Air cooled lights: the right way

Many of us use air cooled lights and lots of others have thought about trying them too. I wanted to address some points that will make this easy to do and more efficient if you have them already. The distance between the glass sheild and the plants can be as close as 3-4" with a 600 or 6-8 with a 1K. As you know as light travels it loses intensity, for every foot away from the light a loss of 25% or more! So using air cooled lights benefits both usable lumens, lower room heat and longer bulb life!
1. One thing that is most important is the fan used. It must big a large enough and durable one or it will be the weak link! For 250/400/600 watt lights a Dayton 265cfm is more than adequate to cool to a level where your hand can be right on the hood over the bulb without feeling any discomfort! With 1000 watters, they produce a lot of heat so a better brand fan or added cfms are a must. Elicent fans are in-line centrifugal and have a higher static pressure( amount of air moved in a given period of time) and will work best here. If you go with a Dayton 465 it won't cool enough to max your distances. Rather use an Elicent 200b it moves 636cfm!
2. The placement of the fan is very important to lower duct drag or friction caused with in the ducts lining. Solve this by moving or adding the fan right next to the light, this will move the most air quickly and reduce the temps the most. If you have, as I have seen, placed the fan 8+ feet away your fans effiency is less. So re-configure your fans set-up next time you adjust your light.
3.Keeping the glass very clean will help cut down on the lumen loss as microscopic dust particles reflect light back into the hood. If you are using Co2 you will need to seal the edges around the glass to prevent the gas and room odors from getting sucked into the light.
4. Bringing in the coolest intake air will aid in lowering the lights and rooms temperatures. You can take it from inside a wall that has access to air from under the dwelling. And for exhaust either insert it into a dryer/chimmney or vent into a room you wish to heat during winter. Four 1K's kept my whole house quite warm though mountain weather with temps in the teens!
5. Run an oscillating fan over the plant tops between the light and you can lower even further!
To sum it up you will have a sealed room with contollable temps, bigger yeilds and co2 usage down. Your cool intake air goes through your light and exits never having any odor or co2 added, and thats a good thing!

That is all very true, but one can drop about 3 to 5 degree's if they also insulate the out side of the hood, most noticeable temp change in summer heat.

I found the extra heat to be an added plus during winter as it help's keep a nice stable room temp.

On a sealed 400 watt system, closer than 5" gave bud's intensity burning, bud's turn white in color. The 600's I have also have a limit as how close they can get to the bud's, heat wise I can set them on the bud's if I wish, but light foot print decrease's as you lower the lamp on the grow, and again intensity light burn occur's on the bud's closest to the lamp, again I have found it to be with in 5" of the bud's, so in general my lamp's never get closer than 8" to the plant's as I like to keep a even foot print of light on the grow.

grow safe

realhigh.

A 4" duct can move only 120cfm of air flow in a 3 ft straight section tested, so if you use 4" duct, no reason for a fan larger than 140 cfm to cool a hood, just my opiniion about it.
6" is rated to move 200cfm of air flow thru a 3 ft straight section, and is being the recomended size duct to use for larger bulb's in sealed hood's, at least in my area.

Happy Holiday's to all.

realhigh good info on the duct rating, I never thought of that and it was never mentioned in any of the grow books that I have purchased. It may have been in there I just flash read. Thumbs up for the good info.

Stay Safe.

Mo,

The footprint is a matter of preference to each grow, and I definitely agree with you using the space most efficiently! The air flow is deceiving though, as I said static pressure is what the issue is, and not so much cfms. If you were to take a set of fans rated the same cfms; such as the Elicent 150a cfm rating 247 and the Dayton 265 cfm you would notice the lower rated fan (the Elicent)having much superior air pressure. It therefore moves more air quickly across the bulb giving lower temps. The newer hoods have larger duct openings to address the flow too, and an industrious type could enlarge the older 3" or 4" types. A great point you brought up! :wink:
realhigh; you are within the foot of distance to the bulb so you arent losing lumens as some, who must position their plants a greater distance away. A 24" distance = a loss of 50% lumens! :wink: But try out higher rated fans, ones with good static pressure before thinking a lower cfm would work the same. I have seen a much cooler room since I converted to better fans. The white tops are from "bud bleaching", when outdoors, plants get sometimes 15,000 lumens while indoors around 7250(with a hort 1k@ 20 sq ft) so light intensity isn't as much an issue as too much heat!

Yes, one should consider the drop in air flow in the routed duct's, caused by static pressure, so one can increase the size fan to compensate for this static pressure and still move the max amount of air the duct allow's. This in turn can bring a cooler hood.

It is also easy to increase the 4" duct to 6" duct, flange's for hood are available at most hydro place's, and use the same fan as before, but due to less static pressure, the fan can move more air, less static pressure to deal with, so in turn a cooler hood.

No matter what, if you do not supply the fan with enough air flow that it is rated for it is over worked and it will use more energy and wear out faster.

grow safe

Happy holiday's

realhigh.

great posts guys,
i'm sure that there many out there who will find this info quite helpful so kudos on the info and keep it coming fellas.

peace
beans

great info, just what i need for my new year project, converting 6 X 400watt HPS low bays by remoting the ballsts and adding glass and air cooling them. I have got some nice enclosures to put the ballasts into, i am going to use 2 x ballasts in each enclosure so i will have 3 x twin 400 watt ballasts, i will use a pc fan on the enclosures just to cool em a bit. I was thinking about even adding a relay and timer to the enclosure so they a ready to plug and grow. And( I know, never start a sentence with and) thanks to the generosity of BV, i will be able to show how i do it.
I was going to use a "kettle" connection plug to attach the lamp to ballasts, which is what mozst hoods use anyway, but i am wondering if any1 has suggestions of connectors which are more secure? such as my 1000 power plant ballas6t, has a metal clip which slips over the lead when plugged in to preven the lead being pulled out.something like this would be better, as each of these sets of 2, wilkl be on a lightrail 3.5 so need to be connected securely.

I have always liked the Hydrofarm connections as they are very secure and have a lip to prevent any moisture from shorting out your enterprise. You spoke of cooling the ballasts but not the fans for the lights themselves, which fan(s) do you intend to use?
Just make sure in your blueprints you include some slack for the line as movers with air-cooled is not as easy to iron out all the kinks at first! Allowing enough ducting for lower light heights is a factor. I dis-connect some hose as they grow taller to lessen the run, less duct drag. A good fan is not much more than a cheaper one but will benenfit you in the short and long run(immediate cooler temps and long life). Good luck and keep us posted on your progress!

I will be using centrifugal fans for the air cooling of the lights, i just got my TLC-direct catalogue dripped through the door, lol, u know, they guy at the grfow shop wanted to sell me a 6 inch centrifugal inline fan second hand for 80 quid, in this cataloogue, thats the price brand new, and i can get just abkoiut everything for a grow fro this cataloogue a lot cheaper.
For the cables connecting the hoods to the ballasts, i was thinking of using a plastic curtain rail alongside each lightrail with the cable, and the flexi-duct from the hoods, attached with those little plastic curtain hooks, thus allowing me to have just the right amount of slack, wiothout the leads and ducting being daragged back and forth atop the plants getting snagged, or trailing on the deck.

Sounds good! The tricky thing is to add enough flex-duct and not too much! I have sections that can be removed when it(the hood) gets highe. Do a dry run for a while to be certain of all connections and efficiency of the hose lengths. Most of us get fooled by cfms when deciding on fans. The cfms being equal we think the cheaper fan is the same, ahhh, but its not! The power or static pressure is what determines the force the air moves. The one with a higher force will remove more heat, although you are not in my neck of the woods, check out the time it takes to fill a large trash bag and compare if possible before buying. Brands with good pressure are Elicent and Hurricane, other fans local to your area will need to be checked or someone can add this info!

The brand is Manrose, MRK In-line centrifugal duct fans. I was also thinking about maybe using one of those acoustic fans, the box ones, as these are supposed to be very powerful and quiet too
I forgot to add, the manrose fans are the same centrifugal fans that the 2 local grow-shop stock. The nearest one and this catalogue also stock High prssure inline duct fans by soler and palau who make some great enviromental control equipment in industry too. There is a 5" high pressure inline duct fan runs at 350M3 an hour and can duct 7 metres in 5"duct.
As far as the dry run goes, that is a given, this is all for my big grow when i move in the new year. I will be getting it all working right before even 1 single clone enters the premises, lol.

Hey guys, I run a pretty similar setup to the one described in a loft. I have 6 x 600w (2 rows of 3) with a 750m3/h (per row) fan pulling air from one side of the loft, through the cooltubes and expelling it into another sealed section of the loft. I also have a seperate 750m3/h fan pulling the air out of the growroom and a passive intake.

I have the extractor fan on a speed controller and its at about half way at the moment, temps sit at about 25c max here in the UK as the winter has kicked right in.
Check out the pics for a better grip on what Iv'e done.

r those the cabinet tyope acoustic fans that i mentioned??

No Harry, they're just ordinary UFO style extractor fans that I boxed in using the candy floss type loft insulation and some polystyrene board. Does well cutting down on motor noise and vibrations. You can also cut down on the air noise from the exit of the fan if you ave longer ducting on the exit.

Good work Bramski! What are your temps?

They're sitting about 25C with the extractor fan on about half way. I think they'd go down to about 21-22C with it up full especially as the temps are freezing outside and I'm bringing in air via a stairwell window adjacent to the loft room.

tell me about my fan,

tell me about my fan,

I found this fan on ebay $20.00 (etri Anial fan 252.2 CFM mmh2o 0.83 inh2o 55.5 ) the description said it has a high air intake and low static presure. I noticed in the summer the temp didn't drop as much as I had hoped, but this is the first time I used ventelation. the fan is mounted in the attic and when the light is low it about 7 ft away. I now have a hood with a cool tube, but last summer I had a helmet shaped hood.



Any thoughts you guys have on this would be appriciated.

Now what I belive is being side about the fan's, is low static pressure mean's that the fan is rated setting in an open area, back area no obstruction's of air flow as the same on the front side, and if I a correct about my knowledge, low amp fan's are going to be low static pressure fan's.

High static pressure is coaused by obsticale's in the way preventing smooth easy air flow and there for the motor must work harder to move the same amount of air.

This would mean a higher amped motor as so it can with stand the drag on the air flow. So this fan will move more air when attacked to ducting or what not.

There is a mathmatical formula that allow's one to consider drag per foot and how long the run is to determine the size fan needed to aquire the desired amount of air flow one want's to keep.

The real key point is any fan can say it move's this much air and what not, but when put in the system and how we want to use it, well how much is it really moving?

Proper test equipment does allow one to figure it out, but not really available to the grower.

On average from what I have noted most all that have it working properly have at least a 10 degree drop in room temp., and yes it depend's on time of year and the temp of the incomming air supply to the hood's.

Spring, fall, and winter I use outside air comming into the hood's for this.
Summer time, does not help the temp's like it should, so I have a flange made up that take's A/C cooled air to the hood's during the cooking month's to maintain my room temp's via independently sealed hood's. I would like to get a controlled flange attached to this so that when room temp.'s do get to high, well it open's up and divert's the A/C air into the grow room until all is good, then close's and the hood's are getting it all.

This same elctro magnetic switch or silenoid on a flange attached to an A/C duct can operate and allow cool air into the grow room when needed, providing the A/C unit in the home is running, but if you want to put your brain to the test one can hook a thermo sensor to the most exsisting wall thermostat's and have it turn on the A/C to cool the grow room down, it will also cool the home more unless those other vent's are wired with on/off flow flange's and senosr's, but these can be wired to the home wall thermo stat and be controlled that way. When the sensor in the grow room turn's on the A/C, it send's signal to other open/closed flange's closeing them, so all cool air is into grow room, this could be way to much air, so not all vent's need to be equiped with such flange's. It can get complicated as one try's to control more, but it can be done if one want's to do it, it just take's money to get what is needed and some time to set it all up.

Good bud seem's to allow idea's to roll out, now to figure out is it a good one or a bad one.

stay safe.

realhigh.

Cough cough eer; your fan is under powered. You need to increase the pressure to acheive sufficient cooling, and locate the fan closer, next to the light, pulling the hot air off. The "fart" fan you're using is barely strong enough to remove those lol. Since you just had a B'DAy Congratulations! and go get a better fan!
Realhigh; you're on to something, as cooler intake air will greatly reduce temps. Your idea is very good and will work in hot summer months. And the static pressure is measured in an "open" space without restrictions like we have with lights, ducts and vents. So a higher pressure fan does the trick. I have several smaller low pressure fans but use them to cool the ballasts or rez surfaces. Some hydro stores have demo set-ups to check out the air-flow, Elicent models have one. These fans are the upper end of fans price wise so shop around, I bought a 1198 cfm one for 125.00usd on Ebay, a great fan but a larger than most need. Using a variable speed control will allow you to customize it to your space.

Thanks badmf and real high, I'm gonna put that on my list for santa claus. :smile: