Math behind
- Thread starter alesh
- Start date
end_of_the_tunnel
Well-Known Member
Thanks Alesh, wherever you are. A beautiful gift to the community.
My very first post with my new account ..
Well , it's been quite some time since my last post @ RIU .
Forgot my email used to sign -in and the account password also .
Made a new account mainly for applying this question only -for the time being ...
:
I keep reading that the LER of the Samsung LM561C @3000°K 80Ra is 321,6 lumens/Watt and it's PPE ( aka QER ) is 4,86 μmoles/J .
Still...
Doing the math (after carefully digitizing the LED's SPD,of course ... ) I keep getting different values .
LER : 333,33 lum/W & PPE : 4,811 μmoles/J for the photosynthetic active wl range of 400 -700 nm *,
for both LER & PPE ( " QER " ) .
Thus ,also getting a PAR multiplier of 0.01444 μmoles/sec/lm .
Any help towards enlightment will be much appreciated .
Thanx in advance !
SDS
*
Using the biologically active wavelength range of 380-780 nm to calculate LER and PPE would lead into accounting extra photon flux ,
which is not actually used for photosynthesis .So ,in order to acquire a correct PAR multiplier both
the LER and PPE should be calculated only for the photosynthetic active wl range of 400 -700 nm.
A pic from the digitizing job ...
Well , it's been quite some time since my last post @ RIU .
Forgot my email used to sign -in and the account password also .
Made a new account mainly for applying this question only -for the time being ...
:I keep reading that the LER of the Samsung LM561C @3000°K 80Ra is 321,6 lumens/Watt and it's PPE ( aka QER ) is 4,86 μmoles/J .
Still...
Doing the math (after carefully digitizing the LED's SPD,of course ... ) I keep getting different values .
LER : 333,33 lum/W & PPE : 4,811 μmoles/J for the photosynthetic active wl range of 400 -700 nm *,
for both LER & PPE ( " QER " ) .
Thus ,also getting a PAR multiplier of 0.01444 μmoles/sec/lm .
Any help towards enlightment will be much appreciated .
Thanx in advance !
SDS
*
Using the biologically active wavelength range of 380-780 nm to calculate LER and PPE would lead into accounting extra photon flux ,
which is not actually used for photosynthesis .So ,in order to acquire a correct PAR multiplier both
the LER and PPE should be calculated only for the photosynthetic active wl range of 400 -700 nm.
A pic from the digitizing job ...
Last edited:
alesh
Well-Known Member
Hey SDS, how are you man? Long time no see. Sorry for the late answer, not really checking regurarly.My very first post with my new account ..
Well , it's been quite some time since my last post @ RIU .
Forgot my email used to sign -in and the account password also .
Made a new account mainly for applying this question only -for the time being ...
I keep reading that the LER of the Samsung LM561C @3000°K 80Ra is 321,6 lumens/Watt and it's PPE ( aka QER ) is 4,86 μmoles/J .
Still...
Doing the math (after carefully digitizing the LED's SPD,of course ... ) I keep getting different values .
LER : 333,33 lum/W & PPE : 4,811 μmoles/J for the photosynthetic active wl range of 400 -700 nm *,
for both LER & PPE ( " QER " ) .
Thus ,also getting a PAR multiplier of 0.01444 μmoles/sec/lm .
Any help towards enlightment will be much appreciated .
Thanx in advance !
SDS
*
Using the biologically active wavelength range of 380-780 nm to calculate LER and PPE would lead into accounting extra photon flux ,
which is not actually used for photosynthesis .So ,in order to acquire a correct PAR multiplier both
the LER and PPE should be calculated only for the photosynthetic active wl range of 400 -700 nm.
A pic from the digitizing job ...
Going through my spreadsheets I've got LM561C @3000°K 80Ra @ 324.2 lm/W & 4.84 µmol/J for the 380-780nm range and @
The attached *.txt is actually a csv export.
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Hey brother alesh !
Yes,long time no see !
I'm a family -man now ,LOL !
Been away from growing for a while and now it's about time to grow some herb again !
Still ,the Vero's Gen 6 seem old for nowdays standards .
Been thinking to upgrade to something like F series and maybe throw in some 660 reds to get a more "Fluencei-sh" spectrum .
Thanx for the SPD ,I will check it ASAP .
The attached *. txt is my version of the digitized spd (range 400-700 nm )
Yes,long time no see !
I'm a family -man now ,LOL !
Been away from growing for a while and now it's about time to grow some herb again !
Still ,the Vero's Gen 6 seem old for nowdays standards .
Been thinking to upgrade to something like F series and maybe throw in some 660 reds to get a more "Fluencei-sh" spectrum .
Thanx for the SPD ,I will check it ASAP .
The attached *. txt is my version of the digitized spd (range 400-700 nm )
alesh
Well-Known Member
A family man! Congratz then. After years I'm a student now again lol. And I'm growing mostly outdoors now.
I'm afraid I messed up earlier. I calculated LER over the 400-700 nm range wrongly. Once corrected, I'm getting 332.5 lm/W. I'm sorry. BTW I'm getting 333.6 lm/W & 4.81 µmol/J from that SPD of yours. Reasonably close I'd say.
But I have to admit that I see no point in using LER over the 400-700 nm range. Lumens are defined over a broader spectrum. And I also believe it's incorrect to use just the 400-700 nm data for PPE/LER. I think you have to use the whole 380-780 nm range (at least) for the calculations. That explains the discrepancy between my calculated PPE/QER over the 400-700nm range and yours (4.69 vs 4.81). By using just the 400-700 nm data, you're pretending there's no radiant power beyond 700 nm. But the correct approach, in my opinion, is just not to count photons outside of the range. But the radiant power is there (although perhaps wasted for photosynthesis). Same goes for LER actually but the error is much smaller as the luminosity functions drops close to zero outside of the 400-700 nm range.
I'm afraid I messed up earlier. I calculated LER over the 400-700 nm range wrongly. Once corrected, I'm getting 332.5 lm/W. I'm sorry. BTW I'm getting 333.6 lm/W & 4.81 µmol/J from that SPD of yours. Reasonably close I'd say.
But I have to admit that I see no point in using LER over the 400-700 nm range. Lumens are defined over a broader spectrum. And I also believe it's incorrect to use just the 400-700 nm data for PPE/LER. I think you have to use the whole 380-780 nm range (at least) for the calculations. That explains the discrepancy between my calculated PPE/QER over the 400-700nm range and yours (4.69 vs 4.81). By using just the 400-700 nm data, you're pretending there's no radiant power beyond 700 nm. But the correct approach, in my opinion, is just not to count photons outside of the range. But the radiant power is there (although perhaps wasted for photosynthesis). Same goes for LER actually but the error is much smaller as the luminosity functions drops close to zero outside of the 400-700 nm range.
Well ...
Using the data @Higher Authority provided
(firstly had to change from absolute power to relative ,by dividing each y value with the largest of them,being the one at 604 nm )
and then using the calculator @alesh provided at the very first page of this thread (which BTW I think is very-very accurate ) I get
these values-calculated for the whole range of 380-780 nm :
LER : 332.77 lm/Watt rad
QER : 4.842 umol/Joule
PAR mult/ier : 0.01455 umol/sec/lm
...The PAR multiplier is spot-on with the " average" value of 0.0145 umol/sec/lm ,regarding the "average" 3000°K 80Ra pc-LED spectrum .
In few years in the near future ,when pc-LEDs at this particular "color " ( 3000°K 80Ra ) will have reached luminous efficiency of ~ 250 lm/watt ,
( more info : https://www.osti.gov/pages/servlets/purl/1421610 )
the practical max efficiency of ~75% will be the end of the road for the
3000°K 80Ra pc-LED used for horticultural artificial lighting .
That will be the upper efficiency limit for this type of LED tech .
So,it's about time that we take a closer look to the mono's ...
Never thought that I would state such a thing !
Using the data @Higher Authority provided
(firstly had to change from absolute power to relative ,by dividing each y value with the largest of them,being the one at 604 nm )
and then using the calculator @alesh provided at the very first page of this thread (which BTW I think is very-very accurate ) I get
these values-calculated for the whole range of 380-780 nm :
LER : 332.77 lm/Watt rad
QER : 4.842 umol/Joule
PAR mult/ier : 0.01455 umol/sec/lm
...The PAR multiplier is spot-on with the " average" value of 0.0145 umol/sec/lm ,regarding the "average" 3000°K 80Ra pc-LED spectrum .
In few years in the near future ,when pc-LEDs at this particular "color " ( 3000°K 80Ra ) will have reached luminous efficiency of ~ 250 lm/watt ,
( more info : https://www.osti.gov/pages/servlets/purl/1421610 )
the practical max efficiency of ~75% will be the end of the road for the
3000°K 80Ra pc-LED used for horticultural artificial lighting .
That will be the upper efficiency limit for this type of LED tech .
So,it's about time that we take a closer look to the mono's ...
Never thought that I would state such a thing !
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salmonetin
Well-Known Member
Airwalker16
Well-Known Member
This THEE OG SDS? StartDustSailor?
Airwalker16
Well-Known Member
Wow well it's an honor to have you back!More like the Restartdustsailor !
salmonetin
Well-Known Member
well im old and too poor some years in bed cost me too mucht phisically not have work and only few money
supervivency at limit but hey im on resistance all my life...you know
...thanks no covid in my house wife and family...uffff
my restart post...
My 2 Chance (Mi Regreso)
Hello bros, this time in short words im out by medical reasons, but its time to starting again... there are some friend mine here? seems to me im alone again... nothing new for me... Yes i know im not actualized, too many updates to come, i have a lot of new ideas for diy, and for commercial...
www.rollitup.org
...lot of new ideas... lot of new hardwares...but dont saw love here bro...
...too fast for me...i prefer erase my starting post on public side..
this time i prefer go on spanish my english is too bad...
now the blog idea its my only way...
but never knows