CO2 fixation calculation tool for COBs

Well...
I'm not able to go to sleep ,tonight ...
So -just for the fun of it- made a new tool ...

A spreadsheet that calculates how many grams of CO2 your plant(s) fix per light cycle .

How it works :

Basically it multiplies the RQE McCree curve with the Cannabis L. Sativa absorptance spectrum.
The result is ,what I like to call " Photosynthetic Potentional " ak PP .
Then the spreadsheet multiplies PP with the light source's umol/nm (at a given power ).

The result is how many of these photons are used to fix carbon molecules per light cycle ...

As an example I've used the Cree CXB 3590 3000°K 80Ra 36V type,bin CB .
Driven at 1400 mA ( 1.4 A )

Assuming that all the emitted photons are being incident to leaf canopy ....
Then this particular COB has an PP efficiency of 74.12 % ( meaning that from all the photons emitted ,
that percentage is actually being used for carbon fixation ) and during the 12 hour light course ,
16.1 grams of CO2 are being fixed ( per single COB unit ) or if you prefer that in volume ,then
it will be 8,196 liters of CO2

Notes :
1 mol CO2 = 10^6 umols CO2 = 44 grams = 22.4 liters @ 25°C ,1 atm
1 mol CO2 needs 10 mols of quanta to be fixed. )
To play with it you will need :
a ) The digitized Rel. Spectral Power Distribution graph of a COB into y values .
Place them at the amber column of the tool named " RSPD "

b ) Using Cree PCT or a digitizer & spec datasheet plots of Vf vs If & output vs Io ,
you will have to enter the Vf and lumens output of the given COB at a given current .
Also enter the number of COBs used as also the light duration.
( enter values at the amber colored cells )

c) The spreadsheet needs OpenOffice (free download ) in order to work ...

d ) At cyan colored cells you get the results .

Have fun.

Click to expand...

Cheers.

stardustsailor said:

Well...
I'm not able to go to sleep ,tonight ...
So -just for the fun of it- made a new tool ...

A spreadsheet that calculates how many grams of CO2 your plant(s) fix per light cycle .

How it works :

Basically it multiplies the RQE McCree curve with the Cannabis L. Sativa absorptance spectrum.
The result is ,what I like to call " Photosynthetic Potentional " ak PP .
Then the spreadsheet multiplies PP with the light source's umol/nm (at a given power ).

The result is how many of these photons are used to fix carbon molecules per light cycle ...

As an example I've used the Cree CXb 3590 3000°K 80Ra 36V type,bin CB .
Driven at 1400 mA ( 1.4 A )

Assuming that all the emitted photons are being incident to leaf canopy ....
Then this particular COB has an PP efficiency of 74.12 % ( meaning that from all the photons emitted ,
that percentage is actually being used for carbon fixation ) and during the 12 hour light course ,
16.1 grams of CO2 are being fixed ( per single COB unit ) or if you prefer that in volume ,then
it will be 8,196 liters of CO2



Cheers.

Click to expand...

Thanks brother. Love when you are around these parts.


More heavy indicas next cycle is my suggestion for the sleep.

Greengenes707 said:

Thanks brother. Love when you are around these parts.


More heavy indicas next cycle is my suggestion for the sleep.

Click to expand...

And a comparison .....

Cree CXB 3590 3000°K 80Ra 36V type,bin CB versus Bridgelux Vero 29 version 1.2 (old model ) 3000°K 80Ra .

At 2 A driving current ,for 12 hour light duration :


Cree CXB 3590 3000°K 80Ra 36V CB
Dis.Power : 71.86 W
Lm/W : 144.073
CO2 grams fixed : 21.66
Volume of CO2 fixed : 11.02 lt
PP efficiency : 0.741

vs

Bridgelux Vero 29 version 1.2 3000°K 80Ra
Dis.Power : 74.8 W
Lm/W : 120.7
CO2 grams fixed : 19.13
Volume of CO2 fixed : 9.74 lt
PP efficiency : 0.739


Well in terms of radiant and luminous efficiency ,
clearly the CXB 3590 CB outperforms the Vero 29 1.2 ...

For almost 3 Watts less power dissipation ,CXB has a luminous efficiency ,almost 24 lm/w more than Vero 29 ...
Radiant efficiency is also better for CXb3590 ( ~44% ) than of VERO 29 ( ~38% )...

But ,the plants under both of them seem not to care that much ,about those figures ...

The difference of daily CO2 fixation ,is rather small ....

( Although for a full 70 days flowering time ,it will be 177.1 grams of CO2
fixed more ,under the CXB3590 vs the Vero 29 ...That is not a small difference ... )

Cheers.

@alesh

Brother ,'cause right now i'm pretty bored and tired to digitize the RSPD of the CXB3590 3000°K 90-92 Ra ,bin BD
( CXB3590-0000-000N0UBD30x )
I was wondering ...
Maybe you can do the dirty job and then supply us with the CO2 fixation results ...
( at 1400 mA & 2000mA )
...

I can do it ,of course ...But not today ...

Thanx and cheers.

stardustsailor said:

@alesh

Brother ,'cause right now i'm pretty bored and tired to digitize the RSPD of the CXB3590 3000°K 90-92 Ra ,bin BD
( CXB3590-0000-000N0UBD30x )
I was wondering ...
Maybe you can do the dirty job and then supply us with the CO2 fixation results ...
( at 1400 mA & 2000mA )
...

I can do it ,of course ...But not today ...

Thanx and cheers.

Click to expand...

I used values from PCT at 25°C.

alesh said:

I used values from PCT at 25°C.
View attachment 3587099

Click to expand...

Thanx,bro...
I've used values of PCT at 25°C for the CXB3590 ...
Still I've one question . The CXB3590 has the same VF for 1.4 and 2 A (being 34.84 V ) ?
( @2A isn't it 35.93 V ? )

Anyway ,,I did not expect a PP efficiency of 70% ..
I was hopping that it would 've been greater than of the 3000K 80Ra ..

Well,I did digitize the RSPD of the CXB3590 30006K 90Ra to doublecheck the figures ...

So..The BD bin @ Tc=25 C and @ 1.4 A gives these numbers at the spreadsheet :

LER : 276
Rad.Efficiency : 51,9%
Power Dis. : 48,776 W
lm/W : 143,42
PPF : 124,41 umols/sec
Mass of CO2 fixed in 12 hours : 16,62 grams
Volume of CO2 fixed in 12 hours :8,464 lt
PP eff .: 70,3 %

While @ 2A :

Rad.Efficiency : 47,4%
Power Dis. : 71,86 W
lm/W : 130,975
PPF : 167,38 umols/sec
Mass of CO2 fixed in 12 hours : 22,36 grams
Volume of CO2 fixed in 12 hours :11,387 lt
PP eff .: 70,3 %



Too much NIR/FR emission ...That's my explanation for the "low" numbers ...
Comparing to 3000° K 80Ra ...


This "extra" NIR/FR emission " cancels out " the gains of the 630 nm broad peak ,at the CXB 3000°K 90Ra ...
To be honest ,I expected a greater difference ,from the "standard" 3000 K 80 Ra ....
But that NIR/FR band ," ruins" the whole thing ...
Although ,I still trust ,that if used for "finishing " a grow cycle (mid to late flowering ) ,
the 3000°K 90 Ra ,possibly will give better yield (maybe slightly ) and/or thicker bud clusters ,
than the standard 3000 K 80Ra .

Cheers.

stardustsailor said:

Thanx,bro...
I've used values of PCT at 25°C for the CXB3590 ...
Still I've one question . The CXB3590 has the same VF for 1.4 and 2 A (being 34.84 V ) ?
( @2A isn't it 35.93 V ? )

Anyway ,,I did not expect a PP efficiency of 70% ..
I was hopping that it would 've been greater than of the 3000K 80Ra ..

Click to expand...

forgot
It's interesting that high CRI version has higher radiometric efficiency than standard 80CRI.

If the Lum/W Is the same across the BIN but the high CRI has a lower LER then isn't the high CRI always more efficient?

alesh said:

forgot
It's interesting that high CRI version has higher radiometric efficiency than standard 80CRI.

Click to expand...

nogod_ said:

If the Lum/W Is the same across the BIN but the high CRI has a lower LER then isn't the high CRI always more efficient?

Click to expand...

Sure but high CRI always comes in lower bins. Ie top bin for 3000K 90CRI min is BD while for 3000K 80CRI it's CB or even CD for 3500K.

3000K90CRI_min.csv.zip

a CIE Calculation results in 3500K for this file

Why interesting then?

alesh said:

forgot
It's interesting that high CRI version has higher radiometric efficiency than standard 80CRI.

Click to expand...

alesh said:

Sure but high CRI always comes in lower bins. Ie top bin for 3000K 90CRI min is BD while for 3000K 80CRI it's CB or even CD for 3500K.

Click to expand...

nogod_ said:

Why interesting then?

Click to expand...

CXB3590 is the only one I know of where the top bin 3000K/90CRI (BD) is more efficient than the top bin 3000K/80CRI (CB). For example, CXB3070 top bin 3000K 80CRI (AD) is more efficient than the top bin 3000K 90CRI (Z4).

How long do you think those 50pcs are going to last?

alesh said:

CXB3590 is the only one I know of where the top bin 3000K/90CRI (BD) is more efficient than the top bin 3000K/80CRI (CB). For example, CXB3070 top bin 3000K 80CRI (AD) is more efficient than the top bin 3000K 90CRI (Z4).

Click to expand...