How to exhaust veg & flower room with one ventilator?

[LEDman]

Hello everyone,

I am planning my grow room as seen in the picture (it's 2.5 x 5 meters in total). The air intake and exhaust CANNOT be moved or exchanged, these are the only places they can be.

Blue is for air intake (venting on ground level), the air stream supplies both rooms. Red is the exhaust fan near the ceiling.

I am having problems deciding how to move hot air from the veg room to the exhaust properly. My initial thought was to have a (light-shielded) small fan (shown in purple) near the ceiling between the veg and flower rooms, moving hot air from veg into flower, where a strong squirrel cage ventilator will draw it to the exhaust.

Do you think this setup is viable? I know I'm basically moving "spent" and warm air from veg to flower, but since it'll stay near the ceiling, that shouldn't create too much of a problem. I could of course string a flexible tube from the small inter-room fan to exhaust next to the squirrel cage... or shouldn't I? Any input is very much appreciated!

 

[bucktoothal]

Hello
The only problem I see with this setup is when the air from your veg. room comes into your flower room the humidity for your flower room will be raised and might cause problems with molds, and pest. a tube from you veg. room closer to the fan would help.

 

[PrairiePoet]

I didn't read Buck's answer, and was thinking the same thing.

For me, it is easier to add water to the air, than take it out. So I would swap the sides around. Intake outside into the Flower room, exhaust that into Veg.

Another thought would be to build separate systems. Intake feeds both side where needed, exhaust pulls from both sides. Exhausting the heat from the lights on the intake, would be a better choice than just dumping it into the other room.

shrug... great drawing!!

Prairie

 

[LEDman]

For me, it is easier to add water to the air, than take it out. So I would swap the sides around. Intake outside into the Flower room, exhaust that into Veg.

Actually, that makes a lot of sense, since increased humidity invites bud rot and whatnot.

I have amended my design accordingly - am I correct in assuming that in order to have an equal air flow, both warm air intakes should be about the same distance from the ventilator? Also, how powerful should the exhaust ventilator be in order to move enough air (the room's got about 31 cubic meters: 2,5 x 5 x 2,4m) and I'll be growing under 3x600W HID/HPS to start with. A rough estimate erring on the plus side would be awesome, as I have zero experience with moving that much air...

Thanks!

 

[PrairiePoet]

ok... on your intake, I would just come across straight into the other room. The less bends in the air passage the less drag, and more air flow. Then use diffusers to adjust how much air each room gets. Carefully watch so you don't put too much back pressure on the intake fan.

The exhaust should work. Keep in mind that you will want to directly exhaust light heat right into the exhaust system.

You've thought about odor control already, right?

Prairie

 

[LEDman]

Gotcha. Intake straight, exhaust straight, add diffusers. I don't have cool tubes at my disposal, I`ll be working with Adjust-a-Wings reflectors on my 3x600W instead. So, the question is: How much cfm will my exhaust ventilator need? The room's in the basement, so its ambient temperature will be low whatever the season.

I tend to over-engineer things, so I`d rather err on the side of caution with my exhaust setup.

 

[Pazuzu]

Here is another solution I concidered using to pull hot air from my veg cabinet into my flower cabinet, then through the carbon filter, cooled hood, the exhausted.
So there would be an added inline fan and this controller DS-100
HVACQuick - Suncourt Duct Booster Fans & DS100 Thermostat

But after playing with the size of the passive intakes I have it drawing through both cabinets and keeping them both a nice 76 degrees in my basement.

 

[LEDman]

Thanks, that`d be an option, too, BUT I think that adding an inline fan blowing hot air from the flower room would cause a positive pressure on the intake in the veg room, thus blowing into the veg room instead of to the exhaust ventilator.

I guess with my setup, one "sucking" exhaust fan should be enough for both rooms.

 

[Pazuzu]

yup ..I use one sucking exhaust fan for my two cabinets. The only reason I had concidered the previous option was if the veg room was getting too warm the thermostat in the duct in the veg room would kick it's fan on pushing into the flower room and then shutting off. Ofcourse the main exhaust fan would kick on according to the temp in the flower room thus which should pick up the veg room like intended also without creating positive pressure anywhere.
The above would greatly depend on the size of the grow room and would become more useful in a larger grow room of similar design.

 

[LEDman]

I see your point. Could you give me a rough estimate on how much cfm my exhaust would need to cope with 31 cubic meters total and 3x600W HPS? I know that there are more factors to take into account, but just a twinkling of an idea where to start at would be wonderful.

 

[mtlhead]

Just keep in mind that sizing of the intake and exhaust determines efficiency, how the air is handled once inside the specified area you send it where you want. I use formed sheetmetal ducting as my distribution hubs, then flex pipe to the desired locations. Search and find out how many c.f. of air you need to exchange for your total garden space and your golden, I presently run @ a 1.5x safety factor but also employ an environmental control system that regulates the conditions for me.

 

[SToRMz420]

Hi Everyone,

i have two 140x140x200 Grow Tents side by side, one for VEG other for Flowering,both with hydroponic systems setup, now the question is can i set-up one complete ventilation system that circulates through both tents??

The idea is to start in veg room the Enter Flower room then go into attic out roof...

1. what kind of ventilation system do i use just simple extractor fan, inline fan , carbon filter , ducting would that do the trick?

2. would i have to have one of the cool light setups where the ducting attaches to the light then out other side of light etc

3. im not sure what the cheapest most effective ventailtion products to buy any ideas suggestions on what to buy ?

any info on this subject would be amazing