My goal in this hobby is to grow plants using cheap materials with minimal electrical power. I'm an eco-nut and just hate spending money on electric bills. So, here is my homemade swamp cooler. I made it for $25-30 and it draws about 50W. Hopefully, this will allow me to grow HL Nepenthes and Heliamphora, but my goal is to help everyone else out as well! Please comment with questions, ideas, and experiences.
I have confirmed that this cooler humidifies as well as chills air at least 10 degrees. My basement's air is typically 70F or 68F and 30% RH, and this cooler got the air down to 60F and the relative humidity up to 65%.
However, its effects in your conditions may be different. It will cool to a temperature very close to the dew point, so you can use this calculator to determine the temperature you could achieve. http://www.dpcalc.org/
-Sterilite tub (sizable, should hold 20 gallons I think)
-Fans (I used two Cooltron fans that can be found here: http://www.amazon.com/115V-AC-Coolin...tron+fans+115v)
-Evaporative cooling pad (also called humidifier filter pads, they should be water absorbant and porous)
-Nails (you can use screws and bolts)
-Drill and assorted bits
-Powerful cutting implement (I used tin snips and scissors)
-PVC tube (rigid and flexible)
-Meter stick or ruler
Assemble all necessary materials
Cut the evaporative cooling pad to a suitable size for your tub and trace it on one side. It should leave a few inches open beside it, and leave about 3-4 inches below it for the reservoir of water.
Select a large bit for the drill, and make a hole in one corner of the trace. Using the tin-snips, cut out the hole for the evaporative cooling pad. BE SURE TO MAKE IT A LITTLE SMALLER THAN THE PAD ITSELF. I learned the hard way that no overlap will lead to leaking later. Also, I like to cut in chunks, to make sure I didn't stress the plastic so much that it would shatter.
Drill six holes around the hole, one in each corner, one above the middle, and one below the middle. Cut six lengths of wire, about 4 inches long. Thread these through the pad and the holes and twist to secure the pad in place. There should be overlap between the pad and the tub.
Flip the tub over and place the two fans on the tub. Position them however you like, just make sure they are well above the water line, and well spaced apart. Trace the fan blades to create the circle you need to cut out.
Drill a few holes in the center, and use the tin snips to cut the two circles out.
Place the fans over the holes, and trim to perfection. Then, select a nail (or screw and bolt) that fits snugly through the holes in the fan's corners. Stick this through the holes, then press down and twist to make a mark where a hole should be drilled. Do this for each corner, then remove the fan and clearly mark with the marker. Then drill these holes with a drillbit that is slightly larger than the nails.
Then, insert the nails into the holes. Thread the fans onto the nails. Screw on the bolt if you have them. Mine were perfectly snug, and I left them as is.
Now you're 80% done, but this last part is hard and will take some more time. Here's where you rig the pump and PVC tube.
Begin by cutting the PVC tube to the length you want. I used clear, 1/2" diameter tubing. I cut it to be about 3' long. If it is a little too small to fit over the pump outlet, try heating it with a lighter or something to stretch it. That's what I ended up having to do.
After you have the PVC attached to the pump, prepare the mounting equipment. You're going to need five pieces of wire, about 2.5" long. Hold one end down on a flat surface, and use the wire pliers to curl them into hooks. The hook should be just a little smaller than the tube. Then you want to drill five holes into the tub, directly above the cooling pad. Placement doesn't matter, just keep them even.
Now you want to thread the wire hooks onto the PVC tubing. Lay the tube flat against the tub and the holes you drilled. Mark with your finger where the hook should go, pinch down on the tube, and slide it on. It should stick on firmly. Once you have all of them attached, thread them through the holes, and use the wire pliers to make hooks on the other side, so that the wire stays in place.
Now that you have your tube in place, you can start drilling your holes. There is no easy way to do this, but what I did is lay the tub on it's side, pad facing down. I then reached the drill inside, and turned it so it faced the bottom of the PVC tube. I drilled about 8 little holes. MAKE SURE THEY ARE WELL-DRILLED HOLES WITH NO PVC DEBRIS IN THEM. THIS WILL BE A PAIN TO FIX LATER. Once everything is drilled, turn it right-side up and plug the end of the tube with something. I found that an aluminum foil ball stuffed in the end created enough resistance to make the water come out the holes, but also left enough of a gap so that nothing was spurting or exploding
Here's what it should look like:
Now you can place the tub's top back on (it should bend over the wires) and plug everything into a timer. Any odd holes you can re-drill. I had to fix the duct tape mess I made at the end of the tube and direct the spurting water down onto the pad. But otherwise, you're done the cooler! Fill it up with water every couple of weeks, and enjoy your highland plants!
I will post later this winter when I have the grow shelf and duct the cold air into the HL chamber. But thanks for looking, and comments are welcome!