Cooling BTU required for quantum boards inside a tent?

Indoor Growing Lighting
1

I am just curious how much BTU per HLG 550 quantum board I would need. It draws 480 watts from the wall but its a 1000w replacement apparently. So would I need the BTU to cool 480 watts or 1000 watts?

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another @dbrn32 this expert will see you right @learningthebasics

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Are you sure you need an air conditioner? If you do, watt to btu calculator is something like 350 btu/hour for 100 watts per hour. In which you would be concerned about actual watts dissipated. However I do believe there may be some square footage and other considerations you may need to make.

@Countryboyjvd1971 would you mind taking a look at this please?

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4

I think if I go with a 9x9 tent and do 4 lights in it I might be able to get away with just cooling down the room. But I think if I go the other route and put 7 lights in like a 8x16 I would need an AC in it.

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I was originally going to do 2 10x10 tents or one 10x20 but a 10x20 wont fit, and all the 10x10s are out of stock for over a month.

So its 9x9s and 8x16s for my options. Honestly at this point I am thinking of just doing a 12x8 in the master bedroom with a minisplit AC and then doing a 9x9 tent.

6

For the HLG 550 V2
From this lab testing sheet :

Input Power (W) = 472.90
Total Radiant Flux(W) = 243.13
Thermal Flux(W) = Input Power - Total Radiant Flux
= 472.90 - 243.13
= 229.77 watts as heat
For every hour of operation 229.77 Watt-hours = 784 BTU

For a 9x 9 tent x 7 feet (?) tall total surface area of four sides and roof is 9x9 + 4x(9x7) = 333 sq feet of heat transfer area ( floor not included for heat transfer)

Modeling the Grow Tentt wall material as
double bubble reflective radiant barrier
with an R value of 3.7

Temperature Delta = (R value x Heat Transferred)
--------------------------
Square Feet

Temp Delta = (3.7 x 784)/333
=8.7 (Deg F)

So, to keep Internal Grow Tent temperature at 76 F.

A/C External Room Temp = 76 - 8.7 = 67.2 F

This treats the tent as not exchanging air with the A/C room.

Venting air exchange acts as a drafty window… and drops the effective R value… requiring less Temperature Delta.

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I haven’t had a chance to welcome you to the forum @HammerOfLight. Welcome :wink::v::bear:

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Well … that was for one light.
For four lights in the same tent it is 3136 BTU

Temperature Delta = 3.7*3136/333 = 34.8 degrees F

A/C External room = 76 -34.8
= 41.2 F
again …considering no ventilation between tent and A/C room.

9

Thanks :+1::v:

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10

Thanks for the info! I was told that each HLG 550 v2 produces 1850, but it looks like according to your math its only about half of that! So I am still not sure if it is better to put the ac inside the tent or if I could get away with one outside the tent. Does that mean with 4 lights inside the tent it will raise the tents temp by 34.8 or no?

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Yes, that is what the math says.
In retrospect, I may have over-estimated the Rvalue of the tent wall at 3.7. Probably a more realistic value is ~1 to 1.2 so the temperature deltas would be about 1/3 of what I calculated above. Remember these calculations are based on not venting the tent, which you will need to do to get CO2 to your plants. So the temperature delta will be less when you vent the tent.

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Well with that little heat it doesnt look like I would need a mini split

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See this link to get a real world estimateof heat buildup in the tent with an exhaust fan.
The 5x5 tent used is about 40% the surface area of the 9x9 with 1 light slightly more power output than the hlg 550, looks like same qb288"s with a bigger driver.

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Hlg has btu calculator, like 1690 per fixture I believe

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15

Thanks for the link.
I didn’t realize that much light energy was ‘wasted’.
That makes my winter grow room more palatable.

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