Air cool 250w MH?

[capncrunchn420]

Im designing a new grow cabinet, Im going to be using the c24 Mills Pride cabinet. 6ft tall, 4ft wide, and 20in deep.

Its gonna be like a perpetual harvest ScrOG, every week I'll harvest a screen thats 10x10, the screens will be attatched to a 10x10x10 container, equal to 3 gal.

The veg part will hold only 4 of these containers, and the veg part will be 20x20x30, about 18in will be taken up vertically will be taken up by the container, and the height of the screen, leaving me with a foot left in the box.
The box will be vented by a 50cfm fan that would be capable of changing the air allmost 7x a minute.

Can a put a 250w MH light in this sized box without aircooling it?
Or would a small 6in oscilating fan do the trick of dispensing of the hot spot?

 

[capncrunchn420]

Or instead of a 250w MH, what about a 175w MH?

 

[Mackawber]

Can a put a 250w MH light in this sized box without aircooling it? Unless the outside air temps are 45 degrees or cooler, then no. You need intake and exhaust fans for that setup. Another reason you need intake/exhuast cooling vent capability is because plants like fresh air with CO2.

Or would a small 6in oscilating fan do the trick of dispensing of the hot spot?

Fans are better for circulating air and lessing the effect of radiant heat on plant surfaces. You still need fans for those purposes but you will need intake exhaust fans.

 

[capncrunchn420]

I decided to use the 175w MH instead, its cooler, cheaper to buy and operate, and still gives double the amount of light needed.

There will be exhaust, the 50cfm fan, and a passive intake system, so I'm pretty sure I have ventilation covered.
I still need a small fan in there any way to keep the air moving, so instead of going all out on an air cooled hood, and an extra fan to cool the hood (space is a concern of mine).
Just get either a small oscilating fan and aim it at the light, or a 4-6 inch axial fan and mount it onto the bat-wing reflector I plan on building so its allways blowing on the bulb, keeping it cool, and dispensing the heat around the whole box, which will then be vented back out of the box.

The bat-wing reflector won't take up hardly any space at all, so Im planning on allways having at least 8in between the bulb and the screen. And its only the veg. part of the box of my ScrOG so the foliage will allways be under the screen, with the exception of the occasional leave poking out.

 

[Guest]

sry to rain on your parade, but thats gonna get way too hot in there with only a 50 cfm fan and a 175w mH thats not aircooled. how about you use the 50cfm fan hooked up to ducting and a cooltube pulling clean air from outside the cab (sealed off ffrom the cab in other words) to cool your light and THEN maybe..............maaaaybe a second 50 cfm fan will pull enough air out to keep the space cool. This is assuming no carbon filter or anything.
again, not trying to be a jerk, thats just how it is. If you don't believe me then please do a dry run first just so you don't murder your babies in the heat

 

[clowntown]

If you're able to get a good amount of airflow in and out of the cabinet, I don't believe you'll need an air-cooled reflector. I ran my veg closet (20" x 40") with a 250w MH no problems, just needed to draw in the cooler (70F) air from the outside and exhaust the warm air out the top. I've also run that 250w in a CoolTube, and worked really well. Not sure how much light I was losing through the glass, but I could get the lights very close (touching the glass, pretty much) without any worries.

 

[mysticls]

if you have a digital 250w, they say digital puts out more than the standard 250w so this would make up for whatever lumens lost in a cooltube...

 

[Guest]

I have a hydrofarm 250MH with the ballast built into the top of the fixture,it would get hot in an enclosure but sure doesnt get hot in something like a small closet.You definately want to use some kind of cabinet though,I know you guys know what you're doing when it comes tocabinet grows and such,if it werent effective there wouldn't be so many folks doing it.Sometimes I just wonder though if you just growing a few plants.hell hang it in the middle of the room or maybe a closet or something instead of going through all the trouble of building/cooling/venting a cabinet like a c-34?Anyway,like I said there is something I'm missing obviously or you people wouldnt put so much effort into these cabs.I can understand if its a 50W sq ft dealie you're trying to achieve buy using an enclosure,but hell with a 250 and a few plants the fixture hanging just about anywhere should achieve about the same results.Dont you think?Or definately no.

 

[capncrunchn420]

Okay... Ive been looking at the space, and I think everyone was right, even with a 175w MH, in that sized area I'll need to air cool. I have a hurricane glass that I was thinking of turning into a DIY "cool tube", but the narrowest point is about 3 inches.

Will a standard 175w MH fit in there?
If it won't, and I have to buy a real cool tube, Im just gonna go ahead and get a complete 250w kit.

If I go aircool I'll probally use an additional 50cfm fan to aircool it that will draw air from outside the box from a room thats allways going to be 70-75 F.

 

[ElDust]

I don't air cool my 250w hps/mh and it doesn't get hot at all, I can still touch the glass.