Air Cool Cmh Bulbs?

[heisen]

I just got off the phone with growers house and they don't have a t9 bummer but the staff I spoke with said the t12 will work in a air cooled hood. I know with the extra glass I won't get the full benefits of the light spectrum. Time to dig around my shed for my old none vented old school 600 watt hoods.

thats where i ordered from and the guy told me i couldnt.that it wouldnt run right

 

[DemonTrich]

T12 can be ran open or enclosed hoods. Do NOT operate a t9 in an open hood. It doesn't have the safet 2nd glass jacket.

 

[PharmHand]

Air cooled hoods with glass are super inefficient no matter what kind of light it is. Your losing a minimum of 10% light even with perfectly clean glass, and ALL of your short wave UV light. That's not including the light/spectrum you lose by physically cooling the bulb, that's hard to say exactly it would depend how much you cool it. Then you have the ducting holes in your reflector. You'd of course lose more with an 8" than a 6" but two duct holes occupy a significant portion of your reflector. Get a little dust on your glass, more lost still. I'm not saying it won't work it's just a significant waste. If you weigh what it wastes vs cooling benefit you are further ahead running 30% fewer lights with a split ac cuz that's probably what you lose. One look at Demons garden will tell you it can work well- he crushes it with AC hoods.... But would do even better without the glass :) Peace

 

[heisen]

Yeah a 10 percent loss in light ain't worth the heat stress to my plants.my plants like a nice cannopy temp.also I might lose a little light bUT the extra cost in electricity to cool open hoods ain't worth the neglible weight I might lose.
I'm OK with air cooled hoods.I'm just trying to move the heat away.
Also it seems to me if the room temp is 76 than with an open hood it would be cooling the bulb with colder air instead of removing excess heat with outside air.if u had 12 for ceilings and a 50,000 btu ac than I would probably go that way

 

[PharmHand]

And I think it's recommended all MH be in an enclosed fixture or double jacketed now because of risk of explosion. I've had a regg mh blow up on me sending hot shrapnel everywhere all over my room, luckily no fire tho and thankfully I wasn't in there at the time. But with the CMH explosion could be more serious cuz it runs hotter and at higher pressure. If you look at the old CMH allstarts the arc sphere was wrapped with wire to contain a potential explosion but they seemed to have done away with it when they brought out the double jackets and enclosed only bulbs. I've been researching the crap outta these lights I'm just about to help a friend setup a CMH flower room...... Tunnel like rows of cmh adjust a wings with LED inter lighting, it should be epic lol

 

[PharmHand]

It's more like 30%. Like I said add it up you're further ahead electrical efficiency wise running less light with an ac. That's why you don't see commercial guys running ac hoods it doesn't make sense. It obvious you didn't read what I said I'm not gonna waste my time any more.... Peace

 

[heisen]

yeah man commercial is just that commercial.You can hang a DE gravita 12 feet up and wont get the heat right over your cannopy.There are plenty of fans and big BTUs to cool the room.But for someone with 7 foot cielings and has to get the bulbs closer to the plants i cant see how open non air cooled hoods would be better.
And in theory light reduces its PAR drastically for every foot.So if im losing 30 percent at 24 inches i can air cool the hoods and get in another foot and get back the lost light.
If air cooled hoods didnt have there place in the industry no one would use them.
A 1000W HPS puts off alot of heat.when i kick my fan off that hood heats up to ungodly amounts.
Air cooled hoods have there place in tents and smaller areas.In a big open room i would go open fixtures all the way

 

[Pimples]

Yeah a 10 percent loss in light ain't worth the heat stress to my plants.my plants like a nice cannopy temp.also I might lose a little light bUT the extra cost in electricity to cool open hoods ain't worth the neglible weight I might lose.
I'm OK with air cooled hoods.I'm just trying to move the heat away.
Also it seems to me if the room temp is 76 than with an open hood it would be cooling the bulb with colder air instead of removing excess heat with outside air.if u had 12 for ceilings and a 50,000 btu ac than I would probably go that way

With mogul socket Hid lamps....its not a defined 10% loss. It depends on how dirty the glass gets (use filters on the intake side) and how cold that intake air is. But it is about 4 to 5% loss just from clean glass. Many feel as you do that the light loss is a fair tradeoff for the extra air conditioning required especially in the warmer months. Lets be real here...when air cooled hoods werw all the rage for years..people were still cropping out some awesome crops. If air cooled hoods werw that horrible people would of ditched them along time ago. In my opinion (i sold mine a couple years ago) have a purpose still. Especially that smaller grower with jusr a light or 3 that doesnt want to get spendy on a.c. If you duct them bitches right..with the right fans...air cooled hoods remove ALOT of the heat. Its a trade off really.

 

[PharmHand]

yeah man commercial is just that commercial.You can hang a DE gravita 12 feet up and wont get the heat right over your cannopy.There are plenty of fans and big BTUs to cool the room.But for someone with 7 foot cielings and has to get the bulbs closer to the plants i cant see how open non air cooled hoods would be better.
And in theory light reduces its PAR drastically for every foot.So if im losing 30 percent at 24 inches i can air cool the hoods and get in another foot and get back the lost light.
If air cooled hoods didnt have there place in the industry no one would use them.
A 1000W HPS puts off alot of heat.when i kick my fan off that hood heats up to ungodly amounts.
Air cooled hoods have there place in tents and smaller areas.In a big open room i would go open fixtures all the way

Whatever works for ya man. I thought you were talking multiple lights, I apologize.... When you move your light up you don't actually lose light, it just spreads out,according to the inverse square law. But when you have multiple lights that just means more light overlap less shade angles more penetration as a result. The good thing about cmh is it makes less infrared heat in relation to usable light so you require less cooling. A simple intake exhaust should do the trick. Another drawback to ac hoods is for the most part it's the light itself that raises the temps. The light itself raises the temp of everything it reflects of off, that's why you lose light even on reflective surfaces because some of that light is absorbed as heat reflecting the rest. That's why you still need to cool an ac hood room. Just seems so redundant. I used to run AC hoods many years ago my yield went way up when I switched out my hoods to just cheap bat wings. Good luck to ya in whatever you decide. Happy growing :)

 

[Pimples]

It's more like 30%. Like I said add it up you're further ahead electrical efficiency wise running less light with an ac. That's why you don't see commercial guys running ac hoods it doesn't make sense. It obvious you didn't read what I said I'm not gonna waste my time any more.... Peace

That would be some dirty ass glass and super cold air for a 30 % loss. Its not that bad. But in general aircooled hoods arent ideal...especially for larger growrooms.

 

[Pimples]

I too ditched my a.c. hoods years ago. I also went to a true sealed room with a split/dehuey and consistent co2. My yields went up...big time. But i attribute this to all of these factors. D.E. lamps and sealed room being the main ones. I also got aggressive with my canopy training methods. Double ended lamps and a nice even canopy with a ton of flowering sites....one or two nice ones per net trellis square go great together. Lol

 

[heisen]

Yeah if i had 10 foot ceilings and a couple mini splits i would go open all day long,But i cant be stacking up no 800 dollar light bills so some of us have to keep it simple,and get the most out 13,000 BTU air conditioners.

 

[Pimples]

Yeah if i had 10 foot ceilings and a couple mini splits i would go open all day long,But i cant be stacking up no 800 dollar light bills so some of us have to keep it simple,and get the most out 13,000 BTU air conditioners.
Thats where air cooled hoods fit in perfectly.

 

[PharmHand]

http://glassproperties.com/reflection/
So at least 8% to start. Plus even a micro film of dust at least 1-2%. 6-8" duct holes x 2 would occupy 5-10%+ of your reflective surface. Plus cooling the bulb itself is huge losses can exceed 10% np plus change the spectrum. Can't forget about the UV- gone.....Hugely important to me
This is a topic that's been beaten to death in many many forums.... I won't push it too hard, the infos out there if youre truly interested. I get it, not everyone's as anal as me and everyone has different goals but if you wanna get the most bang for your buck figure out a way to ditch the glass. Sorry if I ruffled any feathers I really am just trying to help, save people from having to research the hell out of everything the way I do. Peace

 

[MIMedGrower]

It works like that for all bulbs.... if you want the most photons to hit the plant.... You bare bulb it. It just so happens glass really reflects your narrow light waves. Stuff close to your blues and ultraviolets

Better reflectors have tempered glass which does not block it as much.

My metal halide in a glass enclosed blockbuster lamp still tints my uv tinting glasses.

 

[MIMedGrower]

When the bulb blew was it like an electrical explosion or does the ceramic explode?
What makes the explosion worse than a mh blowing out?

Cmh burns hotter and at higher pressure than mh.

And I believe it was an off brand single jacketed bulb reported exploded. Not a double jacket Phillips.

 

[Pimples]

http://glassproperties.com/reflection/
So at least 8% to start. Plus even a micro film of dust at least 1-2%. 6-8" duct holes x 2 would occupy 5-10%+ of your reflective surface. Plus cooling the bulb itself is huge losses can exceed 10% np plus change the spectrum. Can't forget about the UV- gone.....Hugely important to me
This is a topic that's been beaten to death in many many forums.... I won't push it too hard, the infos out there if youre truly interested. I get it, not everyone's as anal as me and everyone has different goals but if you wanna get the most bang for your buck figure out a way to ditch the glass. Sorry if I ruffled any feathers I really am just trying to help, save people from having to research the hell out of everything the way I do. Peace

Naw homie. You aint ruffled shit. Its good. Its what these forums arw for. Just your numbers are a little off with light loss and air cooled hoods. Actually its dependent on how dirty the glass is and how cold the intake is. I have a digital footcandle meter. And a newly acquired PAR meter that kicks ass but i never used it on a.c. hoods.. The most i ever lost with my old air cooled hoods was roughly 6 or 7 % in lumens. Granted i kept my hoods glass clean and didnt take in outside air. Just cool basement crawl space air. But your right. Any loss is not good considering your paying for the electricity the same. But its a trade off with electrical consumption on a.c. With multiple air cooled lamps in the warm months you will prolly need a.c. anywAys. Just not near as much if you cool them hoods right. Straight as possible duct runs. Insulated duct and hood blankets (very underrated and helps big time) along with placing hood duct fans outside the actual grpw room. (Along with ballasts if you can help it ) help alot. Many factors in determining if air cooled hoods are right for a grower and particular set up.

 

[MIMedGrower]

Air cooled hoods with glass are super inefficient no matter what kind of light it is. Your losing a minimum of 10% light even with perfectly clean glass, and ALL of your short wave UV light. That's not including the light/spectrum you lose by physically cooling the bulb, that's hard to say exactly it would depend how much you cool it. Then you have the ducting holes in your reflector. You'd of course lose more with an 8" than a 6" but two duct holes occupy a significant portion of your reflector. Get a little dust on your glass, more lost still. I'm not saying it won't work it's just a significant waste. If you weigh what it wastes vs cooling benefit you are further ahead running 30% fewer lights with a split ac cuz that's probably what you lose. One look at Demons garden will tell you it can work well- he crushes it with AC hoods.... But would do even better without the glass :) Peace

You are forgetting that an air cooled hood can be run closer to the plants actually increasing the amount of photons to the canopy.

Demon can get his cmh to 12". I can't seem to get closer than 16" open and vertical.

But uv is compromised. And the Phillips bulb I use is meant for vertical mounting for best par.

 

[heisen]

You are forgetting that an air cooled hood can be run closer to the plants actually increasing the amount of photons to the canopy.

Demon can get his cmh to 12". I can't seem to get closer than 16" open and vertical.

But uv is compromised. And the Phillips bulb I use is meant for vertical mounting for best par.

thats what i was saying earlier.i also think the glass used in them hoods is a better quality than just regular glass

 

[Freshone]

Pharm hand is on the money,if you are air cooling your lights you are losing at least 10% to glass(any glass) and by cooling your bulb you are changing the spectrum losing even more.Take your bulbs out of air cooled hoods and you will see a big bump in yield and plant vigor.