You can get improved cooling, and lower power costs with this method.
An air conditioner works by compressing a gaseous refrigerant until it condenses in the (you guessed it) condenser on the outdoor side. This releases heat outside. Then when that refrigerant is allowed to evaporate in the....Evaporator (clever the way they named these, huh?) which absorbs heat from the interior of the house.
When water is sprayed on the hot condenser, and that water evaporates, it makes it easier for the compressor to turn refrigerant from it's gas state to a liquid state. This means cooler air in the house, and less power consumed!
I'll show how to be safe with this project, then the first 3 options I've built, and finally data which back up my assertions of cooler interior air and lower power consumption.
Step 1: Be Safe !
Don't get electrocuted.
A GFCI (ground fault circuit interupter) will prevent electrocution in many circumstances.
Even with this, don't be stupid.
Although this was my last step, it should be your 1st step. ;)
This project does not require opening the air conditioner. Nonetheless, i'll give some pointers on staying alive with electricity.
The GFCI, (or GFI) protection will prevent electrocution in the event that you become the conductor between a live wire and the damp ground. The first step really should be "_don't become_ the conductor__ between a live wire _and ground_." You may ask "how do I prevent that??"
Keep an eye on your footing. Are you standing in a puddle? Are your shoes wet? Then don't touch electrical parts.
Are you opening something electrical? Unplug it. if you've opened a device that includes a capacitor, unplugging the cord is not enough. the capacitor holds a charge, and must be discharged.
The "one hand in your pocket" rule is often a life saver. If both of your hands are on an electrical circuit, power can run through one hand, through your chest (where your heart resides) and down the other arm. That would not be good. Only touching a device with 1 hand prevents power going through your heart.
Step 2: Portable GFCI
Here's a bit of info from the portable GFCI I plugged my unit in to. It is also possible to permanently install a GFCI outlet, or even a GFCI breaker.
Some people would say "just don't work with electricity and water." I say be smart about it. If you understand electricity, all sorts of things become possible. Ice makers in the freezer, electric water heaters, boiling water on an electric stove, and this project.
Step 3: Garden Sprayer
Let's get started with Build Option 1.
This is nothing but a garden sprayer which one pumps up with air over water. It is set to mist water on the condenser (the hot side of an air conditioner which vents outdoors) As the water evaporates, it helps the air conditioner. I've never had anything harsher than soapy water in this garden sprayer. I would not advise using a sprayer which has had pesticides, etc. in it.
Pump it up, lock the button "on" and it's good to go.
I haven't yet put it on the stopwatch to see how long it lasts. Since this side of the air conditioner is on the outside of a window, and it does sometimes rain, we haven't really done anything that goes beyond the normal use of the machine. .. Yet.
ADVANTAGE: Option 1 applies water thinly over a broad swath of the condenser. It is also ready to go off-the-shelf.
DISADVANTAGE: This is only a 1 gallon sprayer. so it doesn't last long. A larger sprayer would be better.
Step 4: Option 2: Self Starting Siphon
This device makes use of what I call a self-starting -siphon to produce a slow trickle. "Self Starting Siphon" is to be another of my instructables. In this case, a paper towel is drawing water from the plastic jug into the yellow and green funnel tube by capillary action. The yellow tube was a syringe type squirt gun from the dollar store repurposed to this task.
Step 5: Hole in the Air Conditioner.
The squirt gun nozzle was a snug fit for surgical tubing after wallowing it out a bit with a knife.
I carefully drilled thru the body of the AC, taking care not to drill into the condenser. Water from the paper towel drips into the surgical tubing. The tubing is inserted in the hole in the body of the air conditioner, and water drips right onto the condenser.
ADVANTAGE: to this system is a slow, continuous drip.
DISADVANTAGE: Unfortunately, with the heat coming off the unit, the paper towel tends to dry out. Perhaps some saran wrap would allow it to work better. It also seems that compressing the paper towel in the tube makes it less effective. So a larger tube would help. Perhaps a caulk tube. Also, a mist sprayer will probably cool the entire condenser better than a drip down the center of the unit.
Step 6: Option 3: Siphon Five Gallon Jug
This is a conventional siphon using medical tubing. To keep the inlet side of this tube at the bottom of the jug, I secured it to a steel tube with rubber bands.
Note to self: use something else before that tube rusts too badly.
Step 7: Regulate Flow
The flow from the tube onto the condenser was too fast, so I clamped it with a vice-grip. This allows flow to be adjusted to a drip every few seconds. It also weights the end of the tube in place.
ADVANTAGE: Since option 3 has the greatest water volume, it lasts the longest.
DISADVANTAGE: The vice grip isn't the best for adjusting flow. It often has a nice flow when first set up, but then, hours later has no flow although there is still plenty of water. Perhaps as the vice grip heats up, it clamps more tightly. A surgical clamp for adjusting flow is made of plastic, if I recall correctly. If I can get one of those, I will use it instead. Also, to re-iterate, a mist over the entire surface is probably better than the drip down the center.
Step 8: Scientific Test: the Control. Baseline Temp, 52F
Here are results of an experiment using an IR thermometer before and after squirting water on the condenser.
Before squirting down the condenser, air coming into the house was 52 F.
Step 9: Changing a Variable: Wetting Down the Condenser.
Then water was liberally applied from a squeeze bottle.
Step 10: Rechecking Inside Temp
Just a minute or 2 have passed, while wetting the condenser outside.
Re-checking the air temp coming into the house indicates about 47F.
That's a drop of 5 degrees Fahrenheit! Not bad.
Step 11: Baseline Temp at the Condenser.
This is the part which vents heat outside.
Before wetting it down, it was 95F.
Step 12: Condenser After Wetting
That's a reduction of about 7 degrees Fahrenheit.
Step 13: Power Consumed Before Wetting
I mentioned earlier that there are power savings with these methods. Here is some proof.
489 watts drawn with a dry condenser.
Step 14: Power Consumed After Wetting
After squirting down the condenser, it draws 411 watts.
So, it saves 78 watts!
That's 16% power savings!
Not only does water on the condenser make for cooler air in the house, but it saves power, and therefore, money during use!!