CFL question quick

[headshake]

fair enough, but i have, once again, myself, read on a box of (i think GE) 26W CFLs. it says it decreased the output by 20%!!!

next time i'm at the store i'll take a picture for you.

perhaps it is only certain models or something. not being rude!

-shake

headshake Reviewed by headshake on 04-04-2009. CFL question quick I have a simple question and im not even sure it if matters... When positioning your CFL's over the plants what way gives out the most light to the plant. straight up and down, or on its side, or maybe at a 45% angle? the space that it will be in will be lined with Mylar so i mean it will be reflecting all over the place but i just wanted to see if there was any real difference on how the lights put out light. Thanks for you time guys. Rating: 5

[stickyichy]

well i thought this was a pretty easy question but i guess it has a lot of mixed reviews. i think im going to tilt them at a 45%. The space i have is a small dresser that has been hallowed out and turned into a grow box. i'm very excited because a lot of the issues i ran into last time are now fixed.

The space will have fans that will push air in and out of the space. The lights are much more adjustable and evenly spaced, the space will allow for much more reflection of the light and i have even set up an automatic timer watering system so that i will not have to worry as much about the time i am away from it. Over all im excited. ill be starting a grow log when i start it all up.

[irydyum]

No sweat Shake. I'm just picky about evidence. So much on here is heresay and people preach things they aren't sure about, or have no evidence to support. I'm just doing my duty of trying to push people to look further into things, and to find EVIDENCE to support claims.

In no way am I trying to refute what you are saying, nor am I saying you are wrong. I just think it was short sighted to link a study that I don't think was read through enough. Once the ambient temperature was thrown into the mix it became too many variables for me, along with running the cfl's in enclosed luminairies and whatever else they did.

I just want something simple that says if you mount it this way the ballast is more efficient, or less efficient thus resulting in less light. You know, something like that.

It may be certain models or whatever, but I would think that the components of CFL's from home depot or wherever are so similar that the install specs would be the same for all of them. I'm off to do some research now.

[headshake]

make sure your fans have the same rating (CFM) since you will be using both active intakes and exhausts.

they need to have the same rating or it will cause the hot air to swirl inside your box (depending on your setup etc.).

intakes at the bottom and exhausts at the top.

good luck.

-shake

[headshake]

this doesn't answer the question specifically, but this could have to do with the answer as to if orientation has anything to do with output.

"This slow warm-up behavior is NOT common to all fluorescent
lamps. It is caused by the mercury amalgam used to control
mercury vapor pressure is most modern CFLs. Most linear
fluorescent lamps do not use an amalgam and will start at
50% to 60% of full output and quickly rise to 100% of full
output.

Some CFL manufacturers do not use amalgams and others have a
dual amalgam system. Either will provide a faster warm-up
cycle.


Why is the amalgam needed in CFLs but not linear lamps?


Because no part of a CFL is naturally cool enough to provide
the proper mercury temperature. Early CFLs had extensions
on the end of the tubes opposite the base called "cold
fingers". These extensions ran cooler than the main tube
because they did not have the hot discharge inside them.
Lamps that used cold fingers to control mercury pressure had
quicker warm-up than lamps that use amalgams. However, the
temperature of the cold fingers was different for base-up
and base-down operation, leading to differences in stable
light output for those two orientations. Since CFLs were
rated in base-up orientation, the cold fingers were
optimized for base-up operation. That meant that the light
output was lower when these CFLs were operated base down.
The US Federal Trade Commission eventually said that
manufacturers had to list both numbers (base-up and
base-down), or only the lower number, but they could not
list only the higher number. The amalgam was introduced as
a way to have equal performance for base-up and base-down
orientation."

-shake

[irydyum]

I'm sorry man, but I'm just not able to be quiet today. I'm going to quote straight out of the Medical Grow Bible (cervantes) here about setting up ventilation.

"(when using active intake) The ratio of 1:4, ie; 100 cfm intake fan, 400 cfm exhaust, should give the space a little negative pressure"

I know that negative pressure in your space is good, and positive is bad. If you have any positive pressure in the space, it will blow unwanted odors out through any crack in the space. If you have negative pressure, you are always containing your affected air, thus giving you the option to run it through a scrubber before expelling it.

I know this is for a smaller CFL grow, but the principles remain the same. Sorry again, but I still love you Shake.

[headshake]

The base-up alternative produces almost 100% of the rated light output. The light output from the base-down CFL decreases by -25% after a few minutes of operation. However, by adding a thermal bridge, the performance of the base-down CFL improves dramatically. (In all three cases, light output rises to 1.00 during the first few minutes.)

this chart is based on 15W CFLS.


-shake

[irydyum]

Can someone decypher Shake's last post into English? That explanation just confused me more than I was, I think...

Maybe it's the vape bags of Hempstar too, just can't be sure anymore.:stoned:

Just saw the little thumbnail you posted. That seems feasable but can u post the link u got it from, I just want to read the whole thing.

[irydyum]

Quoted from Rhizome in the Noobs guide to growroom setup sticky in basic growing.


Chapter the Second- Sizing your exhaust and intakes
OK- let's talk ventilation. The most important points here, IMHO-

-Nature abhors a vacuum- even a relative one ( or... pressures will tend to equalize)
-You're not moving air in, and you're not moving air out. You're moving air THROUGH.
-Questionable odors are probabley the #2 or #3 reason that folks get caught- ( Talking out of school would be #1).

The ventilation system is one of the most critical aspects of growroom design. I'm going to shy away from discussion of AC use for now- most personal gardens can get by without, and those that can't will generally be served by the climate control system of the dwelling. For now, we'll assume that that primary cooling/ dehumidification is going to be through exhaust.

The ventilation system, at it's simplest, consists of three elements- the intake, the exhaust, and the blower/fan. Choices here are about equivalently important. Let's start with fan sizing, which is tied to room size (in cubic feet) and choice of lamp.

For now, I'm going to assume that people are using a single main exhaust blower and a passive ( unpowered) intake. (Active intakes can be very effective, but great care must be taken to insure that intake CFM does not exceed exhaust CFM. In this case, you'll achieve a positive pressure condition in the growroom. This excess pressure WILL disperse in an uncontrollable manner, bringing with it delectable but dangerous aromas.( See above primary principles.) I would advise always trying to run at as close to nominal pressure as possible, with any variation from nominal being negative.)

Calculating cubic footage is simple- length x width x height = cubic volume. You want a main exhaust fan which can exchange the air in your room in no more than five minutes. I try to budget for three minutes. Let's comprimise at four minutes. Therefore, a 5x5 room with 8' ceilings would require a fan capable of [ 5(l) x 5(w) x 8(h)] = 200 cf. 200 cf / 4 (minutes)= 50 CFM for your fan. Doesn't sound like much, huh?

Now let's get into efficiency factor multipliers. ( This is where it all goes to hell).



Take your unloaded CFM requirement, and add 10 % for each foot of flexible ductwork that you are exhausting thru.( ie- you need to clear a 4x4x6 room thru 10' of ductwork. That's {96 CF /4 (minutes)}= 24 CFM + {(10'x10%)=100%} 24 CFM+100% (of 24 CFM)= 48 CFM. ( Exhaust loaded CFM)

Now take your (E.L.)CFM and multiply it by 1.5 for each 90 degree bend in your exhaust ductwork, cumulitively. ( Ie- you have a loaded CFM of 48 cfm that makes two 90' bends in it's ten foot length. That would be (48 x 1.5)x1.5- or 108 cfm loaded w/ bend factor.)

OK- CFM requirements are adding up pretty quick, and we haven't even talked about odor control. I personally think that carbon filters are the best method of odor control- but I figure that we'll get a healthy debate about this too. I like to put my carbon filter inside the room, near the ceiling. I like to set up the filter before the fan, so that air is sucked from the space, through the filter, through the fan, and then out of the space. This way, all air being pressurized by the fan has already been de-odorized. You can blow through the filter if you mount it after the fan, but be aware that between the fan and the filter there will be a zone of pressurized, stinky air- any leaks in your ductwork moving air from fan to filter will create potential smell issues. ( See primary principles above.)

Take your EL CFM ( including bend factor) and multiply by 1.3 to allow for intake restriction of the carbon filter. Don't forget to allow for ductwork between filter and fan!

So, if we're running a filter that's 3' away from the fan- our total duct length ( in the above example) is now 13'. Let's adjust our math.

We have a 4x4x6 room. Our total duct length is 13'. We're using a filter. Our math now looks like-

4x4x6 room= 96 CF. Divided by 4 minutes is 24 CFM required.
24 CFM + 130% ( 10%x13')= 55.2 CFM ( I'm gonna round to whole CFM, to try to minimize decimal over-runs)

(55CFMx1.5)x1.5= 124 CFM â?? to allow for our two 90 degree bends.

124 CFMx1.3 ( to allow for air velocity lost to the filter) = 161 CFM.

So we're looking at a 161 CFM fan.

But wait- we haven't even thought about how our light's going to effect this. We could go off into a discussion of determining system effeciency by measuring intake and exhaust temperatures so that we could calc differential temperatures, but I don't know how to make the little â?? deltaâ?� symbol on my laptop keyboard, so I'm gonna skip that and assign yet another load factor...

For a 250HPS- multiply by .75
For a 400- multiply by 1
For a 600, multiply by 1.3
For a K, multiply by 1.6.

(Let's be reasonable here- I know that my math falls apart if you're running a K in a 4x4x6 space â?? but is it reasonable to run a K in that space at all? In your very first room?)

So to put a 600 in that room, we'll take our base adjusted CFM and multiply by 1.3 .
161 CFM x 1.3 (lamp factor)= 209 CFM fan/blower to power the ventilation system.

I'm not going to blow out the math to establish what room intake sizes should be to prevent drag on the system- that get's WAY crazy... Instead, I'm going to propose that we use a rule of thumb stating that â?? Intake area should be fan CFM x .5 square inchesâ?�

Applying this rule, our 209 CFM fan would require an intake area of about 100 sq. inches- or 10â?� x10â?�. This does'nt have to be monolithic- two 50 sqâ?� intakes will work as well as one 100 sq â?? intake. You can check your intake sizing by just cracking open the door to the room and firing the fan- if the door moves at all, you need more intake.

When shopping for fans, round up- if you need a 209, and your choices are 180 or 240, grab the 240.

[headshake]

i think the chart came from this one:

IAEEL newsletter 2/93

here are a few more. i'm not arguing with you. i probably wouldn't believe it if i didn't read it the other day when looking at bulbs. it tripped me out. i think i said "what the f*ck" right in the middle of target. i hope one day to have a proper grow light where all of this won't matter anyway!

good growing.

-shake

EnergyManagerTraining.com
/pdf/LightOutputinCompactFluorescentLampinDifferentPosi tions.pdf

Fluorescent - linear, circular and U-shaped

Not Cool to be Hot

btech.lbl.gov/papers/37856.pdf

just google cfl output+orientation

glad to have you in the forums. i like good conversations!!!