Lighting efficiencies

So I am working on some calculations related to various lighting stats. I am using a common lamp for starters. Eye Hortilux Super HPS 1000 watts


Eye Hortilux
LU1000B/HTL/EN

Wattage (Actual)
1000
Initial Luminous Flux (lm)
145000
Luminous Efficiency (lm/W)
145
Color Temperature (K)
2100
PAR (umol/s) @ ? Cm
1798
PAR WATTS
535
Photo Flux (phyto-lm)
290000
Photosynthetic Photon Flux
PhRUE
Lifespan (hours, optimal)
10000
CRI
26
The value in question is the PAR value quanta of 1798
Assuming PAR=micromoles/m2/s
(at an unknown? distance from light, assumes an optimal distance?)

To convert for an HPS light source to PAR WATTs the formula should be 1798/5 (according to K.J. McCree. Photsynthetically Active Radiation)
Which = 359.6
Not the value presented on some spec pages, and presumably the side of the lamps box. Which is 535. A considerable discrepancy, either in the conversion formula or the way they are expressing PAR Watts. (W/m2)
Funny thing is if I take the energy efficiency of the light (assuming an efficiency of 36.5% of your actual lamp wattage) you get 365. A LOT closer to the formula above, so where is the 535 coming from?

The efficiency/loss numbers are taken from the actual lamp wattage and the PAR wattage stated (535/1000=53.5%, plus 10% for the ballast overhead). If the 535 number is wrong to begin with there is an added issue. But basically I am saying 63.5% of your energy is lost to heat, giving you a 36.5% efficiency.
The conversion is talking about the entire 400-700nm range, rather than a specific wavelength.
Another interesting thing is that most of the PAR sensors out there just measure that range seemingly without weighting specific wavelengths, which seems the point of the PAR meter to begin with. So how can a PAR meter reading give you a real plant response rating without calculating a bias on certain peak ranges (red, blue); as more relevant than say green/yellow? The sensors do not appear to care as long as the energy is within the 400-700 range. Also, the li-Cor sensors are the closest to ideal with fewest errors, overestimates and has best cutoffs for UV/IR. Perhasp there is an inner coefficient that I am unaware of that the instrument uses to bias certain wavelengths, dunno.

My point on the last comment is that a PAR measure off a CFL 2700K would be exaggerated as most of the energy is in the human eye response range, not the plants. I digress and don't want to debate lighting sources, just the measure of them.

I have no data for the following
Photosynthetic Photon Flux
PhRUE

Cheers

You are correct there is a major problem with the 535 PAR watts claim. 600 and 1000 watt HPS lamps are up to 40% efficient when they are brand new in terms of PAR watts and visible spectrum.

Regarding the ballast, I tested my 600w digital ballast for total power consumption. It starts of at ~400 watts and after a minute or so bumps up to full power ~660 watts. The ballast is about 90% efficient so the bulb itself dissipates about 600 watts.

So in the case of a brand new 1000w HPS with remote digital ballast, we get 400 PAR watts in the grow room and 600 watts of heat.

All of our choices for lighting technology have about the same amount of ballast losses. The best electronic ballasts for PLL fluoro and HPS are 90% efficient with great power factors and the best LED drivers are about 90% as well. Unfortunately it is more common to see 78-80% efficient ballasts in LED builds (including my own) and with poor power factors. Compact fluoro ballasts have poor efficiency and a poor power factor and those losses are included in their specs, which is part of the reason they perform so poorly compared to their tube counterparts.

So I am working on some calculations related to various lighting stats.

Click to expand...

Fun stuff. You might find the technical comparisons which begin on page 6 with formulas on page 8 helpful @ http://www.inda-gro.com/pdf/MeasuringPlantLight.pdf

Perhasp there is an inner coefficient that I am unaware of that the instrument uses to bias certain wavelengths, dunno.

Click to expand...

nope

Mr Flux if you are interested, could you run this data through your magic process to estimate PAR watts and radiometric efficiency?

145000 lumens
1000 watts


higher res SPD

The PAR figure started by horticulture lamps(the 1798µmols) is PPF. PPF is the total light that the lamp puts...regardless of distance. They measure it in an integrated sphere. No light is lost or not accounted for because it's in a sphere and all sides are sensing the photons. Technically the bulb it's self blocks some light, but the sphere size they use is based on the size of the source(bulb) so that it doesn't block too much light and the reading is deemed valid.

The number that uses a distance from the source is PPFD. The "D" is for density. PPFD is dependent on distance and escaping light not hitting the sensor. This is basically the field measurement for how much of the possible light is directed/received by your canopy.

We lighting nerds are all dreaming of a "photosynthesis meter" that would take into account plants needs like a lumen meter does for us humans. But the problem is that even though it is fairly clear what the peaks are...the rest of the spectrums importance is still highly debated.

You nailed it GG. As you can see op "lighting efficiencies" is a complex and incompletely understood subject especially when we start comparing one lighting technology to another. Here a few observations I have made that I believe are objective and repeatable.

-HPS buds will get you high just fine and is a cheap and simple approach.
-Adding 450nm blue visibly increases trichomes and noticeably increases terpenes. Potency is more subjective but I suspect that is increased also.
-LED wastes less light due to directional output and can more than double HPS in terms of grams/watt if high efficiency emitters are used and run soft and cool.

I know you are not looking to debate lighting technology and there is no doubt LED and HPS work great together.

Thanks for the summary. I think I get it now.

Greengenes707 said:

The PAR figure started by horticulture lamps(the 1798µmols) is PPF. PPF is the total light that the lamp puts...regardless of distance. They measure it in an integrated sphere. No light is lost or not accounted for because it's in a sphere and all sides are sensing the photons. Technically the bulb it's self blocks some light, but the sphere size they use is based on the size of the source(bulb) so that it doesn't block too much light and the reading is deemed valid.

The number that uses a distance from the source is PPFD. The "D" is for density. PPFD is dependent on distance and escaping light not hitting the sensor. This is basically the field measurement for how much of the possible light is directed/received by your canopy.

We lighting nerds are all dreaming of a "photosynthesis meter" that would take into account plants needs like a lumen meter does for us humans. But the problem is that even though it is fairly clear what the peaks are...the rest of the spectrums importance is still highly debated.

Click to expand...

PAR is normally quantified as µmol photons m[SUP]-2[/SUP]s[SUP]-1[/SUP], which is a measure of the photosynthetic photon flux (area) density, or PPFD
So what is a PPF measure? (what is, not what does)
In an integrated sphere, my impression was they were calibrated to measure luminous flux, typically, and that ultimately it depends on the sensor being used, not the sphere itself, in terms of what is to be measured. Flux inherently requires a measure of area, correct?

http://www.labsphere.com/uploads/technical-guides/a-guide-to-integrating-sphere-theory-and-applications.pdf
3.1 radiometers and photometers
An integrating sphere combined with a photodetector of the appropriate spectral response can be used to directly measure the total geometric flux emanating from a light source or the flux density of an illuminated area. The geometric distribution of the light to be measured determines the appropriate integrating sphere design. The spectral properties of the light source determines the appropriate photodetection system.

If I understand correctly, PPF is simply a measure of total photons emitted per second but you make a great point flux implies a unit of area. So that makes PPF and PPFD the same thing. The unit of area is worked into micromoles definition too. Looking into this more.

I guess if you wanted to measure actual photons you would use quanta. Must be the integrating sphere estimates the total photons that hit its surface each second and converts that to a meter2 based on its own surface area. So they are taking three steps at once, total photons, per time per area.

PAR watts convert PPF into watts by taking into account the variable energy of photons of different wavelengths and adds it all up. For example, even though blue photons are more energetic they don't drive any more photosynthesis than red photons, therefore red being more efficient.

also found this illuminating
http://envsupport.licor.com/docs/TechNote126.pdf

and after reading this, I think I see whats going on.
http://www.inda-gro.com/pdf/MeasuringPlantLight.pdf

next question:
Photo Flux (phyto-lm)
290000

Anyone wanna tackle that spec?

canadian1969 said:

PAR is normally quantified as µmol photons m[SUP]-2[/SUP]s[SUP]-1[/SUP], which is a measure of the photosynthetic photon flux (area) density, or PPFD
So what is a PPF measure? (what is, not what does)
In an integrated sphere, my impression was they were calibrated to measure luminous flux, typically, and that ultimately it depends on the sensor being used, not the sphere itself, in terms of what is to be measured. Flux inherently requires a measure of area, correct?

Click to expand...

I told you what PPF measures, and what the differences are between both(PPF and PPFD)...but let's go further.

They both are expressed with µmols which makes it a little confusing probably

PPF is measured in µmols/s...meaning the lamp puts out "X" µmols of photons per second...and for a hps(and most sources) they go every direction basically.

Where all those emitted photons(the PPF) fall/go in space after they are emitted is the PPFD...measured in µmols/s/m^2.

This picture above is for the inverse square law, but it shows how light intensity changes over distance because of it spreading out, and that it all came from the same PPF. And you can notice that the area surfaces in the pic are slightly curved because they are only part of the whole sphere that is actually emitted. The source emits a constant amount of photons(the PPF) and as the spread the "density" is lost over distance because of the omni direction of a normal bulb like source(and light in general for he most part). But the amount that was emitted at the source(ppf) is fixed/constant.

LED's are a directional light source and don't waste much light in comparison to traditional sources, and thus they can have lower PPF's, but equal or better PPFD readings than omni directional lights. So not only are led's actually more efficient in true light conversion, but also in light that can actually hit your canopy(less stray light). And then with focusing lenses,, they collimate the light to a certain extent, limiting the spreading out of the light. Led's with lenses actually don't follow the inverse square law because they are slightly collimated.

To go a step further for a visual to think about...a laser's PPF and PPFD are basically the same because it's 100% collimated and the light is literally all going straight out and not spreading at all from the source.


Read this, maybe gavita's words will sink in better

From Gavita's Website said:

Plants primarily use the light ranging from 400-700 nm bandwidth (violet to far red). The light within this bandwidth is called Photosynthetic Active Radiation (PAR). So the bandwidth of the light that plants are sensitive to is much broader than what we see. Using lumens, which are measured according to what the eye is sensitive to, is therefore not a correct representation of the grow light properties of a lamp.Photons

Scientists proved that there is a relationship between the number of photons and the photosynthesis: It takes about 8 - 10 photons to bind one CO2 molecule. They also discovered that there is little difference in the effectiveness of blue or red light. So there is a direct relationship between the number of photons in the PAR spectrum and the photosynthetic potential of a plant (and ultimately the yield of a plant).
For many years now professional researchers have used photon counts in the PAR spectrum as a standard and the greenhouse industry followed very quickly. Most European horticultural lamp manufacturers specify the output of their lamps in PAR photons per second. Because photons come in large numbers we uses a multiplier, in this case Avogadro's constant (6,0221415 × 10[SUP]23[/SUP]) to get an expression in mol. 1 mol photons is 6.0221415 × 10[SUP]23 [/SUP]photons. Now that's a lot of photons and to get that to levels that become easier to comprehend they are divided by 1 million, thus creating micro-moles (µmol). So 1 µmol is 6.0221415 × 10[SUP]17 [/SUP]photons.
To illustrate why µmol work a lot better for us: the PPF of a 600W HPS lamp is about 1100 µmol/second. If you would express that in moles it would be 0,0011 mol/s. Now that's a bit more difficult to calculate with.
Photosynthetic Photon Flux (PPF)

Photons are counted per second as we count a flow or flux of photons. If you count all the photons that a lamp emits in the PAR spectrum per second you get the Photosynthetic Photon Flux (PPF). The only way you can measure this accurately is in an integrating sphere, the Ulbricht sphere. So the PPF is measured in µmol/s and represents all the photons in the range of 400-700 nm per second. But how much ot that will reach your plant and at what distance?

Photosynthetic Photon Flux Density (PPFD)

Let's say we mount the lamp in a really good horticultural reflector, which has a total efficiency of 95%. That figure means that of the original 100% light of the lamp, 95% is totally emitted by direct light from the lamp or reflected light from the reflector. You could also say your reflector losses are 5%. Now if you spread your 1100-5% on a surface of 1 square meter, you would irradiate 1045 µmol/m[SUP]2[/SUP]/s (1045 µmol m[SUP]-2[/SUP] s[SUP]-1[/SUP]). This is called the Photosynthetic Photon Flux Density. If I would move closer to the source and would just light half a square meter the irradiance would be 2090 µmol m[SUP]-2[/SUP] s[SUP]-1[/SUP]. And of course spread over 4 m[SUP]3[/SUP] you would get 261 µmol m[SUP]-2[/SUP] s[SUP]-1[/SUP]. Double the surface means half the PPFD. Just divide the PPF by the lit surface in m[SUP]2[/SUP]to get close to the calculated PPFD. You will always have some stray light losses (much more with open reflectors!) and you have influence by the reflection of the walls, which causes a loss.
PPFD you can easily measure with a quantum meter and a sensor that is specifically designed for the PAR spectrum. Unfortunately real quantum meters are expensive. The Li-Cor meters are used throughout the industry and are recommended. Most meters under $500 use lumens sensors and an internal table to approximate the PPFD in micromoles. We have found them to be inaccurate because they are still more sensitive to certain colors and do not take other colors within the PAR spectrum into equal account.
And how about spectrum?

PPF and PPFD only qualify the amount of photons, and not the quality of the spectrum. If spectrum was not important you would be able to grow any plant under just a single color red LED for example. Plants need different colors for different processes. The color of the light specifically influences the shape, build and development speed of the plant. In greenhouses the sunlight provides quality light. The HPS lamps are just used for extra photons, for quantity. So yes, spectrum is important, specifically when growing indoors where there is no sunlight. Plants have developed under sunlight for millions of years so you can expect them to be adapted for that spectrum and they use all of it as efficient as possible.
Calculating with micromoles

If you know how much light you require for optimal growth of your plants it is easy to calculate how much lamps you need. There is one complicating factor, and that is walls. Walls reflect only part of the light, as low as 40-50% depending on the reflective material. When using diffuse reflection materials not all of the light reflected will reach your crop. So there are serious losses at the edges of your grow room. The bigger the grow room, the less the wall effects. One way to solve the problem is to keep your final fixtures closer to the wall than half the distance between fixtures in the room to allow for some more direct light and reflection at the sides to even out the overlap. An adjustable reflector that sends the light down at the wall side can save you a lot of light.
When you have a room with many lights you will have a great advantage when you overlap your light. Hanging your lamps higher from the crop will create a bigger spread and a lower PPFD per fixture, but you can add the overlap from the other lights so you will still have the same light on your crop but at a greater distance. This is much easier for climate control and a more uniform light coming from different directions, enabling a better penetration in your crop.
Roughly these are a few examples of recommendations for a high light recipe of around 700 µmol m[SUP]-2[/SUP] s[SUP]-1.[/SUP] Calculations made with 10% reflector / wall losses:
400W [SUP]a)[/SUP] - 1 x 1 m - 1 m[SUP]2 [/SUP]at a ppfd of ~ 650 µmol m[SUP]-2[/SUP] s[SUP]-1[/SUP]
600W [SUP]b)[/SUP] - 1,2 x 1,2 m - 1,44 m[SUP]2 [/SUP]at a ppfd of ~ 690 µmol m[SUP]-2[/SUP] s[SUP]-1[/SUP]
1000W [SUP]c)[/SUP] - 1,5 x 1,5 m - 2,25 m[SUP]2 [/SUP]at a ppfd of ~800 µmol m[SUP]-2[/SUP] s[SUP]-1[/SUP]
In practice levels can be lower with different reflectors (open reflectors will have more stray light), older reflectors and a lot of wall influences. Other lamps may result in different densities.
[SUP]a) - Philips GreenPower 400W 230V - ppf 725 µmol
b) - Philips GreenPower 600W 230V - ppf 1100 µmol
c) - Philips GreenPower 1000W 400V Electronic - ppf 2000 µmol[/SUP]

Click to expand...

If that is hard to read here is the link
http://www.gavita-holland.com/index.php/item/lumens-are-for-humans.html

Took me so long to write and edit the post above, you guys figured it out already


A note on quantum meters(incorrectly referred to as PAR meters...I still call it a par meter all the time)

Licores are the most trusted in the horti-world, but even they have some degree of error...but it's damn close for practical purposes and measuring the light that is at the canopy to make sure it is with in the plants requirement range.

A specroradiometer will measure the intensity of each nm separately and that is why they tend to read higher than hand held quantum meters(licore, apogee, hydrofarms). There is not as much error because they can treat/measure each nm how it needs to be.

Pulled this right from the quantum sensor specsheet
The SQ series sensors are quantum sensors designed for use with dataloggers. Photosynthesis is driven by the number of photons between 400 and 700 nanometers (nm). This is called the Photosynthetic Photon Flux (PPF) and is measured in μmol m-2 s-1 (micromols of photons per square meter per second). PPF sensors are commonly called quantum sensors because a quantum refers to the amount of energy carried by a photon. Line quantum sensors are often used to quantify the variable light in greenhouses and below plant canopies because they provide a spatial average. An innovative blue lens improves the accuracy of these sensors, filtering incoming light for an improved spectral response.

Hense my confusion, glad to know PPF and PPFD are different, I think.

I can see why you are/were confused. There is few questionable/wrong things stated there.

What sensor is that from???

EDIT:
Found it. I have the apogee myself. And have meet the owner personally. Surprised that is up there like that. Look around and what I gave you and google some more. Should get more clear.

A note on units: Visible wavelengths of sunlight can be represented as either a quantum flux or a radiant energy flux. Quantum flux is regarded here as synonymous with 'photon irradiance' (Q) and has units of µmol quanta m[SUP]-2[/SUP] s[SUP]-1[/SUP] ('µmol quanta' rather than 'µmol photons' because the quantum energy derived from photons drives photosynthesis). For the sake of making a clear distinction from quantum flux, radiant energy flux is simplified to 'irradiance', and for present purposes, irradiance coincides with photosynthetically active radiation (PAR). Irradiance is then expressed as joules (J) per square metere per unit time. Depending on the application, time can span seconds, days or years, and is then coupled with either joules, megajoules (MJ) or gigajoules (GJ)
(Based on Gates 1965)

sorry, just a copy paste for reference, not making any points
Seems to me if you are just measuring micromoles per second, this is a power measurement. where the flux measure requires the defined area. Not trying to piss anyone off, seriously, just that something isn't quite right. Like I cannot find a single spec sheet that illustrates a PAR calculation other than ɥm/m2/s1

http://5e.plantphys.net/article.php?ch=t&id=131
Even here, I cannot find a distinction from PPF and PPFD. I hear what you are all saying...

When you think about it, an integrating sphere will measure the same amount of photons per second regardless of the size of the sphere. But PPF does take surface area into consideration because as you pointed out flux does. So think of the integrating sphere as a meter2 canopy wrapped around the bulb.

PPFD does the exact same thing except it is referring to a meter2 of actual canopy. So yes they are basically the same thing

Guys, I would be VERY interested to see what is published spec wise on the side of one of your HPS lamp boxes, any make/model, doesnt matter.
Up here we have different laws, not sure if there is a diff in what they have to report. Pretty sure you have the FCC telling them what has to be given spec wise.

You might be onto something. I saw a post that stated: Eye does not publish anything but lumen data. The specs on their site do not mention par watts.

You are on to something. For a grow lamp mfg. the spec should be in PPF not lumens. If you look at the first chart we show radiant PAR watts as a single number representative of lamp efficiency between 400-700 nm. This is not good enough as the regions are too broad to five us anything of value insofar as what it means to photosynthetic response curves. So we broke it down into the three regions of photosynthetic response. You are then able to determine lamp output any of the 5 metrics used in the technical comparisons within those 3 Vegetative Carotenoid and Flowering regions.

PPFD does the exact same thing except it is referring to a meter2 of actual canopy. So yes they are basically the same thing

Click to expand...

You make the distinction then finish with 'they are basically the same'. They are very different. In the link I provided on page 11 it describes those differences in detail. You will take PPFD with a li-cor- apogee,... handheld meter which defines the intensity based on area. Even with the exact same lamp and number of hours this measurement will vary wildly depending upon fixture/reflector designs. The PPFD measurement is an in situ measurement, that is that accounts for the fixture/reflector/area that a PPF value does not. And this is why when I see a lamp mfg or a sensor mfg issue values in PPFD I know the confusion as to their different meanings exists within the industry and certainly confusing to those who are not in the industry and are simply trying to determine a lamps value based on their best interpretation of these values prior to purchase.

So how would one measure PPF? Can we work out a conversion or some math based on the hortilux bulb, assuming most of the numbers are accurate. Which numbers are PPF versus PPFD?