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White cells: contain info needed to perform calculations. Dont change them (the sheet is unprotected and there is no hidden cells or macros; i let all the basic info displayed to allow anybody to upgrade the sheet).
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Green cells: headers of columns/rows/single cells. They say what are the info following it.
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Blue cells: they show calculated results
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Yellow cells: these are what you need to fill in to use the sheet.
The first row with the header "SPD of" is the tittle of the sheet. Fill in it with the lamp (manufacturer and model) to be analyzed (for example, Phillips SON-T Agro).
The most important info to fill in the sheet is the SPD (spectral power distribution) data. Its on the column B, below the final results. Ill post detailed instructions to get this data for yourself on the next message. For the moment, to learn to use the tool, copy one SPD from the "Hand Digitalizer Tool" wich has some of them saved. Paste it to the SPD column, starting below the green "SPD" header. If you want to keep the format of the sheet, use the "special paste" option by rightclicking the mouse, select only the "numbers" choice and disable the rest.
You can copy a full column in a single paste. You just need to click the first cell to be copied and move the cursor over the column up the final cell keeping the button pushed. Or by clicking the first cell and clicking the final one while pushing "SHIFT". All the cells get selected, rightclick and select "copy".
Once the SPD column has been filled, you have the results that only depends of the SPD. The spectral results are offered on the blue cells on the upper right corner. This data are fully independent of the model's wattage. They are, from up to bottom:
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LER (Luminous Efficacy of Radiation): figure given is how many lumen generates each PAR watt. The higher this figure, the more lm a lamp achieves for the same energy emission. Or the reverse, as higher LER, less energy (PAR watts) for each lm (or Klm=1000lm).
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PPF/Klm (Photosynthetic Photon Flux/1000lm): the figure correspond to how many micromols of photons holds 1000lm of that SPD. Its very useful to determine irradiance at top of plants, just by measuring with a light meter. The figure is the same for PPF/Klux, and lightmeters uses luxes (or footcandle; 1 fc=9.76 lux). So if you take a reading with a luxometer, divide reading by 1000 (3455 lx=3.455Klx, just put a .) and mutiplies it by the figure given in this cell, you obtain the irradiance in micromols of photons.
This method only work for unshaded areas. In shaded areas, spectrum has changed so you cant apply the PPF/Klm figure calculated for the SPD. But when possible, this way gives a irradiance figure without the need of using expensive quantum meters, and accuracy is very good.
Irradiance figure, or PPFD (PPF Density) on the technical literature, given in micromols of photons per second (abreviated, uE) per sq meter is the most relevant figure you want to know to improve your grow lighting.
PYF/PPF (wide) figure uses the full range 380-780nm instead of the standard PAR (400-700nm).
PYF (Photosynthetic Yield Flux) and PUR (Photosynthetic Usable Radiation) are two ways of estimating the ability of a number of photons to promote photosynthesis (plant growth). They are only aproximative, as plants adapt themselves to the light quality, so its impossible to use a universal valid conversion, as what is used to calculate lm for humans.
PYF is calculated weighting PPF by the McCree's curve after derating PPF for the average cannabis absorbance of photons at each wavelenght. Whyle PUR is calculated weighting PAR watts by the Inada's curve.
So PYF/Klm and PUR/Klm figures serves to calculate "plant lumens" from a luxmeter reading. While PYF/PPF and PUR/PAR Watts inform of how good is the spectrum alone for plants. The higher the figure, the better the spectrum.
Important note: In this context, "better" means more ability to promote plant growth. It dont inform about quality. This estimation are only useful on condition of low-medium irradiances. They arnt valid for saturated photosynthesis or CO2 limited conditions, found under high irradiances (what happen on most MJ grows, at least at canopy level), where qualitative analysis are required, as there is no studies about it.
R/B: Red to blue ratio. 4 or less correspond often to lights used in the vegetative, while over it correspond to flowering lights. Its given as ratio of uE or of PAR watts.
R/Fr: Red to far red ratio.
φ Pfr/Ptot: Phytocrome's photoestationary equilibrium. The higher the figure (max 0.89), the less stretching the light promotes, aswell as shorter but thicker leaves and some other biological effects (as effect on flowering induction and crop maturation). Lights with this figure below 0.75 promotes stretching. All lights used for growing have this figure bewteen 0.75-0.89. A good way to know if a spectrum isnt good for growing is when this figure is way below 0.75 (incandescents lamps are about 0.25).
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Blue, Green and Red percentages (of total PAR light). Its given both as percentage of photons (P) or PAR Watts (W). Names are simplified, as blue cover 400-500nm, green 500-600 and red 600-700.
PPF/PAR watt: uE that holds each PAR watt.
In order to analyze a concrete model, is required to fill in the data of that lamp. The sheet allows to calculate results for up to 12 differents lamps emiting same spectrum. In fluorescents, its pretty common to have a wide range of wattages and formats (T5, T8...) emiting same spectrum. This way you can see all in a single page, or compare how a different ballast or format affect results.
For each lamp to be analyzed, you need to fill the 6 yellow cells below the "wattage #" header, so you get its results below it. Data to fill in are:
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Nominal watts: watts of the lamp, 400, 600w, etc
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Actual watts: mostly, its the same than nominal, but not always. For example the Phillips SON T Agro 400w draws 430w actually. If you dont know actual watts, put the same than nominal.
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System watts:watts consumed for the bulb and its ballast (when required). The most accurate result from the sheet are obtained when this data is accurate, as there are wide differences between ballasts for same lamp. Precise data of ballast manufacturer are usually required to fill in this cell accuratelly. In case you dont know how many power lose your ballast, use a 15% (70-250w), 10% (400w) or 7% (600-1000w) of the power of the lamp. For example, a generic 400w HPS draw 400watts+ 10% of 400 (40watts)=440 watts. For floro ballasts, use a 10%.
Most data of the sheet are refered to system watts.
Klm (1000lm): lm emission of the bulb divided by 1000.
Price: optional info. If you want to compare how profitable are each option you are considering to purchase.
Useful Life: optional. Defined as time to reach 80% of initial emission, it allows to compare long term costs of different lamps.
If you let this last cell in blank, results associated to them are not shown (obviously). System watts and Klm are required.
Results are shown inmediatelly below. Bulb and system efficiency gives the percentaje of the burned power that is emited as PAR watts.
PPF, PUR and PYF are already explained. In this cells are shown figures of the lamp analyzed (corresponding data above).
Ratios per system watt (PPF/W...) gives it per each burned watts, so you can compare easily different wattage models perfomance.
Ratios per $ (or the currency you entered in the price yellow cell) gives them for each $ of initial cost. Price of each uE is the best measure of cost of a lamp.
Ratios per $ along the useful life of the bulb allows to analyze long term costs.
Heat load (of the bulb alone) or system Heat Load gives the amount of watts to be cooled. Any unit converter (you can use google directly for it) may covert it to cal or BTU or whatever unit you know of your AC system.
If something is not clear, just ask.
knna