Regarding dialing in the environment. My room is 10x12' with 7' 2" or so ceilings. The basement room is new construction: three stick walls with drywall, one "outside" cement wall. Ceiling and inside walls all are heavily insulated. Currently in Flower (8 plants in 7 gal., day 40 of 12/12) with 700w LEDs of actual draw. 6" Vortex fan with controller and filter. Thin walled 6" PVC exhaust pipe runs 15' in a straight line to a window (removed) with a dryer style vent. One 8" passive backdraft vent opposite lower corner for intake air. The intake air (filtered) comes from the basement.
This is my third grow in the room and I'm having trouble keeping the temp down for the first time. (Obviously, winters aren't a problem) I run a dehum. in the room which controls the humid fine, (currently rens between 40-50% RH) but it kicks off to much heat. I've tried a diff dehumid whith the same heat issue. I also run a dehum in the basement proper and can keep the overall basement humid at whatever I set it, i.e. 50%. But it too warms the basement up.
My daytime room temps are in the low 80s, though a laser temp gun reading from the top leaves/buds usually doesn't go over 80° and a shot of the soil surface is usually in the mid to upper 70s. Night time temps are in the mid 70° (dehum. runs more at night giving off heat so temps don't drop much).
Sorry for the long winded explain.... My questions:
1. Following the VPD (or is it VDP) chart, at a temp of 80 the humid should be a lot higher. However, I know that excess humid is not good, especially late in flower. So do I not worry about the higher temps and work at keeping the humid lower, or should I let the humid rise to match the temps? Or, leave it as it is?
2. Does anyone have a suggestion for cooling off the room? Even with the house A/C running 24 hrs, the room temp doesn't change much, though the humid drops a bit. I've thought about a portable A/C unit, but they need to be vented outside. My closest window is in the basement proper, 15 ft as the crow flies from th grow rm wall. I've also looked at a mini split solution, which is probably a better choice, albeit the cost.
Any ideas would be appreciated.
Assuming your Vortex exhausts 400CFM...
Your inlet needs to be sized to allow the fan to "free flow" (no static pressure) to achieve 400CFM. At 400CFM you would need a 192 Sq. In. hole to allow the fan to exhaust at rated speed. Or,
FOUR 8" holes with no inlet filter.
Now, add a filter and controller to the fan, and your exhaust CFM drops. Without seeing performance curves and knowing where you set the controller to, I'll make up a number so you can see where I'm going with this.
The made up number is 250CFM filtered exhaust. Assuming the inlet is sized properly (120 sq. in. or a little over
two 8" holes)
The point being, I don't believe you have enough passive inlet to take full advantage of your exhaust fan unless I missed something in your description. And, I think you said the 8" inlet hole is filtered, which makes matters worse.
It may not solve all your heat issues, but you paid for the fan, paying for the electricity... take full advantage of your hardware.
PM me and I can be a lot more help if needed.
EDIT: Forgot to mention, the 15' of duct, any bends in the duct will greatly reduce your CFM. So 250CFM just got lowered to 175... which means a smaller passive inlet also. But, once you get these hard numbers from the performance curves, you can check against standards developed from the HVAC industry to see if you have enough CFM to remove heat from your room.
Sorry, way to much detail/information/math for a forum. I'll put everyone to sleep.
