AC Boxes Made Easy (to understand and build)

[BudGood]

H Daddy, just want to thank you for the informative thread. I used the aluminized foamboard to create exhaust and intake plenums for my co2'd room, worked like a charm! I'll post pics when I can...Thanks!

 

[CaptainStoner]

Hoosierdaddy, i got a buddy who works in the car a/c trade and i'm a bit of an electrics dude.. I can get hold of fairly small a/c system parts like they fit in cars but smaller - small cars in mostly cold countries don't need big a/c.. i was just thinking.. could it be possible to hook up a car type system with long pipes from the main unit, leading to an outside (always shaded, always cold area) radiator.. it could have cool airflow, its just there's an abundance of wind power here (24/7) and i reckon with the turbine i got i could hook up and power a motor to drive such an a/c to work in summer just to take the heat out of my box a bit.. it does get warm in here but a little a/c would sort it, esp with a few other bits i got.. think it could be done? my buddy can handle the drain/pressure check/regas

 

[hoosierdaddy]

Sure it should work. Give it a go.

You can also fit up an auto aftermarket heater to cool with. Run a trickle of tap through it during lights on, and catch the runoff in a drum for watering use. Or you could recirc through a heater core unit if you had a chiller for the water.

 

[CaptainStoner]

Yeah i've thought about tec coolers but they're too inefficient.. unless something could be used from a small waeco type compressor coolbox

 

[Plumb]

Hoosierdaddy, thanks for the excellent tutorial.

Do you think that an 8" vortex (740cfm) will be enough to vent a 15kbtu unit?
The ac would have only the exhaust end boxed in, go through 8" smooth bore ducting with no bends/restrictions. I believe that the ac unit has a 14" exhaust fan.

Thanks

 

[hoosierdaddy]

I think that set-up would work quite well, Plumb.

 

[SKUNK420]

Hoosierdaddy, i got a buddy who works in the car a/c trade and i'm a bit of an electrics dude.. I can get hold of fairly small a/c system parts like they fit in cars but smaller - small cars in mostly cold countries don't need big a/c.. i was just thinking.. could it be possible to hook up a car type system with long pipes from the main unit, leading to an outside (always shaded, always cold area) radiator.. it could have cool airflow, its just there's an abundance of wind power here (24/7) and i reckon with the turbine i got i could hook up and power a motor to drive such an a/c to work in summer just to take the heat out of my box a bit.. it does get warm in here but a little a/c would sort it, esp with a few other bits i got.. think it could be done? my buddy can handle the drain/pressure check/regas

Automotive a/c systems are just like central or window a/c. The only difference is the compressor is run off the crankshaft of the car's engine. If you plan on using the car a/c compressor your going to need an electric motor that can spin the compressor up to it's proper operating speed.

 

[njayjay]

Im trying to cool a bedroom with a window and a vented growtent inside using the AC box im wondering can i box out both the exhaust and intake and run them both out thru the window, or can you suggest a better setup for my needs? I also have wooden shutters on the outside of the window which I want to keep closed to conceal the suspicious vents, would they still allow enough airflow for the unit to function? Thx in advance

And btw theres a lot of bullshit flying around on the subject, this thread should get stickied or added to the links thread

 

[hoosierdaddy]

You could effectively run two ducts to the covered widow. You need to measure the openings and add them all up so you can see just how many cubic inches of area the vents in the shutters make up. If you were to pull in air with a 6" duct, and exhaust with a 6 inch duct, your shutters will need to have a very minimum of 56.5 sq inches of area.

You could place the intake down low on one side of the window, and the exhaust up high on the other side, to keep the airs separated. The hot air will rise and the lower intake should never see it.

 

[HeD333]

Hoosier: After reading this thread, thoroughly, I believe that I see more improperly engineered AC setups than I see properly engineered ones. Thanks for this guide, I just about made a big mistake...

 

[hoosierdaddy]

No problem, HeD333. You are exactly why I did the thread. Glad you got some help.

 

[BongRipkenJR.]

I like it

 

[ogatec]

just read the 1st page, best window banger tutorial out there..... thanks, you are a true jedi master!

 

[hoosierdaddy]

Many thanks!

 

[McChris421]

Hello all I had a question about an a/c box. I built one around a 25,000 btu box and it was working for about a week. Then last night the a/c quite blowing cold air and started blowing room temp. air. Every once in a while (every couple of hours) it will blow cold air but the a/c sounds like it is exerting more energy than it used to. My question is i have 1 6" 424cfm fan bringing air into the intakes and another exhausting into a different room. I know the design of the box is correct i am not worried about that i am however worried about the strength of the fans....too much, not enough? Thanks for the help and great thread btw.

-McChris421-

 

[hoosierdaddy]

The size of your ducting is the bottleneck in this instance. That unit needs lots of air, as it is pushing lots of energy. I would go 8" or 10" duct. You could still push air into the unit with the fan and the 6" duct, but add a Y to it and add an additional intake duct, either another 6" or better 8".
If you aren't too far from back of unit to exhaust port, the units fan should take care of the rest without any fan help on the back side.
It is cycling because there is not enough air supply to satisfy it and keep the coils cooled.

 

[lvmcgoo]

I love the forced air idea thank you .

 

[mrdizzle]

I have a thought

I was thinking of setting up a 18000btu a/c box. I understand your principle that the intake air shouldnt be mixed with the hot exhaust air. my outside air would be chilly like 45 pretty much all the time

looking at a a/c today i noticed that the vents for the ambient air arent all that passive. kinda small, so im thinking a 6inch passive intake would be about the same as the vents

if I set up a 8in max fan for my exhaust, could i take off the metal shell around the back of the a/c then just build a wooden box around the open part. a massive amount of air would be pulled over the whole back of the unit cooling it better than it could ever be cooled outside on a hot day

 

[hoosierdaddy]

Normally the vents for the intake air are located on two sides and the top of the unit. If you measure one of the slots (width x length) and then multiply that measure times the number of actual vent openings, I think you will find the the square inches is more than you thought it was. But in any event, if you enclose those vents, or make a new cover for the unit, you need to have an intake duct that will equal the square inch measurement the vents make up.

All of the air goes through the coils in the back of the unit. If you are not providing enough opening for intake, the unit will be starved and will not cool as well as it could have. In other words, no matter what the ambient temp is, if you are starving it for intake air, it will not work as efficiently as it would just hanging in a window.

A unit hanging in a window will cool better in 90degF temps, than one with a box and too small an intake orifice in 50degF temps.

 

[mrdizzle]

so i could take off the metal shell that covers the back for the ac, build a large wooden box around it and use like a 10in passive with a 8in maxfan venting the box? I'd use hardducting in and out. I feel like those maxfans are so crazy strong that would be pulling a ton of air over the back of the unit