Need ideas for ducting ac holes

[indochronic]

Hi there, im building a 3 x 3x 5F box and i have ducting and pc fans i plan on leading to a hole in the wall going directly to outside. its a shed stud wall and im trying to think of a way to make either two small enough holes for intake and out or one almost the same size as the 120mm ducting and have a Y piece where the hot air goes out and the fresh cool air in? The reason for this is i dont want to make a load of big holes in the wall and end un having a draft or f iv to move the box. It also gets cold in the winter and sometime to wam in summer, so il need some sort of cut of or vent door. All comments are welcome

 

[Weaselcracker]

Could you post a picture of the situation/wall/hole if possible?.. I'm a bit unclear. You have one hole in wall that isn't quite big enough for two ducts (in and out)? Ideally it would be better to have two holes in your wall, corresponding somewhat to the holes in your grow box. The more length and bends in your ducts the less airflow you'll have. I made a passive system- fan outlet on thermostat at top- air just sucked in at bottom, with a hinged door on the bottom inlet that sucks open when in use and seals nicely when the fan goes off. That sort of thing would begin to help with your cold problem. Could post a picture late tonight if it's going to help but it's nothing too amazing, just slapped together but works well.

 

[indochronic]

Ill take a pic tomorrow when its bright and draw out what i mean in the pic, it be easyer to explane. But that door thing sounds good id be glad to take a look at it if u can upload the pics Im concidering on putting a panty hoe kinda thing on the end of the ducking to stop duct and the likes haha. i was thinking of a more permanent door for the outside aswell for winter cold because the walls arent that thick anyway.

 

[Weaselcracker]

Ill take a pic tomorrow when its bright and draw out what i mean in the pic, it be easyer to explane. But that door thing sounds good id be glad to take a look at it if u can upload the pics Im concidering on putting a panty hoe kinda thing on the end of the ducking to stop duct and the likes haha. i was thinking of a more permanent door for the outside aswell for winter cold because the walls arent that thick anyway.

Alright... This is what I made for my passive air intake. I made do with what was on hand at the time. It's the bottom of a square white 4 gallon plastic bucket. I painted it black and attached it to the intake vent with a hinge. The plastic is light and strong and easy to screw a hinge to.The ducting is 6" and the part that sticks into the room has a swiveling 90 degree section. I swiveled it till it was at a good angle - so that gravity kept the door sealed against the duct mouth, but it swings wide open easily when the outtake fan comes on and starts creating a vacuum in the room. I glued some soft (fleece) black material on the side of the door that meets the duct. It shuts silently and sit flush against the metal.

In the picture above I'm propping it open with a stick...

Opens when the outlet fan kicks on, closes when it goes off.

It's important how you put the hinge. It has to open (duh) and seal against light/air as much as possible when closed. I have a screen on the outside end of the duct against bugs,etc. The outside end is in a dark spot so this set up is lightproof as is now -though some setups would want to add a couple bends to pipe to shut out light.
Anyway- this is what I came up with. Fairly basic but I hope it helps. Has worked well for me so I haven't had the need to make anything prettier yet. I'll clean it up and paint it to look nicer someday.

 

[Ascended]

Hi there, im building a 3 x 3x 5F box and i have ducting and pc fans i plan on leading to a hole in the wall going directly to outside. its a shed stud wall and im trying to think of a way to make either two small enough holes for intake and out or one almost the same size as the 120mm ducting and have a Y piece where the hot air goes out and the fresh cool air in? The reason for this is i dont want to make a load of big holes in the wall and end un having a draft or f iv to move the box. It also gets cold in the winter and sometime to wam in summer, so il need some sort of cut of or vent door. All comments are welcome

You are going to want to use two holes minimum, one for intake one for outflow. If you try and use one hole all your doing is making it harder for your girls to get the actual cool air they want and need since the inlet would also be taking in some of the hot air as it was expelled. I would recommend putting the outlet higher up than the inlet (hot air rises of course), and maybe working out some sort of system like @Weaselcracker showed (genius in its simplicity by the way) to block out any extra light you might get.

 

[indochronic]

this is basically what i mean in pic

i think il go with the two holes and make them smaller then the ducting, probley the best idea. since heat excapes fast when it can, im gonna make the hot air out hole smaller and the air in one abit bigger and just come up wth a contraption like u did urslef

 

[Dutty Panty]

I would space the intake and exhaust different if possible intake from one side and exhaust from other side of room. That way you are creating air flow as well

 

[indochronic]

i plan on attaching one to the top of the box (hot out) and one at the bottom middle(cold in) with an extra bit of duct hose in the inside of the box incase i need to point it a certin way or towards a certin plant