does glass reduce lumen's by 30%?
- Thread starter greenduck
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Yea and what is the optimum temp for a bulb? Did you also know that if the bulb gets too hot it ruins the life of it? How exactly cold do you think the bulb gets in an aircooled tube? It sounds to me like you're guessing..
I don't understand your logic.. what do you mean a big radiator? Where do you think the heat goes? It just heats up the wing and then goes into the air from the hood? Then.. heats up the room. In addition, there are countless hoods that offer a better than "shitty footprint"
The huge advantage is that you can use air from OUTSIDE the room to expel the hot air outside the room without needing to filter or scrub it. It keeps the temp down and the need for less filters.
Sorry to pick on you man but you seem to have a strong opinion for someone without all the facts. And so you know, I do like the adjusta wing hoods and the like, but there is a solid place for BOTH styles. No sense in trash talking that in which you do not use or fully understand.
the optimum temperature for a bulb is normally specified by the manufacturer and is different for different types of lamps. It can be somewhere in the ranger of 400-700 Celsius so it is important. Some lamps really need a warm reflector and you do not need a lot of air to cool a lamp to its operating temperature. That's one of the biggest mistakes made I think: pumping too much air through a tube or reflector.
Though I would generally not recommend an air cooled reflector in some cases you have no choice. When you do it make sure you do it the right way.
Though I would generally not recommend an air cooled reflector in some cases you have no choice. When you do it make sure you do it the right way.
@St3ve
"I don't understand your logic.. what do you mean a big radiator? Where do you think the heat goes? It just heats up the wing and then goes into the air from the hood? Then.. heats up the room. In addition, there are countless hoods that offer a better than "shitty footprint" Thats the actual point !
Hello....what the F... are you talking about...Yes off course the heat rises from the AAW and is sucked out by the ventilation, that by most people, is located somewhere around the top of the growroom - Yes....Thats kind of the purpose, what I tried to explain was that you can get closer to your tops than you can with most big closed reflectors that often trap heat instead of radiating it off to the top. Point being if you want to get close to your crop you dont need a Cooltube with shitty footprint or dirty glass to diminish light. And a shitty footprint, is what you get with Cooltubes, no matter the reflectors, cause, you know the inverse law of light, Light goes from bulb to cool tubeglass to reflector....big loss compared to bulb - reflector - cause of the inverse law you loose a lot more. Do the math yourself choosing 8-10 % if you clean your tube at least weekly, lot less if you dont, then inverse that loss in the light actually hitting your crop...compare to a non glass open ended reflector....facit =
I dont feel "picked out" mostly because your line of thought is screwed. So you try to reduce the use of filters by lowering your light efficiency...strange. I guess you are filtering and changing your airsupply even with cooltubes - so what the gain using cooltube if you ventilate and filter the air anyway ? Why waste lumens ? Where would people get air from if not outside the growroom whats the point. So you get air form OUTSIDE through you cooltube and where does the air to ventilate your crop come from ? OUTSIDE, right, that where I get mine from aswell, just using one airmover not 2.
About the facts, does glass reduce light penetration - Yes. Even more if there is dirt on the glass, on the inside or outside, or both, plus the bulb - Yes.
Does it matter if you filter all you air in one filter or if you use 2 ventilators and only one filter no....only you have to buy another ventilator, whats the gain M8 ?, you use more electricity running 2 ventilators than one and you even lose lumens through the glass for what reason ?
I have a cool growroom without cooltube, cause I use the proper amount or airshifts and have the hot air efficiently rising to the top of the room and away form the bulb and then sucked out through the filter.
You have a cooltube with one ventilator, no filter, one ventilator with a filter...we have same temps, but I have more lumens than you, who is the more intelligent and smart one here ?
What facts do I miss out on ? That I use more filter than you for more lumens, yes and I would say thats the sensible way of doing it,
Cooltube is for Co2 growing IMO.
"I don't understand your logic.. what do you mean a big radiator? Where do you think the heat goes? It just heats up the wing and then goes into the air from the hood? Then.. heats up the room. In addition, there are countless hoods that offer a better than "shitty footprint" Thats the actual point !
Hello....what the F... are you talking about...Yes off course the heat rises from the AAW and is sucked out by the ventilation, that by most people, is located somewhere around the top of the growroom - Yes....Thats kind of the purpose, what I tried to explain was that you can get closer to your tops than you can with most big closed reflectors that often trap heat instead of radiating it off to the top. Point being if you want to get close to your crop you dont need a Cooltube with shitty footprint or dirty glass to diminish light. And a shitty footprint, is what you get with Cooltubes, no matter the reflectors, cause, you know the inverse law of light, Light goes from bulb to cool tubeglass to reflector....big loss compared to bulb - reflector - cause of the inverse law you loose a lot more. Do the math yourself choosing 8-10 % if you clean your tube at least weekly, lot less if you dont, then inverse that loss in the light actually hitting your crop...compare to a non glass open ended reflector....facit =
I dont feel "picked out" mostly because your line of thought is screwed. So you try to reduce the use of filters by lowering your light efficiency...strange. I guess you are filtering and changing your airsupply even with cooltubes - so what the gain using cooltube if you ventilate and filter the air anyway ? Why waste lumens ? Where would people get air from if not outside the growroom whats the point. So you get air form OUTSIDE through you cooltube and where does the air to ventilate your crop come from ? OUTSIDE, right, that where I get mine from aswell, just using one airmover not 2.
About the facts, does glass reduce light penetration - Yes. Even more if there is dirt on the glass, on the inside or outside, or both, plus the bulb - Yes.
Does it matter if you filter all you air in one filter or if you use 2 ventilators and only one filter no....only you have to buy another ventilator, whats the gain M8 ?, you use more electricity running 2 ventilators than one and you even lose lumens through the glass for what reason ?
I have a cool growroom without cooltube, cause I use the proper amount or airshifts and have the hot air efficiently rising to the top of the room and away form the bulb and then sucked out through the filter.
You have a cooltube with one ventilator, no filter, one ventilator with a filter...we have same temps, but I have more lumens than you, who is the more intelligent and smart one here ?
What facts do I miss out on ? That I use more filter than you for more lumens, yes and I would say thats the sensible way of doing it,
Cooltube is for Co2 growing IMO.
I don't think that the inverse square law has a lot to do with the inefficiency of cooltubes. The inverse square law defines the irradiation at a certain distance from a point source. If the light source is not a point source the inverse square law starts to work as 5 times the length of your light source, in HPS 50-90 cm from the source (depending on the size of the arc tube). Only then can you regard the HPS lamp as a point source and will it be read according to the inverse square law.
I see problems in cooltubes and reflectors but others than you see. A cooltube also has advantages.
Advantages cooltube:
- Efficient cooling and easy installation
- Light goes straight through the glass, not by an angle
- Good air stream around the bulb compared to a large air cooled fixture
Disadvantages cooltube:
- It's still glass which will cost you light
- Difficult to clean (and you need to)
- Not the best option in / with a reflector
About that last issue:
- An internal reflector can never have an optimal shape and is inefficient. It will also collect dirt in the air stream.
-With an external reflector some of the reflected light goes through the glass twice and some is even reflected twice.
Though the losses are there they are not a lot higher than when using a flat glass filter: much light is radiated directly from the lamp to the crop and most light will not go through the glass twice if the shape of the reflector is designed for a tube. But everything together, including the loss of output with certain lamps as they will run too cool, will have a profound effect on the available light. With that I agree. But for some different reasons.
@Whazzup. I was talking about the loss of light, reflected off the reflector, mounted on the cooltube. Even if the inverse square law does not apply within the first 50-90 cm, I am sure the 8-10% loss from the glass will result in significant less lightintensity from the light reflected off the reflector. Not counting the light that has to penetrate glass twice.
I am sure you can enlighten us as to the added light from a good reflector compared to no reflector at all, over a flat surface. Then, you logically have to subtract the 8-10% minimum from the whole added benefit of using a reflector in the first place + the 8-10% loss of the direct radiated light. All in all the total loss should be way more than 8-10% for a cooltube + reflector and thats under theorethical perfect conditions. When clean, that is, and way more when not cleaned properly. Also, you should still use a filter for the air going into the cooltube, unless you want to clean it all the time. Cleaning an airtube and bulb is time consuming and a pain IMO. I also think installation is everything but easy compared to hooking up a normal reflector and ventilation. Off course there are situations where it could be neccasary, but they are pretty rare the way I see it.
If a cooltube is needed, and you really want to effectively get rid of the heat, you really need to have a big diameter tube and tubings+ powerful blower, otherwise the heat will not be removed effectively. When removing all the hot air effectively, you will decrease the bulbs efficiency, due to to low temps, as you point out.
The way I see it, you either don't get rid of the hot air because of too little airflow or you do get rid of it, and loose efficiency of the bulb + the dirt/claening/loss of light from glass penetration/reflector as additional benefits. This is one of the dilemmas of cooltubes. They don't really work very good anyway you do it.
Interesting about the inverse law, from what you say, rather what I interpret from it, it sounds like it doesen't matter whether my reflector is 10cm or 50cm from my bulb since there is no loss, as the reflector is not the point source. I don't think I have quite gotten this part right. Could you pls elaborate in plain language Whazzup ?
Satyr
I am sure you can enlighten us as to the added light from a good reflector compared to no reflector at all, over a flat surface. Then, you logically have to subtract the 8-10% minimum from the whole added benefit of using a reflector in the first place + the 8-10% loss of the direct radiated light. All in all the total loss should be way more than 8-10% for a cooltube + reflector and thats under theorethical perfect conditions. When clean, that is, and way more when not cleaned properly. Also, you should still use a filter for the air going into the cooltube, unless you want to clean it all the time. Cleaning an airtube and bulb is time consuming and a pain IMO. I also think installation is everything but easy compared to hooking up a normal reflector and ventilation. Off course there are situations where it could be neccasary, but they are pretty rare the way I see it.
If a cooltube is needed, and you really want to effectively get rid of the heat, you really need to have a big diameter tube and tubings+ powerful blower, otherwise the heat will not be removed effectively. When removing all the hot air effectively, you will decrease the bulbs efficiency, due to to low temps, as you point out.
The way I see it, you either don't get rid of the hot air because of too little airflow or you do get rid of it, and loose efficiency of the bulb + the dirt/claening/loss of light from glass penetration/reflector as additional benefits. This is one of the dilemmas of cooltubes. They don't really work very good anyway you do it.
Interesting about the inverse law, from what you say, rather what I interpret from it, it sounds like it doesen't matter whether my reflector is 10cm or 50cm from my bulb since there is no loss, as the reflector is not the point source. I don't think I have quite gotten this part right. Could you pls elaborate in plain language Whazzup ?
Satyr
I don't use cool tubes. I feel they are only good growing vertically, and in the center of the grow where you are not reflecting light but surrounding the bulb. I'm referring to good aircooled hoods.
Where are you getting 8-10% lumen loss in glass? I have a light meter and have tested it and its nowhere NEAR what you are talking about. Barely over 2% in fact, which is MORE than made up for by bringing the hood 1" closer. And you keep talking about dirty glass.. if I scrub down the whole room every run, why wouldn't I take an extra 10 to clean the glass? Additionally, good air cooled hoods offer the same footprint as your wings, if not some a little better.
I run two fans, one that pulls fresh air through both rooms, and the other that turns off when the lights go off. The one with the filter is on 24/7 to keep negative pressure on the rooms so smell doesn't leak out. Larger filters don't work if you slow the fan down too much and now you are just buying much larger filters once or twice a year. Plus wasting electricity to keep the one larger fan running all the time.
You sound like you are a smart person, you are just commenting on stuff that you have no experience first hand with. Just because people are doing things in ways you haven't thought of doesn't make their ways wrong. It just makes you sound foolish when there are people like me on here that have actually done it and measured it and can prove you wrong with first hand data.
Peace
softyellowlight
Active member
simple steps
1) filter your hood's air intake with proper material.
2) clean your glass every 3-4 weeks. You'd be amazed at what a quick 5min wipe down will do. Keep the screwdriver (or whatever you use to get the glass out) IN the grow tent/box/room so that it's it's always right there.
1) filter your hood's air intake with proper material.
2) clean your glass every 3-4 weeks. You'd be amazed at what a quick 5min wipe down will do. Keep the screwdriver (or whatever you use to get the glass out) IN the grow tent/box/room so that it's it's always right there.
@St3ve....if we are talking vertical, its a different ballgame. Like I pointed out, there are applications for cooltubes, but, they are just not what the average joe are dealing with in an average setup like a flat grow in a tent/closet etc. If you don't have the height, OK, you could chance it, hoping the blower don't quit and you potentially have a firehazard, open grows yeah, but not much better than using a fan mounted beneath the bulb, from what I hear, I don't do vertical, so yeah on that part I agree with some ignorance, but otherwise, my shittalk about cooltubes stems from personal experience. In a normal setup its B.S. IMO the calculus don't add up. I cleaned the tube and the bulb at least weekly ! I still do that in a normal setup, and if you are remotely interested in optimizing your lightsource, you clean weekly, not in between your grows.
About the lumens lost through the glass, I don't doubt your findings, but I may doubt the quality of your equipment to make them. If whazzup says 8-10%, then I am pretty sure thats the figure, more or less. Thats based on a hunch that his equipment and other sources of knowledge far outreaches anyone else on these boards - by a lot.
I thought you'd lose more than 8-10% but I guess Whazzup talks about optimal lab conditions, not a dirty growroom with living plants and even insects at night,to smother the glass. Greasy fingerprints will even make it much worse and in general I bet that the dirt build up at most folks places will make it a lot of work to take apart the tube and the tubings and clean it weekly... Most don't waste the time, even on normal reflectors.
How much will you have lost at the end of a grow without cleaning - a lot, I think.
You get less light, bad footprint, need more cleaning, thats way more complicated and time consuming than usual. More time, less bud.
Satyr
About the lumens lost through the glass, I don't doubt your findings, but I may doubt the quality of your equipment to make them. If whazzup says 8-10%, then I am pretty sure thats the figure, more or less. Thats based on a hunch that his equipment and other sources of knowledge far outreaches anyone else on these boards - by a lot.
I thought you'd lose more than 8-10% but I guess Whazzup talks about optimal lab conditions, not a dirty growroom with living plants and even insects at night,to smother the glass. Greasy fingerprints will even make it much worse and in general I bet that the dirt build up at most folks places will make it a lot of work to take apart the tube and the tubings and clean it weekly... Most don't waste the time, even on normal reflectors.
How much will you have lost at the end of a grow without cleaning - a lot, I think.
You get less light, bad footprint, need more cleaning, thats way more complicated and time consuming than usual. More time, less bud.
Satyr
It is not that difficult to explain and not that difficult to calculate. Easiest is by explaining it with photons actually.
First of all the inverse square law doesn't completely work at short distance, I didn't say that there is no difference in light at a distance from the lamp. At long distances it does and that's what we use it together with electronic models of the lamp and reflector to calculate the irradiance and uniformity of a light plan.
We start with the total output of a lamp. Let's take the best lamp there is at the moment, the Philips GreenPower 1000W 400V double ended. It does >2000 µmol of photons per second in all directions (measure with Ulbricht Sphere). This is called the PPF (Photosynthetic Photon Flux)m and is measured in µmol/s photons between 400 and 700 nm (NOT according to a sensitivity curve!).
Now let's say we have a reflector that focuses all that light on a square meter and assume a 100% uniformity. When you measure the irradiance, the photosynthetic photon flux density (PPDF) you will read on your meter will be about about 1900 µmol/m2/s. Not 2000, because you have reflector losses. In the example you have 5% reflector losses. When you illuminate 2 m2 with the same light you will get a ppfd of 950 µmol/m2/s. When you overlap two lights 50% you again will have the 1900 µmol/m2/s. That is also how it works in a greenhouse: The lamps hang high but there are a lot of lamps and they overlap on the surface. You do not lose light. You just spread it over a bigger surface. Overlapping light you can add.
Another example: A plasma light outputs 300 µmol/s. On half a square meter you would have a PPFD of 600 µmol/m2/s.
As you see it is not about the distance, but the surface. Exactly like the inverse square law actually, but maybe from a different view that is easier to understand.
What is a good reflector? Let's talk some reflector design. First of all it needs to be built for the specific lamp so optically it is correct. The output angle you can design. One of the things you need to think about is the lamp operating temperature. The manufacturer always publishes that information for luminary manufacturers. In some cases we even use heat reflectors on the lamps to keep the electrodes warm! Typical lamp temperatures can vary (based on type od lamp and power) between about 400 and 700 Celsius. You reflector material should be suitable for that too.
Second important issue is the uniformity. Every reflector has a sweetspot where the direct and indirect light even out best.
An then of course you have the efficiency. The most efficient horticultural reflectors have a total efficiency (direct and indirect light!) of 96%!. These reflectors are either made of Miro aluminum and are easily replaceable (because reflectors get dirty and it is very hard to clean Miro without damaging it), as are the anodized reflectors. In horticulture we do not clean those, but after a certain period we re-anodize them. So they get a new reflecting layer.
Miro is most efficient though as a reflector material. Anodized reflectors don't get over 90%, most of the time much less and the are more sensitive to dust and dirt.
So before you start to jet cool your cooltube, consider what type of lamp you are using and if it is a good idea to cool it that much.
Air-cooled, not a cooltube, no sealing with tape, and EZ to clean dust
Air-cooled, not a cooltube, no sealing with tape, and EZ to clean dust
Here's a couple in a youtube demo video:
[youtube]ARiy5CxPPpg[/youtube]
FUCK taping your reflector up what a fucking pain in the ass and you end up never cleaning it lol. Wish they had these when I last air-cooled..
I like the LumenAire but concerned theres no alumabrite insert flap letting all that light go out the vent... Airflow ya ya ya, whatever, I want all my photons..
Air-cooled, not a cooltube, no sealing with tape, and EZ to clean dust
Here's a couple in a youtube demo video:
[youtube]ARiy5CxPPpg[/youtube]
FUCK taping your reflector up what a fucking pain in the ass and you end up never cleaning it lol. Wish they had these when I last air-cooled..
I like the LumenAire but concerned theres no alumabrite insert flap letting all that light go out the vent... Airflow ya ya ya, whatever, I want all my photons..
oh wow, there's a lot of information since i last view this thread. ill post some of my info soon. im hoping to really know what's the best hoods WITHOUT the glass on.
so, what are you guys using? is your room sealed? what's your total watts and btu's of cooling power assuming your room is sealed...
we have a room that's not sealed and we are trying to work that out so we can get co2 in there. ill probably make a post under the room design section and ill link it from here so you can see what im trying to workout. thanks
so, what are you guys using? is your room sealed? what's your total watts and btu's of cooling power assuming your room is sealed...
we have a room that's not sealed and we are trying to work that out so we can get co2 in there. ill probably make a post under the room design section and ill link it from here so you can see what im trying to workout. thanks
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187020
Oh and clean your fans homies ...
Oh and clean your fans homies ...
I dont use hoods or glass but even the bulb gets dusty... The little fan underneath gets so cruddy !! Fan cleaning is on my to do list now homies
Oh and clean your fans homies ...
I dont use hoods or glass but even the bulb gets dusty... The little fan underneath gets so cruddy !! Fan cleaning is on my to do list now homies
