Bends in ducting?

[SimplyM1tch]

ok so heres how i got it going carbon filter > hood > 4" ducting > 8" vortex fan > 8in ducting > 90* bend > 90* bend > outside

i know thats not good to have that many bends so im wondering how much cfm am i prolly loseing a big difference or small?

 

[mouthmeetsoap]

30% of your cfms are lost with every 90 degree bend, meaning you're losing about 60% of your cfms. No bueno mi amigo.

 

[SimplyM1tch]

30% of your cfms are lost with every 90 degree bend, meaning you're losing about 60% of your cfms. No bueno mi amigo.

Fuck....its doing the job of venting but its still getting hot in their hmm i might have to do some re routing

 

[Coals]

I would imagine its mostly your small 4" ducting. Theres no point in running an 8 inch fan down 4 inch ducting. You can only force so many cfm through a given duct size. If you search the web calulations for cfm and ducting are out there. As a general rule of thumb you want ducting the same diameter as your fan output or preferably bigger. With the 4 inch in front of the fan your choking the fan big time.

 

[SimplyM1tch]

yea I'm kinda stuck with the 4" ducting due to the fact that my tents holes are 4" but as for fans that 8" vortex is doing a dam good job at keeping my 1000w cool even with the size differance in ducting and the meny turns iv got going on

...I am all about efficiency and that definently is not but I don't want to start cutting holes in my tent ;( anyone got any thought comments or sugestion's?

 

[1mikej]

use long sweeping turns and you wont loose so much cfms

 

[gotdank]

I just made a calculator that may help solve your troubles - https://www.rollitup.org/do-yourself/383846-flash-grow-room-calculator.html

 

[SwiftGrow]

I agree that the 4" ducting and the 90 degree bend gotta go. Consider getting more ducting and bending less while taking a slightly longer path.

I run my 8 inch fan on 8 inch ducting that split into two 6 inch ducting for cool tubes.

 

[metrognome]

Are you using sheet metal ducting? Try flexible ducting!

 

[legallyflying]

All the CFM loss aside, your 8" fan is likely cooling your hood to the maximum amount. no? Is it warm to the touch? My current set-up is this.. Cool basement air intake..4' run > 90 > hood> 90 > 90> hood > 90 > 90> hood >90 > outside. and my 6" fan is keeping all 3 600 watt hoods cool to the touch.

Your tent is likely heating up from the actual light energy hitting the plants and the inside of the tent.. stick your hand under the light..see.

not sure what your doing for ventilation for the tent environment. I would buy a decent 4" fan, vent your hood with it and use the 8" fan mounted up high and connected to a thermostat switch to exhaust the tent when it gets to hot. Your going to need a couple passive inlet holes down low.

Hope this helps.