fans should pull air, not push.... their was a thread a while back, it said that the fan the way you have it laid out caused his bulbs to explode from vibrations and pressure... even if its not true other have said a fan works better pulling air...
i think your first set up would work because what is important is pulling air through the carbon filter and your first design did that. Also I wonder how much power are you are loosing on the 2nd design by having your fan pull through all that duct and hood before reaching the carbon filter. Go with the first m8 it's far more efficient.
no.... the second is better... another reason to pull air threw the air cooled hood is leaks... pushing air causes pressure and will cause leaks in the hood... this has been discussed at length in several threads... the second is better... both will work, but you always pull, not push... the fan has a easier time of pulling rather than pushing, it will also last longer...
Pulling air from the chamber like that has been known to caused seriously reduced bulb life, or even explosions as tihspeed said. Has to do with the humidity and turbulance. Post this in the lighting section, youll get better opinions there. I would suggest two seperate fans man.
The second one is the only way to go. It will be much more effocient, save on bulb and fan life as well.
I do have a medium sized growtent(3x3x6) with a cooltubed 400w HPS. I have two inline fans. My setup is this: Duct-->Cooltube-->Inline fan exhausting out the window Carbon Filter-->Duct-->Inline fan exhausting out the window Having two separate fans is more efficient at keeping temps down. If you have cool intake(about 60-65F)i believe you could pull it out with one fan.
I don't get it, maybe I don't understand this whole carbon filter procedure. To me the carbon filter serves to filter the air so it comes out smelling good on the othe side. Shouldn't the cabon filter be on the other end of your diagram? It makes no sense to me to have the carbon filter on that side of the fan like in your diagram. I would like to use a carbon filter myself, but not exacly sure where it should go in my growroom, and I have seen other diagrams similar to yours, which makes me think I don't get it at all. JV420, are you venting out of the room? Please enlighten me?
The reason its not on the other end is because that kind of filter is meant for air to be "pulled" thru it not "pushed" .
PROFILTER carbon filters can go both ways ,you can push and suck trough them... Do the search online for more information if you are interested .