The Best Ventilation Thread Ever

vostok

Trimmer
https://www.icmag.com/gallery/data/500/suggestedvent.JPG

The first thing is to provide ventilation for the plants living in the grow chamber.
The second is to remove the heap of heat generated from our lighting.

This chart gives some recommended ventilation rates for common applications.
I recommend 5 Minutes per Air Change and no more than 1-2 MpAC to keep stress down on the plants.

High airflow rates cause excessive dehydration which is hard on the plants.

https://www.icmag.com/gallery/data/500/SIMPLE_SCRUBBER.JPG
CFM = 3.16*Watts/deltaT
where deltaT = 10 *F

Intake Area = 2 x Exhaust Area
Fans - Axial/Computer Fans due to minimal pressure loss

Example: A 400 W HPS in a 3 x 3 x 4 cabinet needs 126 CFM of cooling for a 10*F temp rise above room temperature.
The 36 cu ft cabinet is ventilated at over 3 Air Changes Per Minute.

Pro:
Easy to build
Fans - axial

Con:
plants stink up the place
plants are stressed by too much airflow at 3 ACpM.
The plants only need 5 Minutes per Air Changes (MpAC). That's 0.2 Air Changes per Minute (ACpM).

For you hydro guys, this means more rez changes and nute swings because the plants will be drinking alot to keep
up with the dehydration caused by living in a wind tunnel.

https://www.icmag.com/gallery/data/500/SIMPLE_SCRUBBER.JPG
CFM = 3.16*(Total Watts)/deltaT
where deltaT = 10 *F

Intake Area = 2 x Exhaust Area
Fans - Blower or Inline for high pressure drop across scrubber

Example: A 400 W HPS in a 3 x 3 x 4 cabinet needs 126 CFM of cooling for a 10*F temp rise above room temperature.
The 36 cuft cabinet is ventilated at over 3 ACpM. The hard part is to match an oversized fan/scrubber combination to get the right airflow.

This design and the simple growbox have cooling requirements that exceed the ventilation requirements of the growchamber by at least 15x. Way too much stress on the plants by living in a wind tunnel.

Pros:
single fan design less equipment to purchase

Cons:
Fan operates at 50% or less airflow due to large pressure drop across scrubber
High SP requires a Centrifugal Blower, won't work with Axial fans
Fan/Filter Curves are needed to determine working airflow
Scrubber is many times larger than Ventilation specs to get light cooling airflow
many restrictions in multi chamber designs require special attention to intakes and intrachamber airflow
high airflow for to cool lights creates stress on plants
high airflow through scrubber reduces effectiveness
Centrifugal Blower and Inline Fans are very noisy 60-70 db

More Here: https://www.icmag.com/ic/showthread.php?t=112862

I've used this old advice many times
 
Top