Ventilation, connect several tents?

[KappaRoss]

Hey guys,

I am looking at the ventilation of my planned setup and am currently playing with the idea to set it up as follows:

120x120x185 (cm) veg tent which uses Fluorescents or CFLs gets passive intake from the room (the room itself gets passive intake from the adjacent room). At the top of the tent, it will exhaust the air through 2x 200mm diameter ducts. The ducts will then go down and be connected to the second tent (120x120x200) to become its intake. It is the flowering tent. In the top part of the flowering tent will be the carbon filter/scrubber which will either be connected to the fan within the tent or through 200mm diameter ducts to the fan outside of the tent. The fan will then be connected via ducting to the next room (different from intake room) or out a window.

I read over the "ventilation 101" thread and from it I could gather that when using 2 ducts to connect the veg tent and the flowering tent, while only having 1 final exhaust duct from the flowering tent, the pressure loss should be negligible.

The question is, what size fan/filter would I need?

For the 120x120x200 tent, I was going to go with a 750m³ fan and filter. I was going to generously oversize so I can dimm it and be equipped to deal with any and everything.

Now I am really hoping that I can stay on 750m³ for the fan, as this would mean I can use 200mm diameter ducting for everything and save myself a lot of time and headpain, as well as dinero.

If I have to go up to 1000m³ or higher, I will have to move to a 250 mm flange, which might well mean a bunch of headaches, at the very least though, different sized ducting tubes T_T

Since there is close to no temperature buildup in the veg tent, odor production will also be minimum... I am really hoping I can work with the 750m³ fan efficiently...


I also have the 3 40x40x80 tents that I would set up in the very same way, just 3 in a row and they all only have 1 intake and 1 outlet ... So pressure loss would be greater. On the other hand, I can put the cloning tent at the end of that row and the cloning tent really doesn't need much air circulation. The dry tent would be at the end and include a small filter. The utility tent would also be fine with this, depending on what I use it for. Otherwise it just gets pulled from the row and gets its own filter/fan...
The ducting would connect to the ducting from the flower-tent with a Y-connector and be exhausted from the room.

 

[KappaRoss]

I read in the meantime that professional breeders commonly use the exhausted air from the flowering room and use it as the intake air of their mother/clone areas.

The reason being that the air from the flowering tent is "pre-warmed" which is good for the mothers/clones who are often under fluorescents and don't have any considerable heat buildup in their area.

Add a bucket/bowl of water in there so the warm air from the flowering area will cause humidity levels to rise in the mother/clone area as well. From there it is exhausted out the window.



So what I am thinking of is definitely possible and probably even smart (although I had it a bit the wrong way around).
The question is what measurements/cfm/m³ I need with my areas...

And also if it is fine to combine the vegging area with the mother/clone area in this way or if the vegging plants would suffer under the warm air and higher humidity created this way (I think it would be good for them. Afaik only flowering plants need lower RH).


This in mind I would probably have a passive intake for the flowering tent, a filter/fan combo extracting that air, connected to the intake of the veg/mother/clone tent. It would have its own fan which exhausts out the window.

This way I would use 2 smaller inline fans (the one sucking air from the veg tent being a bit stronger than the one sucking air from the flowering tent) and a smaller carbon filter for the flowering tent...
The veg tent would probably do well with its own small carbon filter though since if any of the plants start stinking in veg, I would be exhausting that slightly stinky air out the window... not good.