CXA 3000°K 80 vs 93 CRI .An Estimation.

stardustsailor

Well-Known Member
So If I understand well, Cxa 3000K driven at 1400mA provide the maximum light needed for a square meter.
If used in more than 52W than not only it would be inefficient but it could also harm the plant if all the other factor are not perfect such as CO2 supplementation and quick available nutrients.
Nice, I will stick to 35W per/m2 for now then.
1 square meter = ~9 square feet ....
max limit is ......450 W / sqr.meter = 50 W / square foot.
 

stardustsailor

Well-Known Member
So..

In order to reach the ' Photosynthetic photosaturation limits' of one square meter of grow space (~9sqr.feet) ,
using Cree CXA3070 3000°K ,80CRI arrays ,bin AB ,at 1400mA drive current
and with a cooling design ,that will provide a stable Tc = 55°C ...

15 pieces are enough,for the job ....

square meter limit.JPG


Cheers.
 

speedyganga

Well-Known Member
LOL, I meant 1 square foot of course. I am not use to this measure but more to the square meter so it come naturally ;)
Though I would love to have a big 400W cxa at 40% of efficiency in da house :fire:
A meter square to power would make about 1200$ for the light then. The price really begin to get down :cool:
 
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stardustsailor

Well-Known Member
LOL, I meant 1 square foot of course. I am not use to this measure but more to the square meter so it come naturally ;)
Though I would love to have a big 400W cxa at 40% of efficiency in da house :fire:
A meter square to power would make about 1200$ for the light then. The price really begin to get down :cool:
I 'm really leaning towards the assumption ,that no more than 10-12 CXAs(of the above case ) should be used ,
per square meter ...

Driven at 1400mA ,ten to 12 Cxas AB bin ,will be more than fine (if still not being kinda much ..)

Do not forget ..
Horticultural illumination has four basic characteristics to take into consideration

- Quality (spectrum )
-Quantity (flux,radiant power,irradiance )
-Space (incident angle,dispersion ,distance,homogeneity,etc)

and last but not least

-Time .(duration)

12 hours of constant (high) irradiation ,does not happen nowhere upon
the planet Earth.Is Abnormal situation ....

Spring/Autumn at Equatorial zones ,might resemble that a bit ,but irradiance still is not constant from
8:00 am to 8:00 pm for example ...
While on a grow tent it is ....

Summertime ,close to North pole (*for the nothern Hemisphere ) ,Sweden let's say ..
Daylight lasts for almost all day long ..close to 24/24 ...With almost constant irradiance..
But irradiance is way low ...At average ~400-600 umols/sec (-900 umol/sec max noon peak )

Comparing to i.e Hellas,with a sunlight of average 1000umol/sec ( ~2000umol/sec noon peak) power and a duration of ~14 Hours ,at same time of year.

A 12 hours light regime ,under constant & high ( >1000umol/sec ) irradiation, is actually "overdriving" the photosynthetic systems of most plant species .


so @1400mA 10-12 pieces of AB bins per 1 square meter of leaf canopy area(ideally) ,
might be more than enough actually .....

12x 1400ab.JPG
 
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speedyganga

Well-Known Member
12 hours of constant (high) irradiation ,does not happen nowhere upon
the planet Earth.Is Abnormal situation ....


Well, here I have to say indoor is abnormal so no problem for me. The soil pot are abnormal, the areo/hydro CO2 supplement are all abnormal. It does make a different weed but doesn't matter to me.

Spring/Autumn at Equatorial zones ,might resemble that a bit ,but irradiance still is not constant from
8:00 am to 8:00 pm for example ...
While on a grow tent it is ....

Where I lived, for a practical experimentation in my studies we had a device (can't remember it's name lol) to calculate the irradiance. At the sun highest intensity time (around mid day), we where at 900W/sq meter. I am sure of this value btw. When some clouds appeared it was more light 400W/sq meter. And I said to myself, indoor is 400/600W per m2 all the day while the sun is on average 500W at the peak of the day. I personally prefer indoor weed and I understood why at this time.

Summertime ,close to North pole (*for the nothern Hemisphere ) ,Sweden let's say ..
Daylight lasts for almost all day long ..close to 24/24 ...With almost constant irradiance..
But irradiance is way low ...At average ~400-600 umols/sec (-900 umol/sec max noon peak )

Comparing to i.e Hellas,with a sunlight of average 1000umol/sec ( ~2000umol/sec noon peak) power and a duration of ~14 Hours ,at same time of year.

A 12 hours light regime ,under constant & high ( >1000umol/sec ) irradiation, is actually "overdriving" the photosynthetic systems of most plant species .

I live in europe, and I go north of africa every year. I learned to grow there with family, I have grown some myself. I can tell you something : the average there is not 900W/sq meter at mid day, in sumer I remember once a temperature of 52°C (taken under sun so not really accurate but at least 45°C in the shadow). The canna can flower almost at any period of the year overthere and the bud are much much better than any indoor grow or european outdoor grow if done by yourself. (in my opinion)
I guess same thing is happening in Afghanistan or Mexico. And canna is natural in these country it is a real weed in the proper sense of the terms. So It is use to this amount of light.



All this to say: I think you can go at more than 450W PAR /meter.
The only thing is there is no point in term of efficiency in indoor...

so @1400mA 10-12 pieces of AB bins per 1 square meter of leaf canopy area(ideally) ,
might be more than enough actually .....
Here I totally agree with you. Indoor and outdoor are different especially since we have no dimmer to imitate the amount of light increasing yet (I saw your thread and your idea is definitely possible look at aquarium light ;) ).

View attachment 3177689
Btw, the seed we grow are generally selected in europe or America where the sun is less powerful. Perhaps by doing the selection the one which performed the best where the one needing less light and so we kept them.
Landrace can undergo harder condition including dry soil, high temperature and lots of light but are less good in our country and vice versa for our variety who perform so so in those condition... (I am myself a lover of our seeds but hate when people bring amnesia haze or northern light to grow them in north africa=> very good weed but not original one, and the taste of a good landrace, adapted by mother nature to the place is ... can't describe)
 

stardustsailor

Well-Known Member
The lower output was always clear. But with the RQE factored in...the spectral efficiency gains seem to be near nothing.


:fire:

Seems that both Mr.Flux and me ,we 're on the same thinking path with the official scientific community ...

Check this out ...

COMMISSION INTERNATIONALE DE L'ÉCLAIRAGE
INTERNATIONAL COMMISSION ON ILLUMINATION
INTERNATIONALE BELEUCHTUNGSKOMMISSION



Minutes of the CIE Division 6 Meeting
Paris,France
9 am,17 April 2013


Page 4 .....
http://files.cie.co.at/705_2013 Paris.pdf

Καταγραφήbn.JPG


:P....

Photosynthetic Efficient Flux (PFE )
 

stardustsailor

Well-Known Member
Also .....

" Fig. 2. The quantum (PPF) response when all photons are weighted equally between 400 and 700 nm; and the relative quantum efficiency curve as determined by the average plant response for photosynthesis (from McCree, 1972a). The quantum response overestimates the photosynthetic value of photons between 400 and about 550 nm, but underestimates the photosynthetic value of photons below 400 and above 700 nm. "

http://biology.mcgill.ca/phytotron/lightwkshp1994/1.5 Bugbee/Bugbee text.htm

BTW: Figure 2 of the above link is pretty much useless for digitizing the values of RQE from it ....!!!
Check out why's that so ...Bad (skewed ) scanned ....
skewed graph.JPG

Check also here ....

http://www.licor.com/env/pdf/light/TechNote126.pdf

In order to evaluate how efficiently light is used to
drive photosynthesis over a given wavelength range,
photosynthetic rates can be normalized by the
energy incident on the leaf (relative action spec-
trum; Figure 1b)
or by the quanta of light absorbed
by the leaf (relative quantum yield; Figure 1c) at
each wavelength. As might be expected, the

wavelength range of the spectrum for relative
quantum yield coincides with the wavelength range
for the relative action spectrum; however, the
relative quantum yield is much less variable across
the entire spectral range of response. McCree
(1972b), compared variations in the relationships
between photosynthesis and different measures of
light and found that variation was reduced by a

factor of two when photosynthesis was normalized
to quantum flux (μmol m-2s-1) rather than irradiance (energy units, W m-2).
This means photons of any wavelength between 400 and 700 nm can drive photosynthesis with
similar efficiency. Quantitatively, we know the photosynthetic reactions require about 8 to 10 photons for each
molecule of CO2 fixed
(Nobel 1991).
parrqe.JPG

 

stardustsailor

Well-Known Member
And this is something for Mr.Flux to read ...
Regarding a post about PS at <400 nm ...

" Figure 1.10 Leaves absorb visible light very effectively (85% for the waveband between 400 and 700nm; solid curve).Wavelengths corresponding to green light are absorbed less effectively (absorptance drops to c. 0.75). Beyond 700 nm (infrared band) absorptance drops to near zero, and forestalls leaf heating from this source of energy. Quantum yield is referenced to values obtained in red light (600-625 nm), which is most effective in driving photosynthesis, requiring about 10 quanta per CO2 assimilated (based on high-precision leaf gas exchange) compared with about 12 quanta at the blue peak (450 nm). Quantum yield shows a bimodal response to wavelength. Absorptance drops beyond 700 nm but quantum yield drops off even faster because PSII (responsible for O2 generation) absorbs around 680 nm and cannot use quanta at longer wavelengths in this measuring system. UV wavelengths (below 400 nm) are capable of driving photosynthesis, but as a protective adaptation vascular plants accumulate a chemical ‘sunscreen’ in response to UV exposure. Field-grown plants are especially rich in these substances so that absorbed UV is dissipated harmlessly, lowering quantum yield compared with growth-chamber plants. (Based on McCree 1972) "


http://plantsinaction.science.uq.edu.au/book/export/html/13


And from what it seems ,it's not that easy to find a decent RQE graph ,to digitize ....


Cheers...
 

stardustsailor

Well-Known Member
DIN5031-10-neu Standard.
Physics of radiation in the field of optics and illuminating engineering -
Part 10: Photobiologically effective radiation, quantities, symbols and actions

Photosynthesis Action Spectrum.
din5031-10-neu graph.JPG

http://www.fh-muenster.de/fb1/downloads/personal/juestel/juestel/Action_Spectra.pdf
http://i115srv2.vu-wien.ac.at/uv/actionspectra/uv_actionspecs.htm

Analytical Table :
din5031-10-neu graph_table.JPG


new cxa main.JPG

(I've redigitized the CXA 3000K 80 CRI rel.graph (yes..once more ...)
Mr.Flux ,it seems that our LER estimations for this array ,are closing together ,more and more ...
 
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stardustsailor

Well-Known Member
I've no idea which factors they did evaluate for the DIN5031-10-alt ...
it seems like an action spectrum for ...aquatic plants and not soil plants ...


I still like the ( most used ) Action Spectrum ,of McCree,1972a.RQE
Anyway ,the german DIN5031-10-neu ,seems also rather good ..
Although I still do not understand the 80% photosynthetic efficiency given to blue wls ...
Based on what ?
(it seems like a "monochromatic led " oriented standard ...)
Anyway...Those people from the DIN standardization ,know a lot more than me ,
so I guess ,we 'll have to trust them ....

Still ,I'm going to use both standards ...
(McCree,1972a RQE & DIN5031-10-neu )

(The McCree action spectra ,shown at pic that Mr.Flux posted ,i
is actually not the RQE but the Irradiance Efficiency .
McCree suggested that :
" compared variations in the relationships
between photosynthesis and different measures of
light and found that variation was reduced by a
factor of two when photosynthesis was normalized
to quantum flux (μmol m-2s-1) rather than irradiance (energy units, W m-2). "

McCree1972aRQE_vs_DIN50310-10-neu.JPG
 

stardustsailor

Well-Known Member
So,Mr.Flux ....

About the Photosynthetic Efficient Flux :

I think the most appropriate way would be to
normalise the Absolute Quantum Flux spectrum of an artificial horticultural light source ,
with the McCree1972 RQE (and not the irradiance/energy one ..)

While normalising an Absolute Radiant Power ( Φ ) spectrum ,it would be more
appropriate to do it with the DIN5031-10-neu.
(As it takes more power in blue wls ,in order to increase the photon flux ,than in red ones ...
Maybe that's why blue wls get a 0.8 factor ... )



So,what do you think about :

μmoles/sec x McCree1972 RQE = Photosynthetic Efficient Flux

Watts (or J ) x DIN5031-10-neu = Photosynthetic Efficient Radiant Power (or Energy ,respectively ).....

Although...The older DIN standard seems better for that job ..
As it has the 100% values on blue wls% ...
Meaning actually that it takes lots of blue radiant power/energy ,in
order to get a sufficient number of quanta ,at those wls ...
More than in red wls ,at least ...Where for same amount of radiant power ,
quantum flux is almost double ,than in blue ones ..


I'm still rather ,confused about it ...
Should the new DIN5031-10-neu standard be used like the McCree1972 RQE ?
For normalising efficiency of quantum flux units, instead of power/energy units ?

Then it surely favors deep red quanta ,along with blue ones...
( smelling the 'monochromatic leds' ,now ? )

It's seems that the new DIN5031-10-neu standard it's based on /taking into account the light absorptance somehow..

Cheers.
:peace:
 
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stardustsailor

Well-Known Member
But I'm pretty sure about the two McCree graphs ....

Multiply curve of RQE ....
McCree1972 stndrd.png



With ( λ )/ 119,708
umolnmw.JPG


and you'will get this McCree "Power/Energy units " normalising curve ..
s(lambda)_b.png


Roughly ....
McCree1972aRQE_vs_DIN50310-10-neu vs MCree RadPwr Action Spectrum.JPG


...
Cheers.
 

MrFlux

Well-Known Member
I have no clue how the DIN data was obtained but believe it's mostly geared towards green leafy vegetables. DIN is not an open scientific institute, it's pay to play unfortunately. The graph I posted is indeed based on incident power.

As a suggestion, you can convolve one action spectrum with a LED spectrum. This gives a dimensionless number that can be expressed as a percentage; It would signify the "spectral efficiency" of the LED in relation to the chosen action spectrum. For white LEDs with the McCree data it tends to be 85% +- a few percent.
 

bicit

Well-Known Member
So..

In order to reach the ' Photosynthetic photosaturation limits' of one square meter of grow space (~9sqr.feet) ,
using Cree CXA3070 3000°K ,80CRI arrays ,bin AB ,at 1400mA drive current
and with a cooling design ,that will provide a stable Tc = 55°C ...

15 pieces are enough,for the job ....
Would that still hold true for high tech gardeners that use non-organic hydro and CO2 supplementation?
 
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