Light Quantity vs Light Quality Evidence ... Just for 4 u gg lol!

Stephenj37826 said:

Around 95+% of the light also turns into heat as well. Some is carried away as humidity from transperation. Almost all energy in ends up as heat in the end.

That being said if you can reach your desired light level with lower energy in then you have improved system efficiency.

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Read what this guy said, he's basically saying what i said, it's pretty much always 1000w = 1000w give or take a very small amount.

Yodaweed said:

yeah but it's not a huge factor, 1000w of hps will be just about as much heat as 1000w of mh lights,same with 1000w of leds, main difference will be leaf temps due to ir (which heats surface but won't create more watts or heat in the whole system) , if you don't believe me enclose a 1000w hps in an area, take temp measurements then enclose a 1000w metal halide, should be very close temp wise.

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I know it's not true. My 400 w super HPS runs noticably cooler than my 400 watt daylight MH.

the mh needs more cooling.

Yodaweed said:

That defies the laws of physics , mainly the first law of thermodynamics, 1000w of any source will nearly = 1000w of another in an enclosed system google first law of thermodynamics and read it. Light is radiant energy , which transfers to heat. All watts were created equally

http://www.rapidtables.com/convert/power/Watt_to_BTU.htm

For quick conversions to estimate how many BTU of Air Condition you will need.

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Well, since photosynthesis is endothermic and the energy is stored inside the plant.
The light that is being used for photosynthesis won't turn into heat.

But photosynth is at most 13% efficient https://www.researchgate.net/publication/229939005_The_maximum_efficiency_of_photosynthesis

The difference is really small though.
Even if you have a LED system that's literally 100% efficient, and a HPS that's 30% effficient. Both 1000 watt, it's a difference of less than 100 watt.
In reality the difference would be much closer to 30-40 watt.

So you're mostly right, 1000 watt LED box is going to be just about as hot as a 1000 watt HPS box.

MichiganMedGrower said:

I know it's not true. My 400 w super HPS runs noticably cooler than my 400 watt daylight MH.

the mh needs more cooling.

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That's odd cause usually HPS runs a bit warmer than MH , but it's usually not a huge difference.

frica said:

Well, since photosynthesis is endothermic and the energy is stored inside the plant.
The light that is being used for photosynthesis won't turn into heat.

But photosynth is at most 13% efficient https://www.researchgate.net/publication/229939005_The_maximum_efficiency_of_photosynthesis

The difference is really small though.
Even if you have a LED system that's literally 100% efficient, and a HPS that's 30% effficient. Both 1000 watt, it's a difference of less than 100 watt.
In reality the difference would be much closer to 30-40 watt.

So you're mostly right, 1000 watt LED box is going to be just about as hot as a 1000 watt HPS box.

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That's all i was saying, it's going to be very similar heat wise, might be a lil less for the LED's but like you said, it's almost always nearly even.

Yodaweed said:

That's odd cause usually HPS runs a bit warmer than MH , but it's usually not a huge difference.

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It's the same answer as the led. Efficiency. HPS is way more efficient than metal halide.

Now ceramic metal halide is a game changer here but only with the square wave ballast.

I don't know too much about led's yet but it seems that their heat vs. light output can be adjusted with components too. Thermal paste. Better drivers and heat sinks. Etc.

MH runs hotter watt for watt because less light output means more heat from the same wattage.

MichiganMedGrower said:

It's the same answer as the led. Efficiency. HPS is way more efficient than metal halide.

Now ceramic metal halide is a game changer here but only with the square wave ballast.

I don't know too much about led's yet but it seems that their heat vs. light output can be adjusted with components too. Thermal paste. Better drivers and heat sinks. Etc.

MH runs hotter watt for watt because less light output means more heat from the same wattage.

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None of what you said reduces heat, it just transfers it, energy cannot be created nor destroyed.

Yodaweed said:

None of what you said reduces heat, it just transfers it, energy cannot be created nor destroyed.

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So why are some sources hotter than others of the same wattage?

My little led flashlight lights up a huge area but I can touch the bulbs. The incandescent flashlight lights up way less area and the bulb is hot to touch. There are definitely variables here.

I am definitely not claiming to be a lighting expert. I really don't know the answer if what I wrote is not true.

MichiganMedGrower said:

I am pretty sure that the type of lighting changes this fact. You are talking about ignited gasses in a tube rather than a circuit only. They can produce different light to heat ratios.

Even HPS and MH have different heat to light amounts.

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Yes and also the extra amount of infrared light/heat that hps creates does not occur from cobs.so yeah maybe that make the same amount of heat but cob heat does not burn leaf as bad as hps heat and because most of it comes off the back of the cob its much easier to exhaust because it doesnt heat all the walls,plants,dirt ect that hps does.but yoda knows this,he just chooses to ignore certain facts and cherry pick the info he can use to troll lol.

frica said:

Well, since photosynthesis is endothermic and the energy is stored inside the plant.
The light that is being used for photosynthesis won't turn into heat.

But photosynth is at most 13% efficient https://www.researchgate.net/publication/229939005_The_maximum_efficiency_of_photosynthesis

The difference is really small though.
Even if you have a LED system that's literally 100% efficient, and a HPS that's 30% effficient. Both 1000 watt, it's a difference of less than 100 watt.
In reality the difference would be much closer to 30-40 watt.

So you're mostly right, 1000 watt LED box is going to be just about as hot as a 1000 watt HPS box.

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Agree with this

Also to add to this, HPS may actually be cooler than LED if a cool tube or sealed hood is used, as it allows quick evacuation of the dispersed heat where LED lets is into the grow space without immediate evacuation.

Also, the materials the grow area are made of my influence this too, as some materials reflect IR and Far red, others allow its transmission of the heat energy such as cinderblocks and bricks, vs pandafilm... a very minimal difference but could cause differences in the actual heat readings inside a grow area. (based on IR/Far Red emmission and amounts of light source)

Still generally speaking, equal wattage, equal heat load but the environmental variables may influence how this heat is absorbed, stored and transferred.

Yodaweed said:

None of what you said reduces heat, it just transfers it, energy cannot be created nor destroyed.

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Tell ya what
Go lay under a 100w uv lamp for an hour then under a 100w cree cbx 3590 and let us know which one burns yer ass quicker.i mean the cree should be just as bad because they are both 100w right smartass?

MichiganMedGrower said:

So why are some sources hotter than others of the same wattage?

My little led flashlight lights up a huge area but I can touch the bulbs. The incandescent flashlight lights up way less area and the bulb is hot to touch. There are definitely variables here.

I am definitely not claiming to be a lighting expert. I really don't know the answer if what I wrote is not true.

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The incandescent flashlight likely consumes a bit more power.
Also the efficiency determines what heat is being radiated, and ward stays in the bulb.

Also an example, if you have a 36 watt t5 you can touch it.
But a 36 watt incan will burn your hand.

The difference is the surface area.
On the T5 the heat is spread over a larger surface.

sixstring2112 said:

Tell ya what
Go lay under a 100w uv lamp for an hour then under a 100w cree cbx 3590 and let us know which one burns yer ass quicker.i mean the cree should be just as bad because they are both 100w right smartass?

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But a sunburn is damage from UV, not from heat.

frica said:

But a sunburn is damage from UV, not from heat.

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My point is all light is not created equal.the fact that uv affects skin and leaves,and ir light has an impact on how things below the lamp heat up

Someone mentioned cooltubes,they do very little to remove heat unless you run very short duct runs and use insulated flex pipe.the heat just radiates off all the ducting and stays in the room.i know,i have or had up to 20 cooltubes running here.

wietefras said:

@mauricem00, The McCree curve is not a light recipe. It merely demonstrates how efficiently the wavelengths are used for photosynthesis (using mono colored light of that wavelength in a grow chamber).

:edit: the absorptance spectrum is even less relevant.

Plants also perform perfectly fine on just the blue en red wavelengths used for chlorophyll. Of course you will then be limited to lower light intensities since you are only using chlorophyll and leave all all the other pigments without "work".

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plants clearly use this energy for something.as a gardener at the university once told me " I don't understand all these fancy theories. I need to let my plants tell me what they want".but I guess the LED crowd know more than the designer of plants. plants use light for a lot more than just photosynthesis. plant have close to 400 pigments that we have been able to identify and we are still learning what they do in plants.

frica said:

Yea vertical is great for HPS but maybe actually detrimental if you're using a directional lightsource.

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NO. Please stop speculating on things you haven't tried. If you want to know the truth, just ask.

wietefras said:

It doesn't. At best it shows that both quantity and quality have an effect. Which is obviously so. No one ever stated the opposite and that's never what the discussion was about.

The point is that what topicstarter claims is complete bullshit. He claims that:
- reducing the light quantity by almost half gives you the same yield
- with similar light intensity, HPS yields substantially less than LED

Both are complete nonsense and only demonstrate that his experiment was a complete bust.

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Like your BS claim of those plants in the other thread being bleached by the light, even though the leaves were perfectly fine... you really do talk some major crap

Clearly critical thinking and reading is beyond your mental capacity so I suggest you sit this one out

MeGaKiLlErMaN said:

Doesn't have to be you anyone will do that has grown that much with HPS, I've seen a few people get slightly over 1g/w but nothing near 1.6

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And that again just adds to the evidence that spectrum plays a major role, because that is the key difference between HPS and modern COB LEDs.

With HPS it was all about hitting 1g/w (strain dependent of course) but that was the magical target to try and aim for.

With LEDs its all about seeing if the boat can be pushed to 2g/w

GPW is something even the naysayers cannot dismiss although I am sure they will try

Edit I must confess after thinking about this that LEDs ability to convert a higher amount of electrical energy into useable light when compared to HIDs is probably the main reason for increased GPW figures although at this stage I am not discounting that spectrum could increase yields. But this does not account for variance in colour, taste and aroma nor how spectrum affects plant morphology, and how that in itself could affect overall yield. Maybe instead of arguing we should collectively put our heads together in order to create a set of experiments that can definitively answer these questions, any suggestions feel free to throw them out there folks!

Keep your 1 gpw HPS. Have fun buying and replacing those bulbs every year if you want to stay above 0.5 gpw.

Personally I'm going to stick with a 1.8 gpw system and I'll replace it when the efficiency is obsolete and people are hitting 2.5+ gpw. One thing you'll never see is a COB grower replacing one because it broke or died out.