Thank you for posting such a great idea.
I posted this as a response in another thread but I decided to make this it's own thread:
So I've been brainstorming this idea for a couple months and I wanted to see what everyone thought out there.
My concept includes the following parts:
Copper pipe and copper "U" connectors
20 - 30 gallon insulated cooler (the kind you use to bring your beer to games or parties)
2 inline water pumps
icebox reflector cooler http://www.gchydro.com/Ice+Box.html
Decent fan for the icebox
1-quart ziplock freezer bags
PVC pipe (and adapters if needed)
First, build a stacked grid using the copper pipe and "U" connectors (you'll have to sweat the pipes) to occupy the space in the mini-fridge. Basically sweat the pipes using the "U" connectors to build a grid going back and forth. Once you've made the grid the width of the inside of the fridge, use a "U" connector going up and down to start another level of pipe. In the end the entire inside of the fridge should be copper piping.
Take some of the ziplock bags and fill them with water. Set these on top of a lot of the piping throughout the grid, but not enough to block the air-flow inside the fridge (leave some space in between the bags), otherwise you'll only chill the areas where the air can get to.
Drill two holes in the fridge and four in the cooler for the bulkheads. One of the holes in the fridge should be at the highest point and the other at the lowest.
With the PVC pipes and connectors, connect the cooler to an inline water pump and then to the highest bulkhead on the mini-fridge. The bulkheads on the fridge should be connected to the copper pipe inside.
Connect the lowest bulkhead on the mini-fridge to the return bulkhead on the cooler (gravity return).
Connect PVC to the other water pump on the cooler and then the water pump to the vinyl tubing. This will go to the icebox. Connect the return on the icebox to the last bulkhead on the cooler.
The icebox and fan should be mounted on the hood and should be exhausting the hot air past the icebox. This should provide cooling for the growroom. You don't want to chill the air going into the hood as hot air would still be exhausting out of the hood past the light. We want to cool the room more than the light. I don't know if blowing cooled air (probably with condensation) across an HID light at well over 1000 degrees would be such a good idea. I could be wrong though.
Multiple iceboxes, a larger cooler, and a larger fridge could be used for larger growrooms.
So it works like this...
The cooler is filled with purified water.
The water pump between the cooler and the fridge pushes water to the highest point on the fridge. The water goes through all the copper pipe. The ziplock bags help the fridge stay cold as water absorbs 4 times the heat almost 20 times faster than air and because they would be sitting on the copper piping, he pipe would be able to dissipate the heat from the water more quickly. So the bags full of water sitting on the pipes should work much better than if it was just air inside the fridge trying to absorb the heat coming from the pipes. The water is returned to the cooler via gravity since the water is pumped to the highest point and drained at the lowest.
The second pump sends chilled water to the icebox. The fan blowing air across the icebox will cool the growroom just like an air conditioner.
Some things to consider:
Instead of using more expensive inline pumps, the water may stay cool enough to absorb the heat being produced by the pumps if submerged pumps are placed in the cooler. But, it would probably mean your fridge would run more often to compensate.
The fridge, cooler, and icebox should probably be close to the same level to keep the water circulating enough to cool it down.
Actual "Chillers" can be used instead of a mini-fridge, but they seem to start at the $400 range so it's probably cheaper to convert a mini-fridge. Plus, if your chiller goes out that's an expensive piece of equipment to replace. If the mini-fridge goes out you can replace it for less than $100 if you look around.
The larger the cooler the more efficient it should be as changing the temperature in a large body of water takes significantly longer than a small amount of water. It would take longer to chill initially but once it's chilled it take a lot to warm it up any.
The fridge should be in another room. My design would have the fridge in the garage and pass the pipe through the wall into the growroom where the cooler sits. The mini-fridge is a heat exchanger. If you have your heat exchanger in the same room you're trying to cool, you are defeating the purpose. The fridge should be able to dissipate the heat it's exchanging. If the room where the fridge resides in is hot then the fridge will not be able to get rid of the heat. I would have fans blowing across the coils on the fridge when it's hot to help cool it.
You might be able to get away with a single water pump going from the cooler to the icebox and then to the fridge, but I imagine the pump would have to be fairly powerful because the water needs to move quickly.
Here are a couple reasons I would use two pumps instead of one:
The pump going from the cooler to the fridge can be set to run incrementally (like once an hour) to cool chill the water. You would want the water circulating the entire time the light is on though. The system may be efficient enough to where the pump doesn't have to run 100% of the time.
Before the lights turn on for the day, the water could be pre-chilled without having to run it through the icebox.
What does everyone think of this concept?
Thank you for posting such a great idea.
"I'll take my proven facts over your word any day"
Of course, if I have to be the brave one to be the first to attempt this then I'll probably just do it and post my results
I made a AC window mount into a self contained unit that sits on my floor ???????
hey unfortunately, im 98% sure your idea wont work. refridgerators really dont have that much cooling capacity... especially not a mini fridge. think about how long it takes to cool down a glass of room temperature water... about an hour? lets just say an hour. with the amount of copper pipe youre planning to put through there the total volume of water in the fridge at any given time will be more than a glass of water. you can calculate the total volume of water that will be in there if you want with the inner diameter of the tube and the length youre planning to use. now onto the exchange rate of water going through the unit. youll be using a pump with a certain gpm (gallons per minute) rating. if the total volume in the pipes is say a half gallon, and your pump is 1gpm, it will only take 30 seconds to move all the water though your fridge. if you use enough pipe for a gallon, itll last for 1 minute. this isnt enough time to cool that much water down, especially since most pumps are stronger than 1gpm. yes the specific heat of water is higher than air, but thats actually a problem, youll have a bunch of warm water that will be a bitch to cool off! it accepts heat very easily, but doesnt dissipate it quickly.
another problem is mini fridges work basically exactly the same as an air conditioner, so if youre going to go through all that trouble to cool your room, you might as well just buy a window a/c unit and duct it straight to your room. mine was 30 bucks off craigslist and has been running 24/7 for 2 years already. great investment.
if youre stoked on the idea of using an ice box, you might be able to make your own water chiller out of peltier plates. theyre pretty cheap off ebay, and with a quick google search youd be able to find a diy tutorial on how to do so. even with this option, id still recommend just getting a cheap used a/c unit.
its good to see people thinking and innovating though keep it up man!
so far i only found 1 AC thats actually worth making with a 100% succes rate.
its more work but it doesnt require building a AC with more AC's.
just a big long pipe deep into the ground, and out of the ground again, it will suck the air out the sky, into the ground, cooling it down a lot (like burrying your cola bottle on the beach to keep it cool) 1 fan on the inside that blows the air in your box and voila!
I hope this helped a little for anyone thats still looking for a homemade AC, if not, just stick with ice