Homemade Air Conditioner

Howdy all,

Please help with any insight/criticism that you can.

I have a multi-layer stealth cabinet (approx 3' x 4' x 7') that is tough to keep cool. It has a 250w HPS and 100+ watts of floros in the flower layer, as well as 100+ watts of floros in the veg layer.

The cabinet is in a room that is approx 12' x 12' x 10'. Right now, I use an open window to keep ambient temps in the room at 50 - 55 F. This allows temps in the cabinet to stay at about 80 - 85 degrees. That is a 30 degree difference between ambient/cabinet. I do have a plan in place that increases ventilation to the cabinet and should cut that number in half. Still, I have a dilemma.

During summer, outside temps here may remain as high as 90 F, even at 10pm when I turn on all the lights. Although the room is a little cooler, it can still be as hot as 85 or higher in there. Thus, even using mother nature to lower the temps, I will still need something that reduces temps in the room by 10-15 degrees, if not more.

Here is my solution. I have all the materials handy, so this would cost me $0. Basically, the idea is to put a cooler in a cooler. The smaller cooler has a pump pumping ice cold water through copper tubing that is wrapped throughout the larger cooler. The larger cooler is also filled with ice, such as those rectangular ice packs and frozen 2 liter bottles. There is a vortex fan outputting air and maybe a CPU fan or passive intake on the other side. The plugs and tubes are run through well sealed holes.

We all need to find a way to deal with hot summer temps, this could possibly be an easier solution than a cheap-o window A/C unit. But I would love to hear what everyone else has to say.

Thanks in advance, and good luck.

@90F the ice won't last. Do it right with a real AC or just grow enough in the winter to hold you over.

^^^^^^thats about all you can do

I ran into that problem last summer with a slightly more ghetto contraption meant only for cooling me off as I sat on the couch getting high. Too much ice for my tiny freezer to produce.

In any case, I appreciate the feedback. This will likely spur me to buy a cheap window A/C unit in the off season while they are cheap as hell.

Nonetheless, I do plan on trying this design first since, like I said, I have all the materials handy. If it doesn't work to chill the room, it can at least keep me a little cooler while I sit on the couch getting high.

12 volt a/c rip one out of a car at scrap yard the lot then build something to house it get a car charger and bobs your uncle (make sure its been regased before you start) most m.o.t test centers do it cheap

Yeah - car a/c is pulled by the belt, and not by your uncle bob's charger.

highaltitude said:

Yeah - car a/c is pulled by the belt, and not by your uncle bob's charger.

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hes talkin with a 12volt motor with a pulley pulling the compressor. Im a certified HVAC technician and it seems very hard to believe that this will work. Cant you just get a vortex fan that has 500 cfm

sagensour said:

hes talkin with a 12volt motor with a pulley pulling the compressor. Im a certified HVAC technician and it seems very hard to believe that this will work. Cant you just get a vortex fan that has 500 cfm

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Licensed myself. First prob is you can't pull the system out without opening it up; releasing the freon. (though scrap yards are supposed to recover the freon when it first comes in) This leads to the next prob, how to recharge the system? Happen to have a vacuum pump? (they start @$200) THen a gauge to know its down far enough. Then leak test.

The the 12 power supply. Its gotta be HUGE. Running that compressor is gonna take a bit of power (but no *need* for that motor to be 12VDC, can easily be a 120VAC motor, properly sized.)

Using an old refrigerator would be a whole lot easier

(Obviously this isn't directed at you, but Coolvibes and anyone else thinking about this)

thought about it some more and come summer i will have ago, but i think with a motor maybe from a hairdryer and a geared down ratio will solve the motor as a hair dryer plugs into the wall as about getting it regased when my landrover ran out i pulled into garage for 35 quid including vat they regased the ac in about 3 seconds so thats not a problem the problem would be turning it of so it dont hit 0 the bits are their you dont need an engineering degree to work it out simple if you look at it????

problem is mate most people pull there clean air from outside and in the summer would just not work i found that there is a heater blower from argos 24.00 GBP but wanted a freeish solution

I love you smart people.
Making me feel all shitty when i read and can't comprehend.

warm.

they have the car units already packaged into a housing now ,they call them air conditioners , they fit right into a window or are available in a free standing unit

If you're having heat issues and your cabs not working out, hit-up craigslist and find a small fridge.

My dad bought this little3 1/2 foot magic chef fridge that i have fell inlove with. it seems so perfect to hold three medium sized plants.

Unfortunately it's down at our shore house, so I'll have to buy one myself.

Check this out, sounds like the same thing you're planning - maybe it'll help you build it.
https://www.rollitup.org/do-yourself/215949-doobieus-cooler-home-made-ac-2.html
I would consider getting intake and exhaust figured out first. The ambient temps in my house are between 65-70C, and this is the air going into my flower room - keeps it at 78C lights on, with a pair of 400w HPS in there. No way should your box be that hot with proper airflow - especially being that cold outside it. And if you don't have proper airflow, you're going to run into a lot more problems down the road than just heat. (Mold comes to mind right off the top)

BigBudBalls, you are awesome. Thanks for the education with respect to using a car A/C. That is not something I plan to do for any price over $1, as my homemade A/C is already free.

DoeEyed, thank you for your concern which is spot on. My airflow is good, I keep constant watch on my Rh (usually 20- 30% in flower layer, and 40-55% in veg layer) to prevent mold. But you echoed my main concern, which is the huge difference between ambient and cabinet temps. I am actually installing a new exhaust (which is a blower type fan, instead of an axial type fan) to help with this. More updates on this when I get back from Jersey and install it.

One more question though, before the update...Do you think my design would be mroe viable with cooler air? Even though temps at 10pm in Oregon summer can be up to 90, they are usually 55-77 degrees. And I would fill two coolers, one inside the other, with a shitload of ice. And have freezing water pumping through copper tubing!

Ahhh...I'm rambling. Goodnight all...

Well, if you're not spending a lot of money on the idea, it's certainly worth a try. If it doesn't work out, not much lost, back to the drawing board and we'll help you brainstorm some new ideas.

go on craigslist, buy a used window unit AC for like 40 bucks. put the cabinet near the window and fab a duct into the back of the cabinet! seems very simple to me. dont do the auto AC way to much goes into it! Ive seen used window units go through the free section on craigslist (rarely) but you can get the in good working shape for cheap! if you do it id say add a filter in too but thats up to you. good luck

ORRRRRR......... get a used mini fridge on there, take it apart and use that as a mini AC unit inside your grow box. could just turn ur grow box into a fridge! all this can be done under 100 bucks for both systems very easily!

Thanks for the excellent ideas, boosted2j.

Auto A/C idea is too much in terms of cost. I've thought about the mini-fridge, but again, cost.

I am going to buy a window A/C unit for cheap if this idea does not work. I will test this idea early summer/late spring while temps ain't so bad, and upgrade to a window A/C unit by summer proper if need be. But I have no good way of stealthily ducting from the window to the cab, as the cab is custom built and secured to the studs in the wall by screws. So, I will have to find a way to decrease the difference between ambient/cabinet temps from about 30 degrees to 10-15 degrees.

Thanks again for your input!

dukeofbaja said:

One more question though, before the update...Do you think my design would be mroe viable with cooler air? Even though temps at 10pm in Oregon summer can be up to 90, they are usually 55-77 degrees. And I would fill two coolers, one inside the other, with a shitload of ice. And have freezing water pumping through copper tubing!

Ahhh...I'm rambling. Goodnight all...

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Run the lights at night (or during the coolest part of the day)