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will shading outside HVAc compressors help at all?

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  • will shading outside HVAc compressors help at all?

    I'm pretty sure most of the cooling power of AC compressors comes from phase changes, but just curious will shading the outside compressors help at all?

    what if they were installed underground? would that increase effciency since they would be cooling with cooler air temps?

  • #2

    Re: will shading outside HVAc compressors help at all?

    Re: will shading outside HVAc compressors help at all?

    Yes.
    You`d be amazed how much more heat you get in something sitting in direct sunlight. And if that something is trying to radiate heat it`s much worse.
    Putting one underground might be problematic for most cases, but that is essentially what a ground-source heat pump does.
    1220 Watts of PV, OB MX60, 232 Amp hrs, OB 3524, Honda eu2000.

    Ohm's Law: Amps = Volts / Ohms
    Power Formula: Watts = Volts * Amps

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    • #3

      Re: will shading outside HVAc compressors help at all?

      Re: will shading outside HVAc compressors help at all?

      Remember, full noon-time sun is around 1,000 watts per square meter worth of heat/energy. Anything you can do to help avoid having the A/C system move any "excess" heat will help.

      -Bill
      20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.

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      • #4

        Re: will shading outside HVAc compressors help at all?

        Re: will shading outside HVAc compressors help at all?

        I read somewhere not that long ago that shading the A/C condensor will save 10%.
        12 kw Generac, Honda EU3000is, 4.2 kw APC UPS powered either by battery or a Prius. Really.

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        • #5

          Re: will shading outside HVAc compressors help at all?

          Re: will shading outside HVAc compressors help at all?

          i agree shading it will help, but i would not place it underground as that is confining the heat the compressor is trying to get rid of.
          NIEL

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          • #6

            Re: will shading outside HVAc compressors help at all?

            Re: will shading outside HVAc compressors help at all?

            This is an interesting thread. My two main AC units see full sun from about 11:30 am to about 4 or 5 PM. I always thought an awning over them might help. I wish the house had been designed with them on the east side but I do understand they were not really looking for our kind of efficiencies in 1997. They did place them next to a walk in closet for interior noise suppression.

            I think I have some materials around to try a temporary sun shade over my compressors. When I get back from vacation I will try something out.
            Sticking it to the power company one watt at a time!
            60 Ningbo Electric 175 watt panels and 12 Canadian Solar 180 watt panels with 2 PVP 5200 Inverters

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            • #7

              Re: will shading outside HVAc compressors help at all?

              Re: will shading outside HVAc compressors help at all?

              http://www.fsec.ucf.edu/en/publicati...2-96/index.htm

              apparently the increase is only around 3 % or less

              and if you do it incorrectly you can actually cause the air flow to be compromised/short circuited so you decrease efficiency

              some guys at this hvac forum thought it was a waste of time.
              http://hvac-talk.com/vbb/showthread.php?t=174372

              I'll probably try it anyways. I've got tons of trellis I can use to shade it and hopefully not mess up the air flow.

              Wonder how high above the unit I should put it? the document shows a red air flow at the end that goes up maybe 6 feet high.
              the experiemental trellis was only about a foot above the compressor, but that is fine because that particular compressor had a side discharge.

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              • #8

                Re: will shading outside HVAc compressors help at all?

                Re: will shading outside HVAc compressors help at all?

                anyone try cool n save?
                basically it mists the incoming air.
                useless for high humidity, but if your air is dry makes sense.
                http://www.coolnsave.com/

                http://www.amazon.com/CoolnSave-CNS1...rBy=addOneStar

                not the best reviews. especailly if you have hard water.
                Last edited by rollandelliott; July 15th, 2012, 21:36.

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                • #9

                  Re: will shading outside HVAc compressors help at all?

                  Re: will shading outside HVAc compressors help at all?

                  Originally posted by rollandelliott View Post
                  apparently the increase is only around 3 % or less
                  ...
                  I'll probably try it anyways. I've got tons of trellis...
                  Interesting that you found it was only 3%, but heck, 3% on such a large load over the life of a house is a big savings!

                  Mine are in full sun starting mid-day. A few years ago I thought about using trellis, too, but not horizontally. I was going to mount it vertically a foot or two away, high enough and placed just right so it provides shade when the sun comes around the side of the house. No need for something overhead unless you are in the tropics with a high sun angle. Then I was going to plant an ivy or other permanent climbing plant to fill in the trellis' holes for full coverage and beautification. Never got around to it but I still should do it. As I transition to mini-splits I'm going to put those condensors on the opposite side of the house where they will be in full shade all day.

                  Edit: meant to say vertically...
                  Last edited by techntrek; July 17th, 2012, 9:35.
                  12 kw Generac, Honda EU3000is, 4.2 kw APC UPS powered either by battery or a Prius. Really.

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                  • #10

                    Re: will shading outside HVAc compressors help at all?

                    Re: will shading outside HVAc compressors help at all?

                    If you've ever read the instructions on a window Air unit, it suggests mounting in a windows out of the sun, if you switch a unit from one that gets full sun to a shaded window you will see a difference!

                    ...Of course having put 3" of foam core in the sunny window made a huge difference as well....
                    Home system- 20 - 200W Evergreen blems, 2 Classic Lites, E-Panel, 2 Prosine 1800 watt inverters, 800AH 24V forklift Batt, up and running 1 Classic Lite and 14 Suntech 185W in spare room.
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                    • #11

                      Re: will shading outside HVAc compressors help at all?

                      Re: will shading outside HVAc compressors help at all?

                      It may be a small gain, but in some cases - especially with marginal or weak systems - it can make a noticeable difference inside.

                      Definitely be sure to keep any coverings well away from the airflow of the unit. Even surfaces with holes - trellises, fences other than chain link, so forth - can restrict the flow enough to compromise cooling if placed too close. I've seen some fencing (around larger commercial equipment, so of course it's trying to move a LOT more air) that seemed to have lots of holes in it but provided enough of a restriction that the units would fail to perform on the hottest days.

                      As for misters, they DEFINITELY improve performance, but I would only use them as a last resort or on a really old unit I was only trying to limp along as long as possible. Probably depends on the mineral content of the water in your area, but I've seen condenser coils with the fins rotted right off of them because the building owner was misting/spraying their coils. One was funny looking - he had a lawn sprinkler sitting on the asphalt roof of his multi-story building so it would oscillate over the surface of the (very large - 60-75 tons) condenser coil! Another went to a LOT of trouble - installed plumbing in each unit, with little spray nozzles spaced along the tubing, then ran hoses all over the place. They had about 20 units across a factory roof.
                      Website: http://n5usr.net
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                      • #12

                        Re: will shading outside HVAc compressors help at all?

                        Re: will shading outside HVAc compressors help at all?

                        how were these misters turned on and off? Seems like the cheap one I liked too is not made that well. Lots of complaints of the flap valve breaking. Wonder if a solenoid valve wired to the fan circuit would be more reliable???

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                        • #13

                          Re: will shading outside HVAc compressors help at all?

                          Re: will shading outside HVAc compressors help at all?

                          Originally posted by RandomJoe View Post
                          As for misters, they DEFINITELY improve performance, but I would only use them as a last resort or on a really old unit I was only trying to limp along as long as possible. Probably depends on the mineral content of the water in your area, but I've seen condenser coils with the fins rotted right off of them because the building owner was misting/spraying their coils.
                          These days it is hard to find a window or other small A/C unit that does not splash the water from its evaporator onto the condenser, and it does make a difference. But that is effectively distilled water.
                          Sunny Boy 3000US, 18 x BP Solar 175b panels, installed 2009.

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                          • #14

                            Re: will shading outside HVAc compressors help at all?

                            Re: will shading outside HVAc compressors help at all?

                            I considered evaping the coil until I looked at the high pressure misting system we have. About annually we have to replace the misting jets because the calcium in the water. It leaves white deposits on anything the the mist touches. Not for my AC units I am afraid.
                            Sticking it to the power company one watt at a time!
                            60 Ningbo Electric 175 watt panels and 12 Canadian Solar 180 watt panels with 2 PVP 5200 Inverters

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                            • #15

                              Re: will shading outside HVAc compressors help at all?

                              Re: will shading outside HVAc compressors help at all?

                              you can get a cheap shallow well pump and a rain water collection system to supply water to the misters thus eliminating any hard water issues, though I'm guessing $200 for a pump system the return on investment might take a while????
                              I guess the biggest problem is having enough rain water! Cool n Save says they use 1.4gal/hr or about 100 gallons a week if AC is run 10 hr a day. Mistecology says 500 gallons a week!

                              Edited to add I just blew $5 on a ebook that supposedly uses something similar to what I proposed above
                              Solar Rain Barrel Water Mister For Your Central Air Conditioner.
                              I'll let everyone know if it works well.

                              in the mean time here is a home made mister system that uses an irrigation valve to trigger the misters.
                              http://www.keepmaster.com/homeprojects/homeNew4.html
                              i
                              https://www.lawngeniestore.com/Comer...s/54048_49.pdf
                              shows valve in detail

                              this is the most expensive mister system I found $500. Comes with a giant filter that goes around the AC compressor to prevent hard water deposits (not sure that is going to work?)
                              http://www.youtube.com/watch?v=3TETt...eature=related
                              http://www.mistecology.com/wp-conten...tion-Guide.pdf

                              this company had a youtube video but nothing on their web site
                              http://www.hydrobreeze.com/
                              might want to call them.
                              Peace!
                              Last edited by rollandelliott; July 17th, 2012, 5:36.

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