Air Conditioner Compressor Mister

[Kaje]

Punch line: Installed a water misting system on my residential Air Conditioner compressor and it really did cut down on my electric bill!

Background: My Air Conditioner compressor is located in the worse spot from an efficiency standpoint. It is on the West side of the house with no shade therefor when the cooling demand is the greatest (in the late afternoon/evening) the compressor is just simply baking in the sun.

Setup: Cool-n-Save Mister (http://www.coolnsave.com/) $70 on Amazon.

And while the mister is a stand alone unit and does not need further automation I still put some automation in . Inline to the mister I have a Orbit Water valve (automated sprinkler kind) with transformer connected to a Cooper Z-wave electrical outlet. So as not to waste water I inhibit water flow when it is raining and during the night. The system would probably be more efficient if I didn't inhibit the water at night and will probably be something I experiment with later. I also inhibit water when the Thermostats are not calling for cooling. Technically I don't need to inhibit when there is no Thermostat call for cooling but I wanted to have it as a redundant water leak prevention.

Results:
Average Monthly Electric Consumption 2010-2011 versus 2012 when the Mister was up and running:

2010/11 Ave vs. 2012
Jun: 4076 KWH vs. 3691 KWH (385 KWH Delta)
Jul: 4879 KWH vs. 4705 KWH (175 KWH Delta)
Aug: 4868 KWH vs. 3852 KWH (1,016 KWH Delta)

2010/11 Ave vs. 2012
Jun: 19.8 KWH/DD vs. 15.6 KWH/DD (4.2 KWH/DD Delta)
Jul: 15.5 KWH/DD vs. 11.6 KWH/DD (3.9 KWH/DD Delta)
Aug: 18.4 KWH/DD vs. 17.0 KWH/DD (1.4 KWH/DD Delta)

Where KWH/DD is Kilo Watt Hour per Degree Day. Where Degree Days are calculated based on a 68F Base Temperature and derived from the BizEE Degree Day website (http://www.degreedays.net/) for my area (Southern Indiana).

2012 (last year) was an especially hot year so I was extremely happy to see the drop in KWH used and the KWH/DD further shows the savings by normalizing the data to the weather situation.

I can't really comment on the water consumption because I did see a substantial increase in the water usage but last year I also did a lot of plant water automation which should account for most of the increase in water usage.

Ken J.
HSPRO 2.5.0.80, Applied Digital Ocelot 2.2.2433.35446, HSTouch Server 1.0.0.60, iAutomate RFID 1.1.0.0, NetCAM 1.1.0.1, TED 1.2.0.3, UltraMon 1.1.4743.28927, UltraWeatherBug 1.0.4738.21017
88 Z-Wave nodes, 3 Z-Trollers, Ocelot (4 SECU16, 1 Relay8, 6 Bobcat T, 1 Bobcat H), 9 iAutomate tags

[Olbrit]

Hi Ken, very interesting project. Are you getting any deposit build up that you can see on the coil and fan?

[rmasonjr]

Interesting. Both of my units are also in direct sunlight for the majority of the day. They face south and get the rising and setting sun. I'd be curious about deposit buildup like Olbrit. I did recently clean my coils with a spray cleanser as they were somewhat dirty.

[Kaje]

Hi Ken, very interesting project. Are you getting any deposit build up that you can see on the coil and fan?

I live in Southern Indiana and have 'limestone' water so I am also concerned about the potential for buildup. The Cool N Save comes with one water filter, I put a second filter, a Culligan RV water filter, in addition. After one season the cooling fins have a white-ish look to them on the edges. I took 'lime a way' to them and it didn't do a thing, so I don't believe it is a calcium/limestone buildup, just the old fins that are getting misted looking different. Nothing noticeable on the rest of the unit (coils, compressor, housing). I will post some pictures next week.

[Pete]

Curious if you have added temperature sensors on the in/out compression lines to the compressor and measuring electrical use of compressor?

[Kaje]

Curious if you have added temperature sensors on the in/out compression lines to the compressor and measuring electrical use of compressor?

I didn't put any additional sensors on the unit. I have TED on the main house line for overall power readings but isolating the A/C usage would be difficult.

You made me think on the temperature sensors. I guess you are implying if I measured the in/out lines I could get a more direct measurement of how effective the misting is. Aka if misting at night is worth it or not?

[langenet]

I didn't realize that this could make such a difference.... I'm on well water which is reasonably hard - not excessively, so the deposits would be something I would need to consider as well. '
Mine bakes in the sun as well.
Like the idea of automating the water usage... hmmm perhaps yet another project

Rob

[Pete]

You made me think on the temperature sensors. I guess you are implying if I measured the in/out lines I could get a more direct measurement of how effective the misting is. Aka if misting at night is worth it or not?

There is another HS user doing that today with his outside compressor, plus air in and air out temps et all.

Here I have a 1-wire network outside and it wouldn't be much more to add some temperature sensors to it.

Wondering if I could utilize some sort of rain bucket for the water source.