PPFD - What sort of performance for this setup and space?

Vescovi

Vescovi

Active Member
Hi guys, I am making a lamp for a friend. Can you give an Idea of PPFD for his space?
His space Is 3.5 feet X 3.5 feet (One square meter).

8X CXB 3590 3500
4X MW 120H C1050 mA
4X 7x20 inch. heatsinks

I will evenly space the LEDS in a 24x24 inch array.
Obviously running just two LEDS per Driver.

What sort of performance are we looking at? Meaning PPFD.

Thanks in advance...
 
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SupraSPL

SupraSPL

Well-Known Member
3.27' X 3.27' (1m²)
75.5W X 8 = 604 Dissipation W
604 * 49.7% efficiency = 300 PAR W
300 * .9 reflector/lens/wall losses = 270 PAR W
270/10.7 = 25.23 PAR W/ft²
25.23 * 4.65 umol/s * 10.7 = 1256 PPFD

3.5' X 3.5'
75.5W X 8 = 604 Dissipation W
604 * 49.7% efficiency = 300 PAR W
300 * .9 reflector/lens/wall losses = 270 PAR W
270/12.25 = 22 PAR W/f²
22 * 4.65 umol/s * 10.7 = 1095 PPFD

Very high intensity, maybe too high in the hot spots? I have not tested above 1000 PPFD with COBs.
 
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salmonetin

salmonetin

Well-Known Member
....now i understand better the 10,7 value... 3.25' X 3.25' (1m²)

...but 3.25 * 3.25 = 10,5625 .... 10,6 to my eye... but im too bad on maths.. i accept 10,7 value ;)

pd...thanks again Supra...;)

:peace:

Saludos
 
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Vescovi

Vescovi

Active Member
Can anybody tell me wire gauges I should buy in millimetres?

Just curious to see if I understand it… If I had 300W 4 CXB3590s @ 1050ma in half that space, I would get the same number or half of the ppfd above?

Im just trying to get my head around it. @SupraSPL
 
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salmonetin

salmonetin

Well-Known Member
...for wires i think 1,0 mm or 1,5 mm are ok...

...try to do your own maths calcs... maybe then you understand better... a bit of practice on math calcs helps too...

...for this space 3.5' X 3.5'.... for these power 604 Dissipation W ...or...270 PAR W... you obtain... 22 PAR W / f²

....22 PAR W / f² are 1095 umols / m2 * sec or PPFD

3.5' X 3.5'
75.5 W (Vf * If) X 8 (cobs) = 604 Dissipation W
604 * 49.7 % efficiency = 300 PAR W
300 * .9 reflector / lens / wall losses = 270 PAR W
270 / 12.25 (3.5' X 3.5') = 22 PAR W / f²
22 * 4.65 umol/s * 10.7 = 1095 PPFD

...if you change the dissipation watts .. or efficiency or grow area the final numbers change too...

...prectice with diferent situations... diferent dissipation wats ...diferent efficiency... ...diferent area...;)

...maybe a good question its...
...how add the drivers and fans numbers here... but... first you must understand the math with only the leds... for the rest explications with drivers and fans go with Supra answers... or maybe you catch the idea and see yourself the solution...

:peace:

saludos
 
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Vescovi

Vescovi

Active Member
Let me see if I got this... In a space with 3x2 feet: 4x cxb3590 @ 1050 mA:

3X2 feet 6sqft
75.5W X 4 = 302 Dissipation W
302 * 49.7% efficiency = 150 PAR W
150 * .9 reflector/lens/wall losses = 135 PAR W
135/6 = 22.5 PAR W/ft²
22.5 * 4.65 umol/s * 10.7 = 1119 PPFD In a 3x2 Feet.

I want to understand the 10,7 number: 22.5 * 4.65 umol/s * 10.7

Is that correct? @salmonetin @SupraSPL

Sorry for the inconvenience once again... Just trying to get it right.
 
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salmonetin

salmonetin

Well-Known Member
4 cxb3590 @ 1050 mA ...In a space with 3 x 2 feet...

3 x 2 feet = 6 sqft
Vf @ 50ºC @ 1050 mA = 71,94 V x If @ 1050 mA = 75.5 W x 4 (cobs) = 302 Dissipation W
302 Dissipation W * 49.7% efficiency (for 5000ºK at 1050 mA) = 150 PAR W
150 PAR W * .9 reflector / lens / wall losses = 135 PAR W
135 PAR W / 6 (3 x 2 feet) = 22.5 PAR W / ft²
22.5 PAR W / ft² * 4.65 umol/s * 10.7 (10.764 sqft = ~1 m^2) = 1119 umols / m2 * sec ...or PPFD

...In a 3 x 2 Feet.... yes...

...302 dissipation w - 150 par w = 252 Heat W... ;)

...for my pov ...your calcs numbers are correct...;)

pd...(i edit conversion sqfeet to sqmeter) for better understanding of 10,7 value ...thank alesh...;)

:peace:

Saludos
 
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alesh

alesh

Well-Known Member
Vescovi said:
Let me see if I got this... In a space with 3x2 feet: 4x cxb3590 @ 1050 mA:

3X2 feet 6sqft
75.5W X 4 = 302 Dissipation W
302 * 49.7% efficiency = 150 PAR W
150 * .9 reflector/lens/wall losses = 135 PAR W
135/6 = 22.5 PAR W/ft²
22.5 * 4.65 umol/s * 10.7 = 1119 PPFD In a 3x2 Feet.

I want to understand the 10,7 number: 22.5 * 4.65 umol/s * 10.7

Is that correct? @salmonetin @SupraSPL

Sorry for the inconvenience once again... Just trying to get it right.
Click to expand...
Conversion from sqft to m^2.
1 m^2 = ~10.764 sqft
 
ya bongo

ya bongo

Well-Known Member
my short math

starting with the Cree PCT tool
pct-3590.jpg
4X CXA3590/ 72V/ 1.05A - Tj=50°C


P=79.67W
Eff.= 104.5lm/W
LER=~320lm/W

eff: 104.5/320=0.327
Prad: 79.667*0.327=26.02W
PPF: 4*26.02*4.65=484µmol/s

and for PPFD I need Distance, Beamangle and Spread of the Cobs.
 
salmonetin

salmonetin

Well-Known Member
...:hug:...ese ya bongoooo...:lol::lol::lol: ;)

...i never tried the pct tool... lazy pc and inet connection...:wall: ...thanks a lot for your post...:idea:

pd... other great mental seed ehhh... guod style...:hump:... short math? ehhh nahhh...not for my pov... ;)

Saludos
 
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Greengenes707

Greengenes707

Well-Known Member
The pct tool and the data sheets are very conflicting. They were like this with the CXA too. But single dies like xte's and xbd's are represented correctly. It has baffled me for a while and no one has come up with a definitive answer.

Example...
Put an cxb in there and put a xbd in the other...
Then set it to 85c(what they are binned at)
And compare to the data sheet nominal data.

The cobs will be significantly lower than minimum figures...basically a whole bin low.
While the single dies will be dead on the correct bin output.
 
Vescovi

Vescovi

Active Member
Greengenes707 said:
It's a nice little figure to remember so you don't have to calculate out the area in m2 for every separate sqft situation.
Click to expand...
But my math is correct @Greengenes707?

4x cxb 3590 @1050mA
3X2 feet 6sqft
75.5W X 4 = 302 Dissipation W
302 * 49.7% efficiency = 150 PAR W
150 * .9 reflector/lens/wall losses = 135 PAR W
135/6 = 22.5 PAR W/ft²
22.5 * 4.65 umol/s * 10.7 = 1119 PPFD In a 3x2 Feet.
 
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