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

stardustsailor

stardustsailor

Well-Known Member
MrFlux said:
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.
Click to expand...


The McCree RQE 1972a standard is still the most widely used one ,to normalise a given
light spectrum into it's photosynthetic efficiency ...

This standard has two different "action" spectrum curves ...

One to be used with quanta/photon/sec flux units (the RQE one ) and should be not used with PPF or PAR only ,
but for the whole range of 300-800 nm .

If you multiply the W/nm values of one light source ,with the number of photons per nm ( λ/ 119,708 ),
then you turn the power/energy/irradiance curve into quantum flux curve...
Multiply that with RQE/nm and you have the Photosynthetic Efficient ( quantum) Flux ..
( aka Photosynthesis 'weighted' photon flux ...)

Same thing is ,if you multiply RQE curve with with the number of photons per nm ( λ/ 119,708 )...
Then you get the second McCree action spectra curve ...(the one you've posted) ...
THis curve is to be convolved with the Intensity/Light power /Irradiance (in Watts ) oe Energy (J ) ..

Then you will get again the same resulting, Photosynthesis 'weighted' photon flux curve ,as with the first way ..

And this standard has proven itself for many years now,over awide variety of plant species ...

McCree suggests the first method ( RQE x Photon Flux ) of "weighting" a light spectrum ,
to it's photosynthetic efficiency ...



As for the "pay 'n ' play " DIN standard ...
I went the other way round ...
Play and Pay ....

Some hints ...To the method ...:lol:


Some Par/light meters companies ,actually allow you to download -for free-
a demo version of their software ...
Inside there,somewhere inside the program's files and folders ,
you might discover some useful files ...;-)
He-he !

Oh,for example ....
jeti instruments.JPG


...8-)...:P.....:bigjoint:....
"Free Demo Download ..."

....

But ,yes .,,
Both DIN standards are mostly focused/based on chlorophyll absorptance ,most probably ...
OOS-Chlorophyll-absorption.jpg
Thus the higher blue peak than red ...(at the old DIN one ...From 2000 )

Makes me wonder what actually they are using as "reference" ....of action ....
The photosynthetic efficiency of ChA & ChB as substances in relation to light ,
or the actual photosynthetic efficiency of an intact leaf / alive plant ?
If it was the second case ,then the absorptance curve should have been way different ,than
that "pink/violet -light" favouring duo of action curves ,taken from a chlorophyll solution ...
Anyway ...
..Osram seems to use this standard along with CaliforniaLightWorks ...

" Luminous output measured using a spectrometer-radiometer
with NIST traceable calibration (calibration certificate available upon request.)
Measurements are adjusted to account for plant spectral absorption according to DIN 5031-10.
For details on our luminous output measurements
and calculation techniques,please visit our website:www.californialightworks.com or contact us."

While Inda-Gro has it's "second thoughts " and another 'opinion'
about this DIN standardisation ...

" Part of the problem is that lighting manufactures
do not have a generally accepted industry
standard plant absorbance sensitivity curve that manufacturers
can point their lamps output data relative to that curve. The
problem has been identifying a meaningful
curve that is broad enough to co ver a majority of plant speci es net
absorption regions. Many manufacturers will refer to the German DIN Standard 5031-10 but this has not been
accepted as, nor should it be,a hard and fast standard for all plant species."

So,there's already a lot of debate about which standard should be accepted ...
debate.JPG


http://www.hdc.org.uk/sites/default/files/research_papers/PC 176 final report.pdf

LOL....


One I know ,for sure ,though ...

If an average HPS is weighted according to either DIN standards ,
is rendered as "useless" for horticultural utilisation ..
If same HPS is "weighted" with McCree standard RQE then ,
it shows some average to good photosynthetic efficiency ...
hps stnd 1.JPG
hps stnd 2.JPG


SONT Agro HPS ,DIN weighted ,gets a mere 1.49 ...W/kLum (PAR Watts: 2,44 / kLum)
While HQI BT metal halide ,gets a whoppin' 2.3 W/kLum (PAR Watts: 3.46 / kLum)

Real life yields and harvesting results ,point out ,that the good ol' trusty McCree RQE ,is probably the best standard for the industry ,to be accepted as a "hard and fast" one ....
(1,95 W/kLum vs 2,35 W/kLum SON / HQI )

The DIN ones smell "monochromatic led favoring " as also as "Greenhouse's bedding-leafy -veggie" plants
favouring ....A lot actually ...And they are to be used both with Watt/Square meter ,Watts or Joule power curves ...
Not with quantum fluxes ...Another weird aspect of that DIN standard ...

Cheers.
 
Last edited:
MrFlux

MrFlux

Well-Known Member
stardustsailor said:
McCree suggests the first method ( RQE x Photon Flux ) of "weighting" a light spectrum ,
to it's photosynthetic efficiency ...
Click to expand...
Yes this would give you a single number for each type of LED; You could use that to compare different LEDs.
Some hints ...To the method ...:lol:
Click to expand...
Ah you did some deep digging there!
Real life yields and harvesting results ,point out ,that the good ol' trusty McCree RQE ,is probably the best standard for the industry ,to be accepted as a "hard and fast" one ....
Click to expand...
The supplemental lighting in normal greenhouses is at a very low level; 200 umol would already be considered very high. The research on action spectra is also done at low light levels. But at 1000 umol, would you rather have more red or more green light? The extra red light would be absorbed and go to waste in the already saturated upper layer of the leaves, while the green light would penetrate deeper and be more useful.

I'm curious about the Wageningen action spectrum that you showed, I've never seen it before and can't find any references to it.
 
stardustsailor

stardustsailor

Well-Known Member
CaliWorthington said:
We'll soon see. :blsmoke:
Click to expand...

Depends on what you're actually growing ...

If you're growing sugar cane indoors ,or any other weird C4 plant(s) ,then
minimum limit of light energy given to plants ,on a daily basis should be more than 500 umoles / sec/sqm ,
for at least 16 hours ...
( minimum DLI : 28 mol/dia /sqm...==> 500umols/sec /sqm* ( 16*3600 )sec /1000000= 28,8 mols/dia/sqm)

If you're growin spinach,lettuce or alpha-alpha for some reason ,
then 8-10 umols /sec/ sqm for 8 hours ,would be fine ...

(DLI : 0,2-0,3 mol/dia/sqm ..)
Better a blue and red monochomatic led combo in that case ,for highest efficiency ,possible ...8-):fire:.....


If by any case you're growing weed ...
:P...

Then it takes about 400umoles/sec/sqm for 18 hours to saturate the plants with light ...
(DLI : 25,92mol/dia/sqm )

Ok ..some nasty Sats or Sat-Dom hybrid cultivars (aka strains<=never really liked the term..:cuss: ) ...
might need double that figure ... (800-900 umols/sec/sqm ) ......

Read specifically at end of page 3 ,beginning of page 4 on the pdf ...
read a bit further down ,to what usually happens if you go over the limits ...

http://www.controlledenvironments.org/Growth_Chamber_Handbook/Ch01.pdf

Nice e-handbook,BTW :
http://www.controlledenvironments.org/Growth_Chamber_Handbook/Plant_Growth_Chamber_Handbook.htm
 
stardustsailor

stardustsailor

Well-Known Member
For years now ,my growing space area , is one mere square meter ....
Sometimes i got up to 260-280 gr ,from that surface ..
But with lots of electrical power ... (>550Watts in total )
...
Now it takes a good DIY COB grow light ,with just four CXAs 3070 3000K to do the job ...
With more than enough flux for my mere single square meter ...

With almost same efficiency as a HPS ,with less heat radiated to plants ,less electric energy spend ,
way-way longer service life ,with more safety (from fire ,injury ,mercury poisoining ,etc ) and of course a better ,more
"complete" or "full" if you like spectrum ...(higher light quality ..)

max potentional of my DIY grow light.JPG

And it did not cost me a small fortune ...
No more than half a $K ....

Cheers...
:peace:
 
E

end_of_the_tunnel

Well-Known Member
stardustsailor said:
Depends on what you're actually growing ...

If you're growing sugar cane indoors ,or any other weird C4 plant(s) ,then
minimum limit of light energy given to plants ,on a daily basis should be more than 500 umoles / sec/sqm ,
for at least 16 hours ...
( minimum DLI : 28 mol/dia /sqm...==> 500umols/sec /sqm* ( 16*3600 )sec /1000000= 28,8 mols/dia/sqm)

If you're growin spinach,lettuce or alpha-alpha for some reason ,
then 8-10 umols /sec/ sqm for 8 hours ,would be fine ...

(DLI : 0,2-0,3 mol/dia/sqm ..)
Better a blue and red monochomatic led combo in that case ,for highest efficiency ,possible ...8-):fire:.....


If by any case you're growing weed ...
:P...

Then it takes about 400umoles/sec/sqm for 18 hours to saturate the plants with light ...
(DLI : 25,92mol/dia/sqm )

Ok ..some nasty Sats or Sat-Dom hybrid cultivars (aka strains<=never really liked the term..:cuss: ) ...
might need double that figure ... (800-900 umols/sec/sqm ) ......

Read specifically at end of page 3 ,beginning of page 4 on the pdf ...
read a bit further down ,to what usually happens if you go over the limits ...

http://www.controlledenvironments.org/Growth_Chamber_Handbook/Ch01.pdf

Nice e-handbook,BTW :
http://www.controlledenvironments.org/Growth_Chamber_Handbook/Plant_Growth_Chamber_Handbook.htm
Click to expand...
Update links.

Growth Chamber Handbook - NCERA-101

Edited by R.W. Langhans and T.W. Tibbitts North Central Regional Research Publication No. 340 Iowa Agriculture and Home Economics Experiment Station Special Report No. 99 Cover Title Page Contributors Preface Original Table of Contents Contents Chapter 1 - Radiation- John C. Sager and J. Craig...
www.controlledenvironments.org www.controlledenvironments.org
 
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