounting the ballasts for my HPS external from my space made very little difference as most of what was heating up the space was coming from the bulb, not the ballast.