Grow Room Improving tent environmental conditions and efficiency.

[WildBill]

With a new bunch of testing girls coming up, I want to make low/no cost improvements.
I'm still not super happy with my current tent set up. I think I should be able to run cooler tent temps with my exhaust fan speed setting with the setting of my portable a/c.
My A/C is to the left of my tent blowing straight out. I have the left bottom vent in the center of my Gorilla 4x4 tent as the passive intake. My 8inch carbon filter and exhaust are in the rear with it exhausting out the right rear on the top. I have two mid-pole mounted oscillating fans pointing down on the right-rear and left-front poles.
I can get the temps where I really want it, but with higher exhaust fan speeds. That screws with my humidity levels. Both seem to have run at higher levels to get what I want.

Nothing is automated. The automatic setting on the humidifier is not really as reliable as I like, it usually stays on manual and I monitor the level and change it on my phone. The temps aren't really high 82*F is the max. Setting on the a/c is 73*F in a 900sq/ft room A/C is 14K/10K btu/hr single pipe. Exhaust tube is wrapped for less heat imparted to the room.

How stable would some sort of external venting attached to the tent and ran next to the A/C air flow with positioning it not to be forced into the tent, but using the exhaust fan to draw it into the tent?

Now, if that's viable, what intake to use o the left side? The next run will be with an EarthBox with 3gal pots on the other side. With the above set up, I can make the transition and use the current rectangular intake. The box would diffuse the intake flow well.
Easier would be using the bottom front intake on the left-hand side. That would give the longest path for air flow and I think I can place my humidifier in the front center for a good mix of the vapor.

I can throw some money at this and do some automation and upgrades, but that's not in the plans with the possibility of a bigger grow later down the line. Like in drag racing, I want to fully maximize my current set up before spending more on power increases.

Opinions?

 

[CannabisMingus]

How stable would some sort of external venting attached to the tent and ran next to the A/C air flow with positioning it not to be forced into the tent, but using the exhaust fan to draw it into the tent?

I will defer to the more experienced, but I'm not sure what gains you would be getting. I may have missed it but is your humidifier on a controller?

 

[WildBill]

I will defer to the more experienced, but I'm not sure what gains you would be getting. I may have missed it but is your humidifier on a controller?

No. it's a box store ultrasonic humidifier that I can control with my phone and can turn on a set rate or automatic with self monitoring. Auto mode is not as consistent as I'd like,.

IF I can get the intake closer to the output of the a/c, I could run the exhaust at a lower speed and run the humidifier at a lower rate and still maintain the temp and humidity I want.

Stability is a must with any set up.

 

[CannabisMingus]

My experience with most consumer humidifiers is that the built in humidistat is usually way off. I use an Inkbird controller ($40) that gets pretty close as compared against a NIST-traceable hygrometer (=/-2% either way) and that has helped when dialing in the Cloudline T6. The problem with this method as it limits your choices on a humidifier. Need one with a knob, not a digital control. HTH, IMHO, YMMV, etc.

As to the question, I think the only answer is try it and see - it may work!

 

[pop22]

I think using an intake fan would do what your looking to do. Use another 8" for intake but run slower than your exhaust to create negative pressure, you'll get better airflow through the tent. And remember, accurate RH in a tent with multiple fans running is not likely unless you measure from several spots and average it. Even in something as small as a tent has micro climates and the fact that we try to get circular airflow in a square box... If your trying to control VPD, look to keep it to a range, not an exact or narrow figure, plants just aren't that fussy, only we are lol!

With a new bunch of testing girls coming up, I want to make low/no cost improvements.
I'm still not super happy with my current tent set up. I think I should be able to run cooler tent temps with my exhaust fan speed setting with the setting of my portable a/c.
My A/C is to the left of my tent blowing straight out. I have the left bottom vent in the center of my Gorilla 4x4 tent as the passive intake. My 8inch carbon filter and exhaust are in the rear with it exhausting out the right rear on the top. I have two mid-pole mounted oscillating fans pointing down on the right-rear and left-front poles.
I can get the temps where I really want it, but with higher exhaust fan speeds. That screws with my humidity levels. Both seem to have run at higher levels to get what I want.

Nothing is automated. The automatic setting on the humidifier is not really as reliable as I like, it usually stays on manual and I monitor the level and change it on my phone. The temps aren't really high 82*F is the max. Setting on the a/c is 73*F in a 900sq/ft room A/C is 14K/10K btu/hr single pipe. Exhaust tube is wrapped for less heat imparted to the room.

How stable would some sort of external venting attached to the tent and ran next to the A/C air flow with positioning it not to be forced into the tent, but using the exhaust fan to draw it into the tent?

Now, if that's viable, what intake to use o the left side? The next run will be with an EarthBox with 3gal pots on the other side. With the above set up, I can make the transition and use the current rectangular intake. The box would diffuse the intake flow well.
Easier would be using the bottom front intake on the left-hand side. That would give the longest path for air flow and I think I can place my humidifier in the front center for a good mix of the vapor.

I can throw some money at this and do some automation and upgrades, but that's not in the plans with the possibility of a bigger grow later down the line. Like in drag racing, I want to fully maximize my current set up before spending more on power increases.

Opinions?

 

[Bruce Campbell]

I can get the temps where I really want it, but with higher exhaust fan speeds. That screws with my humidity levels. Both seem to have run at higher levels to get what I want.

It sounds like you're temperature-limited, exhausting the tent to the lung room (i.e., not outside), have an A/C unit in the lung room that then vents outside, and you're considering if providing air for the tent intake directly from (or closer to) the A/C cold outlet will improve things?

 

[WildBill]

I think using an intake fan would do what your looking to do. Use another 8" for intake but run slower than your exhaust to create negative pressure, you'll get better airflow through the tent. And remember, accurate RH in a tent with multiple fans running is not likely unless you measure from several spots and average it. Even in something as small as a tent has micro climates and the fact that we try to get circular airflow in a square box... If your trying to control VPD, look to keep it to a range, not an exact or narrow figure, plants just aren't that fussy, only we are lol!

I learned a hard lesson on microclimates this run. I created one that was very prime for one and pure doody caacaa for all the others!
I'm trying to keep from adding a load to the room. I'm pretty close. I think I can swap an outlet from the adjoining room from another circuit. but I haven't tested it.
KISS is a good philosophy. I think I'll try the simplest and cheapest(nothing) and run a hose from the bottom left front tent outlet to close to the outlet of the A/C. I have the hose and Gorilla duct tape.

I'll play with that for a few days and take readings with my monitor in several; places. Maybe we can get some interesting data on air flow

 

[WildBill]

It sounds like you're temperature-limited, exhausting the tent to the lung room (i.e., not outside), have an A/C unit in the lung room that then vents outside, and you're considering if providing air for the tent intake directly from (or closer to) the A/C cold outlet will improve things?

It's not really temp limited. The losses from exhaust of the A/C heating the room air has been minimized with insulation, as well the window adaptor. Yeah, it draws air into the lung room, but that's conditioned air. The exhaust from the tent is out the top rear and directed towards the entrance of the room, away from the window. I think air circ in the lung room is about as good as it could be, given the room and type of a/c unit.

Yup, easiest is what I'll try first. I'm just going to make the cooler air is available to the inlet hose and not forced into it. I'd lose more control over it if it were forced. The exhaust fan couldn't throttle the temps that way near as much. At least the way it works in my head.

 

[Imagine]

I ran into much the same problem. If I ran the fan fast enough to keep the temp down, my rh was way to low. I moved a ac vent directly below my air intake. I can cover/uncover the vent to get a little added tweak if I need it and I added a pan of water inside the intake with a humidifier wick standing in it to add a little extra humidity. Not perfect but it helps. Keeps my temps at 79° and 60% rh lights on.

 

[YoungGrassh0pper]

I think using an intake fan would do what your looking to do. Use another 8" for intake but run slower than your exhaust to create negative pressure, you'll get better airflow through the tent. And remember, accurate RH in a tent with multiple fans running is not likely unless you measure from several spots and average it. Even in something as small as a tent has micro climates and the fact that we try to get circular airflow in a square box... If your trying to control VPD, look to keep it to a range, not an exact or narrow figure, plants just aren't that fussy, only we are lol!

Wouldn't a booster duct fan work for an intake, he going to run it lower than the exhaust anyway. That was my plan for my 3x3.