If you have a cooler, whether it's a compressor/condenser style or an evaporative, or swamp cooler, there is always going to be some waste water involved. During the 100+ season, this is especially true, and it can create problems like unwanted weed growth around your machine and possibly damage to your foundation. In addition, the tap water here is piped in from remote locations and it's finite. Waste is dumb when you can prevent it easily, so I looked around for materials to create a solution.
Step 1: Gathering the Parts
I didn't take photos of the assembly process, because to be honest I was winging it and wasn't sure it would work. Here instead is a shot with the parts explained.
1. An aquarium or reptile tank. Mine's about 10 gallons. I picked one with a screen top to prevent mosquito breeding. You could probably adapt the design to a hooded tank, though.
2. A low volume fountain pump. This one still has the fountain attached, but you could hook tubing to a bare one and install it in any kind of fixure you could think of. If you are just using an aquarium, you might be able to use the existing filter system and hack it to add an output.
3. Heavy duty duct tape.
4. Access to a file or rotary tool.
5. An outdoor source of electricity.
Step 2: Putting It Together
1. Find your condensate output. On an a/c unit, there will be a pipe coming from the house, usually near the compressor unit. On a swamp cooler, there will usually be a length of tubing. Position your tank so that it can receive the drip most effectively. The condensate will leak into the tank, slowly but quite surely. After a day or so, the tank will be nearly full. It's time to put that water to use.
2. Remove your screen, submerge the pump and make sure the output tube fits securely. Many of these have suction cups which will be helpful. Note that running a pump dry will damage it.
3. Modify the screen.
If you have a sliding screen use a file or rotary tool to carve out a pair of divots for the pump's power cord and the output tubing. I found that it produced a better fit, but didn't carve enough to prevent the tank from being useful in its original purpose. If you have a screen that clamps on, you could use pliers to give the power cord and tube somewhere to sit.
4. Position the pump so that it will flow back into your tank. In my case I found an easy hanging spot on the gas meter, and will probably secure it with wire.
5. Seal any gap between the screen and tank with duct tape. I prefer Gorilla tape because it has a longer life span outside.
You're done. Plug in your pump and you have a recycling fountain. Interrupt the flow with a bottle, and you have an easy way to water your plants.
Step 3: Good on You, You Just Saved Some Water From Oblivion (but Be Careful With It)
Please note: I do not intend to use this water for drinking, and I don't recommend you do it either.
For the curious, I just called a local HVAC shop and asked about the toxicity of condensate. I was told that it should be fine, because it's just water vapor collected from the air, a by-product of the cooling process and not involved at all with the freon. They said it was fine to use for watering plants.
Since then, I've been notified via comments that it's not the water I should worry about, but the path it takes to the collector. In my case, it's an old pvc pipe which has seen better days. In the collector, the water is exposed to air and sun, so it's essentially a bacteria farm. I've been warned about Legionnaire's Disease, and I'm sure it's not the only bug that could be growing in this water. Until I know for sure, I will be using this water only for decorative plants and not for veggies.
In the meantime, I've decided to simply divert the condensate, via pvc parts, into a homemade planter built from a used tire. I've transplanted aloe plants into fresh soil and I'll be monitoring them to see how they respond to the condensate. At least this way something's getting watered, the water doesn't go straight to my foundation, etc. One experiment begets another.
Thanks to everyone who's been giving me feedback and suggestions.