Periodic Led Dimming: Maximising Efficiencies ?

stardustsailor

stardustsailor

Well-Known Member
Ehm...

F@&%....

From where should I start blah-blah ?

Ok ...
Folks,you all led -growers out there ...
I need help here ...
Scientific ...
Technical ...
...
Phycological,maybe ...
Anyway ....

Well...
I forgot to mention something ...

Everyday ,around 15:00 till about 17:30 ,I lower the drive current of the CXA's (3070 ) from ~900mA to
~700mA....

Why I do such a thing ?

Well...Cause I can have the fans at lower speed ,thus less noise ,without case temperatures going over ~33°C ...(The fixture is just burning in ....)

Less noise because here ,during that period of time ,is not allowed to make lots of noise ..
(It is actually a law ... )
It's "noon resting time " ...
A natonal-wide 'Siesta -time' enforced by the Law !

Anyway...So,I'm probably overreacting and turn things down,a bit ,during those hours ...

Maybe it's just another crazy idea of mine ....

Maybe,I might be seeing things ,that do not exist @ all !

Still...
I just got to tell you those things ...
Maybe jus tfor a good ' laugh ',afterall ...

Anyway ...
Lady got crazy !

Maybe it's just her ! Good genes and good pheno !
Maybe it's the awesome CXA3070 3000K Z4 ..(@900mA ???? 4COL !!! )
Maybe again it's all the above ....
Combined with the fact of that 'dimming ' and 'increasing' again ....

Right now ,I do not have much time ....
To continue ...
But the cubes are thrown ,now ....

-Photoinhibition .
-Constant irradiation for 18 or 12 hours ,or so ...
-PS 2 and D1 protein .
-Recovery of PS2 and photosynthetic yield .
-Photo-acclimation.
-High irradiances.
-Beta-carotene .

.....

And Periodic LED Dimming Function.

(For example :driving current ," ripples" periodicly from i.e. 400mA to 2000mA ...
(duration at 'peaks' can be short ,while the 'interval ' between peaks can be 'prolonged"..
Imagine a sinusoidal waveform of current ,with peaks at 400mA and 2000mA or even more
for the CXA3070...Like a sunny sky ,with 'breezing' clouds passing by !!! 8)...
Everybody needs a " short rest" ..Specially during .."hard work" ...
Even plants ...Specially the "light needy " ones ! ...
Throughout the whole 12 hour regime ......

Maximising photosynthesis and per dia (daily ) photosynthetic yields ..
Maximising el. energy usage vs final product mass ?
Details remain still unknown ..)

http://www.plantphysiol.org/content/104/3/1033.short

http://www.google.gr/search?q=D1 protein &ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:el:official&client=firefox-a&channel=sb&gfe_rd=cr&ei=c7N8U-ySCOug8wfstIDQAw

http://en.wikipedia.org/wiki/Photosystem_II

http://en.wikipedia.org/wiki/Beta-Carotene

http://en.wikipedia.org/wiki/Photoinhibition

http://www.ias.ac.in/jarch/jbiosci/20/35-47.pdf

http://www.google.gr/search?q=b-carotene absorption&client=firefox-a&hs=5fT&rls=org.mozilla:el:official&channel=sb&tbm=isch&tbo=u&source=univ&sa=X&ei=trR8U7rjPMis7Qb244HYBg&ved=0CDEQsAQ&biw=1280&bih=902

http://www.life.illinois.edu/govindjee/Part2/31_Adir_etal.pdf

http://plantsinaction.science.uq.edu.au/edition1/?q=content/12-1-2-photoinhibition-and-photoprotection

http://www.helsinki.fi/fdpps/PhD theses/Sarvikas.pdf


Thank you in advance ,to all those willing to help ...
Either we're going to have plenty of fun ...
Either we're going to take things 'further" ,once more ...

Cheers !
:bigjoint:
 
Last edited:
bicit

bicit

Well-Known Member
Would frequent dimming reduce the life span of the LED's or drivers at all? Maybe combine with CO2 supplementation during the peaks when light is most intense.
 
stardustsailor

stardustsailor

Well-Known Member
bicit said:
Would frequent dimming reduce the life span of the LED's or drivers at all? Maybe combine with CO2 supplementation during the peaks when light is most intense.
Click to expand...

That is a very crucial question to be answered.One more door opened !

Very good,bicit !
Very important note ...

CO2-intense irradiance-elevated temps ...
Yes...
Good combo ...
For short-while ...
 
bicit

bicit

Well-Known Member
stardustsailor said:
That is a very crucial question to be answered.One more door opened !

Very good,bicit !
Very important note ...

CO2-intense irradiance-elevated temps ...
Yes...
Good combo ...
For short-while ...
Click to expand...
It's gonna take a while to read through all of that. Lots and lots of info on an already crowded plate from the all you can eat buffet of info otherwise known as the internet.
 
stardustsailor

stardustsailor

Well-Known Member
Positivity said:
I like the idea of short peaks. Maybe a midday peak for just a hour. Would be interesting to see the difference of a plant grown with the noon peak and without. Probably be a good first step.
Click to expand...
So ,you suggest the "Nature's Single Parabola" ...



Start from ~ xxx mA ..
Increase...
Peak at ~xxxx mA
Decrease ...
End at ~xxx mA
...

Yes.Very good .
But ...

The microcontroller that would automatically operate the ' P.L.D. ' ,has to be the actual
on/off timer .
If it is easily done ,then it's rather ok ...

From the other hand ...

Continuous periodic 'rippling',"frees' proccessing power from microcontroler ,as it does not have to be a timer also ..

And it might be more efficient ( this needs to be calculated ..Not by me that's for sure ...),if there are more ,shorter
intervals between peaks ('zenith'/ 'nadir ' current values ...Nice names ...PLD !! ..:P...)

But ,both cases need more investigation ...

The one you suggest ,Pos ,actually has shown great results ,in some experiments that were done ..
Have to find those research papers ...I'' give it a try ...It's something with the IR / dawn-dusk effect /
Pfr-Pr under artif. illumination horticulture .....)
 
SupraSPL

SupraSPL

Well-Known Member
I recall there was a grower in icmag (secondtry) who linked a bunch of documentation supporting the theory giving the plants a noon break.

Incendentally KNNA and I were arguing with secondtry about HID vs LED and secondtry claimed to have given knnas spreadsheet to Sanjay Yoshi for review.
 
stardustsailor

stardustsailor

Well-Known Member
bicit said:
It's gonna take a while to read through all of that. Lots and lots of info on an already crowded plate from the all you can eat buffet of info otherwise known as the internet.
Click to expand...

Start from here if you like ...

http://www.helsinki.fi/fdpps/PhD theses/Sarvikas.pdf

Probably best place to start for the issue ...
I know it has plenty of biochemistry inside ,just run through and note what you actually understand ...
(Althought as 've you said it youself ...It's rather easy to 'decode' that 'complex' biochemistry reactions ,
described ,by just using the web ...Easy ...Takes a bit time ,more ...That's all ..
Skip a TV-broadcasted football game ,for once and study some plant bio-chemistry !!! :P

LOL !!
Cheers .
 
stardustsailor

stardustsailor

Well-Known Member
SupraSPL said:
I recall there was a grower in icmag (secondtry) who linked a bunch of documentation supporting the theory giving the plants a noon break.
Click to expand...
Like I do !
Opposite of what's happening actually in nature ...

Start at high irradiance ( 900mA ..:P..) and drop at noun for couple of hours ,and then high again ..,!


It seems that is affecting,actually, the plant...
Way much,if it is so...
 
Last edited:
Mechmike

Mechmike

Well-Known Member
stardustsailor said:
Ehm...

F@&%....

From where should I start blah-blah ?

Ok ...
Folks,you all led -growers out there ...
I need help here ...
Scientific ...
Technical ...
...
Phycological,maybe ...
Anyway ....

Well...
I forgot to mention something ...

Everyday ,around 15:00 till about 17:30 ,I lower the drive current of the CXA's (3070 ) from ~900mA to
~700mA....

Why I do such a thing ?

Well...Cause I can have the fans at lower speed ,thus less noise ,without case temperatures going over ~33°C ...(The fixture is just burning in ....)

Less noise because here ,during that period of time ,is not allowed to make lots of noise ..
(It is actually a law ... )
It's "noon resting time " ...
A natonal-wide 'Siesta -time' enforced by the Law !

Anyway...So,I'm probably overreacting and turn things down,a bit ,during those hours ...

Maybe it's just another crazy idea of mine ....

Maybe,I might be seeing things ,that do not exist @ all !

Still...
I just got to tell you those things ...
Maybe jus tfor a good ' laugh ',afterall ...

Anyway ...
Lady got crazy !

Maybe it's just her ! Good genes and good pheno !
Maybe it's the awesome CXA3070 3000K Z4 ..(@900mA ???? 4COL !!! )
Maybe again it's all the above ....
Combined with the fact of that 'dimming ' and 'increasing' again ....

Right now ,I do not have much time ....
To continue ...
But the cubes are thrown ,now ....

-Photoinhibition .
-Constant irradiation for 18 or 12 hours ,or so ...
-PS 2 and D1 protein .
-Recovery of PS2 and photosynthetic yield .
-Photo-acclimation.
-High irradiances.
-Beta-carotene .

.....

And Periodic LED Dimming Function.

(For example :driving current ," ripples" periodicly from i.e. 400mA to 2000mA ...
(duration at 'peaks' can be short ,while the 'interval ' between peaks can be 'prolonged"..
Imagine a sinusoidal waveform of current ,with peaks at 400mA and 2000mA or even more
for the CXA3070...Like a sunny sky ,with 'breezing' clouds passing by !!! 8)...
Everybody needs a " short rest" ..Specially during .."hard work" ...
Even plants ...Specially the "light needy " ones ! ...
Throughout the whole 12 hour regime ......

Maximising photosynthesis and per dia (daily ) photosynthetic yields ..
Maximising el. energy usage vs final product mass ?
Details remain still unknown ..)

http://www.plantphysiol.org/content/104/3/1033.short

http://www.google.gr/search?q=D1 protein &ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:el:official&client=firefox-a&channel=sb&gfe_rd=cr&ei=c7N8U-ySCOug8wfstIDQAw

http://en.wikipedia.org/wiki/Photosystem_II

http://en.wikipedia.org/wiki/Beta-Carotene

http://en.wikipedia.org/wiki/Photoinhibition

http://www.ias.ac.in/jarch/jbiosci/20/35-47.pdf

http://www.google.gr/search?q=b-carotene absorption&client=firefox-a&hs=5fT&rls=org.mozilla:el:official&channel=sb&tbm=isch&tbo=u&source=univ&sa=X&ei=trR8U7rjPMis7Qb244HYBg&ved=0CDEQsAQ&biw=1280&bih=902

http://www.life.illinois.edu/govindjee/Part2/31_Adir_etal.pdf

http://plantsinaction.science.uq.edu.au/edition1/?q=content/12-1-2-photoinhibition-and-photoprotection

http://www.helsinki.fi/fdpps/PhD theses/Sarvikas.pdf


Thank you in advance ,to all those willing to help ...
Either we're going to have plenty of fun ...
Either we're going to take things 'further" ,once more ...

Cheers !
:bigjoint:
Click to expand...
That's an interesting concept. If anyone can decipher this, it's you. I think that whatever I can do to emulate the natural environment in which the plant evolved assists the plant. I have and still use a light mover because I want to emulate the movement of light over the leaves surfaces just a occurs on Earth under the sun.
 
stardustsailor

stardustsailor

Well-Known Member
http://hortsci.ashspublications.org/content/40/3/645.abstract

Daily light integral (DLI) describes the rate at which photosynthetically active radiation is delivered over a 24-hour period and is a useful measurement for describing the greenhouse light environment. A study was conducted to quantify the growth and flowering responses of bedding plants to DLI. Eight bedding plant species [ageratum (Ageratum houstonianum L.), begonia (Begonia ×semperflorens-cultorum L.), impatiens (Impatiens wallerana L.), marigold (Tagetes erecta L.), petunia (Petunia ×hybrida Juss.), salvia (Salvia coccinea L.), vinca (Catharanthus roseus L.), and zinnia (Zinnia elegans L.)] were grown outdoors in direct solar radiation or under one of three shade cloths (50, 70 or 90% photosynthetic photon flux (PPF) reduction) that provided DLI treatments ranging from 5 to 43 mol·m–2·d–1. The total plant dry mass increased for all species, except begonia and impatiens, as DLI increased from 5 to 43 mol·m–2·d–1. Total plant dry mass of begonia and impatiens increased as DLI increased from 5 to 19 mol·m–2·d–1. Impatiens, begonia, salvia, ageratum, petunia, vinca, zinnia, and marigold achieved 50% of their maximum flower dry mass at 7, 8, 12, 14, 19, 20, 22, and 23 mol·m–2·d–1, respectively. The highest flower number for petunia, salvia, vinca, and zinnia occurred at 43 mol·m–2·d–1. Time to flower decreased for all species, except begonia and impatiens, as DLI increased to 19 or 43 mol·m–2·d–1. There was no consistent plant height response to DLI across species, although the shoot and flower dry mass per unit height increased for all species as DLI increased from 5 to 43 mol·m–2·d–1. Guidelines for managing DLI for bedding plant production in greenhouses are discussed.


Most of them flowering plants,also...
 
stardustsailor

stardustsailor

Well-Known Member
Mechmike said:
That's an interesting concept. If anyone can decipher this, it's you. I think that whatever I can do to emulate the natural environment in which the plant evolved assists the plant. I have and still use a light mover because I want to emulate the movement of light over the leaves surfaces just a occurs on Earth under the sun.
Click to expand...
Actually a light mover does that exactly !
Are yields under a light mover increased ?
(not total yields -per plant yields...)
Do individual plants yield less,same or more with a light mover than without(under constant irradiation )..
Yields per total ,arefor sure higher with a light mover than without ,as more surface (thus plants) is being irradiated,at first case .

But what about as individual plants ?
As ' units' ?
 
Mechmike

Mechmike

Well-Known Member
stardustsailor said:
Actually a light mover does that exactly !
Are yields under a light mover increased ?
(not total yields -per plant yields...)
Do individual plants yield less,same or more with a light mover than without(under constant irradiation )..
Yields per total ,arefor sure higher with a light mover than without ,as more surface (thus plants) is being irradiated,at first case .

But what about as individual plants ?
As ' units' ?
Click to expand...
I like it simple. Better (not necessarily more) nutrition (in terms of light) = happier plants = better yields.
 
stardustsailor

stardustsailor

Well-Known Member
60 mol/ m2/ d... (max at South East States ..Summertime ...)
,.....

" 1 day " = 12 h (at flowering ) ....=12 * 60 *60 sec =>
" Dia " = 43.200 sec

60 mol = 60 000 mmol = 60 000 000 umol

60 000 000 / 43 200 = 1388,8 umol/sec/ sq.m
Steady for 12 hours ....

In order to artificialy provide/ recreate the same DLI to mj plants ,
as nature does provide in field grown plants at South East USA.....
 
stardustsailor

stardustsailor

Well-Known Member
1388,8 umol/sec/ sq.m ,constantly for 12 hours ,
most probably is enough energy per sec / power to cause -severe-photoinhibition,
to most of higher plants ...

:fire:
So ...?
 
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