Hi everyone, After trying to deal with temp issues from my cfls i finally broke down and purchased a 150w hps setup. Galaxy switchable ballast and cool tube with reflector. My question is how much cfm will i need to keep this thing cool? The intake for the cool tube will be from the outside of the box with exhaust also venting to outside. I will have a separate intake and exhaust just for venting the air inside of the box. Im doing this because i dont want to restrict exhaust airflow for the cool tube with a carbon filter. Would 2 40cfm pc fans(one on intake and one on exhaust) be enough for just the cool tube with a 150w hps? Thanks
150w hps cool tube cfm question
- Thread starter green4me2
- Start date
I dont want the setup to be really loud. Im sure a 150w hps doesnt throw off to much heat to require that size of a fan. I have read threads of people venting an entire grow room threw a cool tube with a 250w hps running a single 4inch 100cfm pc fan. I already have the 80mm 40cfm fans, i just dont want to build the ducting for those fans to find out they dont work, as i also dont want to order new fans when i might not need them. Does any one have an idea of how much airflow just the cool tube setup will need? As stated previously the air in the grow room will be vented separate from the cool tube.
dukeofbaja
New Member
I blow air over the 250 watter in my cool tube directly using a 80mm PC fan, but the cool tube connects to the rest of my exhaust, so slightly different.
But my bet is that 2 PC fans, both at 40 cfm or so, one as intake, one as exhaust, will generate enough cooling power to keep the cool tube cool to the touch with a 150 watt HPS inside it (even a 250). I would bet the farm on it
But my bet is that 2 PC fans, both at 40 cfm or so, one as intake, one as exhaust, will generate enough cooling power to keep the cool tube cool to the touch with a 150 watt HPS inside it (even a 250). I would bet the farm on it
Great! That makes things much easier and cheaper for me! Thanks for the help!!!
dukeofbaja
New Member
How long of a run are we talking about though? 5 ft? 10 ft? more?
I would say total travel from begining of the intake, threw the cool tube, and to the end of exhaust will be 30 inches raised all the way and when lowered probably between 40-45 inches.
dukeofbaja
New Member
No worries then. 4ft x (pi x r2) = 4ft x (3.14 x 4) = 48'' x 13'' = 4 cf (approx) within the tube (assuming your 4'' ducting). 4cf with a 40 cfm fan on each side, plus some resiatance from the light, the stuff that hangs it, the lenght of the run, and possible curves in the run when it is lowered, you will still exchange the air within the cool tube every 15-20 seconds or so. Not much heat can build up in that time.
Warning: the math in this post is rough and alcohol influenced, but should be conservatively estimayted, if anything.
Warning: the math in this post is rough and alcohol influenced, but should be conservatively estimayted, if anything.
Haha i like the warning! All your math looks good at glance. Once i get the setup running ill let you know how things go. Thanks again!
