Heat from 1200W of 1212's/vero 29's/cxm-22/cxb3590 compared to 2x 600W?

I am wondering if anybody can comment on this from experience within your own grow rooms.

Roughly what percentage of heat in comparision to HPS would these LEDS give out when driven at 50w per cob?

I am assuming from reading that they run less hot, but would hoping for half the heat as a HPS of equivilant wattage be hoping for too much?

If your experience is from previous generation chips, please mention that too...

Thanks

in a room 1200W of anything is 1200W

will produce the same amount of heat

cobs will give you more usable light for that same 1200W, or an equal amount of light for a lesser wattage, like 800W

I think he is asking about the excess waste heat that is left over from what the plants don't use for photosynthesis.

There are a number of factors involved. Air circulation, distance to canopy, you know the drill. There isn't a like for like comparison. One person could over drive a few cobs to use 1200w and have a massive heat problem whereas another can use 60 cobs at 20w each producing no significant heat.

What I do like about LEDs is the heat reduction and the ability to get more PAR at the canopy without the crazy heat. As long as the temp stays in the 20-30degree range, the plants will handle 2k+ ppfd. I think light bleaching doesn't exist and is confused as heat stress.

CobKits said:

in a room 1200W of anything is 1200W
will produce the same amount of heat
cobs will give you more usable light for that same 1200W, or an equal amount of light for a lesser wattage, like 800W

Click to expand...

From my understanding, I thought that if 1200W was used at say 65% correctly(light) (35% loss translating to heat) then technically the unwanted waste heat comes from 35% of the 1200Watts?

Also if cobs give you more useable light for the same 1200W, that kind of implies that it cant produce the same amount of heat... - if my understanding is correct that is...

Raging Stalk said:

One person could over drive a few cobs to use 1200w and have a massive heat problem whereas another can use 60 cobs at 20w each producing no significant heat.

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This was my point, the fact of applying 1200w differently must translate to a different level of heat. not 1200w = 1200w

I guess il wait for more comments

Joe34 said:

From my understanding, I thought that if 1200W was used at say 65% correctly(light) (35% loss translating to heat) then technically the heat comes from 35% of the 1200Watts?

Also if cobs give you more useable light for the same 1200W, that kind of implies that it cant produce the same amount of heat...

Click to expand...

Yup, But even the light it makes turns back into heat. Heat on the surfaces it hits and heat from the plant processing it.

majins said:

Yup, But even the light it makes turns back into heat. Heat on the surfaces it hits and heat from the plant processing it.

Click to expand...

So then it becomes an issue of how much heat is created from light, and how much from loss wattage.

As LED useually outputs more light, I assume it will be less heat.

Putting the science aside.
If anybody has/is running e.g 600w in LEDS, is your room a lower temp than it would be with a HPS or the same temp?

you will need to exhaust or cool the room. The heat will just build upon itself otherwise, not yo mention humidity.

Joe34 said:

From my understanding, I thought that if 1200W was used at say correctly(light) (35% loss translating to heat) then technically the unwated waste heat comes from 35% of the 1200Watts?

Also if cobs give you more useable light for the same 1200W, that kind of implies that it cant produce the same amount of heat... - if my understanding is correct that is...


This was my point, the fact of applying 1200w differently must translate to a different level of heat. not 1200w = 1200w

I guess il wait for more comments

Click to expand...

I think what you're talking about is efficacy-how efficient is the lamp at converting electrical energy into light and heat. You need to find out the efficacy of the arrays you want to compare-that will tell you the percentage of power that is converted to PAR energy and the remainder is dissipated as heat.

Yes gbauto thats would be underlying issue.

However im just after a general answer from the average COB LED setup these days - Would a 600w @ 50w per cob grow room run as hot as running a 600w bulb, I assume it wont but maybe im wrong.

I will have my own setup soon, so I will find out one way or another, but it would be nice to get some rough expectations.

Shouldn't be even close with 12 cobs.

Joe34 said:

Yes gbauto thats would be underlying issue.

However im just after a general answer from the average COB LED setup these days - Would a 600w @ 50w per cob grow room run as hot as running a 600w bulb, I assume it wont but maybe im wrong.

I will have my own setup soon, so I will find out one way or another, but it would be nice to get some rough expectations.

Click to expand...

A 600w HPS is about a third as efficient in light vs heat generation as an led. Example 600w hps will generate 400w of heat for 600w light while an led will produce 200w of heat for 600w of light

@VegasWinner Thats along the lines I was thinking.

Cheers!

I did put more power into fans for the entire room mainly because I had the space on the same circuit breaker. 20" box fans move a lot more air using 54w on the #1 setting (84w on 3) than a bank of 12v PC fans. Every leaf shall move.

My total power for fans is about 18% and I think very well worth the investment.

Joe34 said:

Yes gbauto thats would be underlying issue.

However im just after a general answer from the average COB LED setup these days - Would a 600w @ 50w per cob grow room run as hot as running a 600w bulb, I assume it wont but maybe im wrong.

I will have my own setup soon, so I will find out one way or another, but it would be nice to get some rough expectations.

Click to expand...

I would suspect that there are spec charts for the type of bulb(MH, HPS)-another concern is the amount of IR that the bulb produces. It's a simple equation for determining the energy loss through heat if you know the efficacy of the emitter.

GBAUTO said:

I would suspect that there are spec charts for the type of bulb(MH, HPS)-another concern is the amount of IR that the bulb produces. It's a simple equation for determining the energy loss through heat if you know the efficacy of the emitter.

Click to expand...

Or we could try it the other way and determine the amount of radiant heat generated by the cob at specific power. That might be more accurate than the SPD charts provided by some vendors that look like they were drawn with crayons.

I'll look into the math on it this week. A simple set up just needs to measure the increase in water temperature for a fixed volume above ambient. Sure it won't be exact but +/- 5% accuracy or better is probably as good or better than we have now.

Quick look up - it is specific heat. Will dig deeper.

Joe34 said:

I am wondering if anybody can comment on this from experience within your own grow rooms.

Roughly what percentage of heat in comparision to HPS would these LEDS give out when driven at 50w per cob?

I am assuming from reading that they run less hot, but would hoping for half the heat as a HPS of equivilant wattage be hoping for too much?

If your experience is from previous generation chips, please mention that too...

Thanks

Click to expand...

You have 2 different heat types when dealing with HID vs LED...... That said the same wattage in LED will produce the same heat but you will more easily manage the LED side as the waste heat is directly transmitted to the air as with HID the waste heat will be in the form of Infrared hear which will soak everything the light touches with additional heat...... So to answer what you are asking it will be easier to manage the LED side especially since you want to run 5+° warmer with LED to achieve optimal leaf surface temperatures vs HID.

Joe34 said:

So then it becomes an issue of how much heat is created from light, and how much from loss wattage.

As LED useually outputs more light, I assume it will be less heat.

Putting the science aside.
If anybody has/is running e.g 600w in LEDS, is your room a lower temp than it would be with a HPS or the same temp?

Click to expand...

Yes, good LEDs put out more light.

That light eventually also turns into heat..
Photosynthesis while endothermic is very inefficient so negligible.


Energy that's stored inside the plant doesn't turn into heat (only a very tiny amount).
So 1200W of LED practically produces just as much heat as 1200W of HPS.

But the radiation of the 2 sources is different.
HPS has some IR which will radiate right on your plants and you can assume all of that will turn into heat the moment it hits your plant.
So even if room temp is equal, plants under HPS will have warmer leaves because of the IR radiating on the leaves. Something to consider.

Even funnier if you're trying to grow with incandescent, should be very hard since incandescent bulbs are extremely efficient IR producers and will easily fry your plants even if ambient temperature isn't very high.

Joe34 said:

Yes gbauto thats would be underlying issue.

However im just after a general answer from the average COB LED setup these days - Would a 600w @ 50w per cob grow room run as hot as running a 600w bulb, I assume it wont but maybe im wrong.

I will have my own setup soon, so I will find out one way or another, but it would be nice to get some rough expectations.

Click to expand...

yes exactly as hot on an overall basis

the cobs will put out more light for the same 600W

I thought heat generation was tied to efficiency, more efficient, less heat?

CobKits said:

in a room 1200W of anything is 1200W

will produce the same amount of heat

cobs will give you more usable light for that same 1200W, or an equal amount of light for a lesser wattage, like 800W

Click to expand...

pop22 said:

I thought heat generation was tied to efficiency, more efficient, less heat?

Click to expand...

Because the light will also turn into heat eventually, and since that light stays in your room it becomes heat in your room.

Photosynthesis stores some energy inside the plant (doesn't become heat), but photosynthesis is rather inefficienct so you can safely ignore it.
So 1200W will always be 1200W.