will shading outside HVAc compressors help at all?

rollandelliott
rollandelliott Solar Expert Posts: 834 ✭✭
in Energy Use & Conservation #1
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?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    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.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    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
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #4
    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%.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #5
    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.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #6
    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.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #7
    Re: will shading outside HVAc compressors help at all?

    http://www.fsec.ucf.edu/en/publications/html/FSEC-PF-302-96/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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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #8
    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-CNS100-Cool-n-Save-System/product-reviews/B002QK9YZ4/ref=cm_cr_dp_qt_hist_one?ie=UTF8&showViewpoints=0&filterBy=addOneStar

    not the best reviews. especailly if you have hard water.
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #9
    Re: will shading outside HVAc compressors help at all?
    rollandelliott wrote: »
    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...
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #10
    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 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • RandomJoe
    RandomJoe Solar Expert Posts: 472 ✭✭✭
    #11
    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! :roll: 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.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #12
    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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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #13
    Re: will shading outside HVAc compressors help at all?
    RandomJoe wrote: »
    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. :-)
    SMA SB 3000, old BP panels.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #14
    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.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #15
    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/Comergent/en/US/StaticContent/LawnGenie/product_manuals/Valve%20Manuals/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=3TETt3MgYZQ&feature=related
    http://www.mistecology.com/wp-content/uploads/AC-Spritzer-Installation-Guide.pdf

    this company had a youtube video but nothing on their web site
    http://www.hydrobreeze.com/
    might want to call them.
    Peace!
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #16
    Re: will shading outside HVAc compressors help at all?

    Attachment not found.
    I wonder if these filter blankets are a good idea for any AC unit? I just cleaned my ac unit after 10 years and it was so filthy I had to use a bristle brush to remove the crud out of it.
    If there was a filter on the outside it would be obvious it needed changing.
    http://www.mistecology.com/order-now
    they cost $25.
    I suppose you could use those blue cheap air filters and somehow put them on the outside of your AC unit.
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #17
    Re: will shading outside HVAc compressors help at all?
    inetdog wrote: »
    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. :-)

    True, but the cheaper Fridgidaire I first purchased this spring made a horrible noise once the basin filled up and it started splashing. The LG I have now doesn't.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #18
    Re: will shading outside HVAc compressors help at all?

    On my last post on the prior page - about installing a trellis - I meant to say I would mount one vertically. Not horizontally. :blush:
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #19
    Re: will shading outside HVAc compressors help at all?
    rollandelliott wrote: »
    Attachment not found.
    I wonder if these filter blankets are a good idea for any AC unit? I just cleaned my ac unit after 10 years and it was so filthy I had to use a bristle brush to remove the crud out of it.
    If there was a filter on the outside it would be obvious it needed changing.
    http://www.mistecology.com/order-now
    they cost $25.
    I suppose you could use those blue cheap air filters and somehow put them on the outside of your AC unit.

    i don't see how choking it off of free flowing air will help it. this may allow heat to build up rather than dissipating it. this solution can be worse than having it in full sun imho.

    if i miss my guess here, these blankets are meant for overwintering and storage purposes and not for an actively working a/c unit.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #20
    Re: will shading outside HVAc compressors help at all?
    niel wrote: »
    i don't see how choking it off of free flowing air will help it. this may allow heat to build up rather than dissipating it. this solution can be worse than having it in full sun imho.

    if i miss my guess here, these blankets are meant for overwintering and storage purposes and not for an actively working a/c unit.

    Looking at the web page, it seems clear that these "filters" are being used as wetted cooling pads, essentially for putting an evaporative cooler ahead of the A/C heat exchanger.
    Possibly when used this way, the increased cooling more than overcomes the reduced airflow. I would be reluctant to use them as filters only just to keep the heat exchanger clean without having a much better idea of how much they restrict the airflow.
    SMA SB 3000, old BP panels.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #21
    Re: will shading outside HVAc compressors help at all?

    if the filters do their job then the airflow would become restricted even if they would allow full flow when new, which i don't believe that they would allow full airflow unless the area to be filtered is made to be much larger to compensate for the restrictions, new or otherwise.

    yes, i was thrown off a bit by the term blanket instead of the correct term of filter being used, but my point does still stand. i should also point out that the filter does not shade the entire area as it is only on the air intake.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #22
    Re: will shading outside HVAc compressors help at all?

    I'm going to hook up my 500 gallon rain water tank to this shallow well pump
    http://www.harborfreight.com/1-horsepower-shallow-well-pump-with-stainless-steel-housing-68387.html
    Which costs $144. I'm going to buy a filter kit for it so all the dead bugs and debri that end up in my rainwater tank don't mess it up.

    My well water is not super hard, but I do notice white calcium deposits on my tea pot. And if you are spraying anywhere from 100gallons to 500 gallons per week on a compressor I think rain water is the best way to Avoid mineral deposits.Does anyone have real usage figgures on the Gallosn of water you go through? Obviously depends on the weather, a bit, but I've yet to find any feedback from users, just the companies selling these gizmos.

    I can get 250 gallon tanks off craigs list for $40 to $100 dollars . Of course you need a trailer to get them home.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #23
    Re: will shading outside HVAc compressors help at all?
    rollandelliott wrote: »
    I'm going to hook up my 500 gallon rain water tank to this shallow well pump
    http://www.harborfreight.com/1-horsepower-shallow-well-pump-with-stainless-steel-housing-68387.html
    Which costs $144. I'm going to buy a filter kit for it so all the dead bugs and debri that end up in my rainwater tank don't mess it up.

    My well water is not super hard, but I do notice white calcium deposits on my tea pot. And if you are spraying anywhere from 100gallons to 500 gallons per week on a compressor I think rain water is the best way to mineral deposits. Does anyone have real usage figgures on the Gallosn of water you go through? Obviously depends on the weather, a bit, but I've yet to find any feedback from users, just the companies selling these gizmos.

    I can get 250 gallon tanks off craigs list for $40 to $100 dollars . Of course you need a trailer to get them home.

    tone it down. we are going by the original subject matter in the thread title originated by you and the yelling (large bold letters) is misdirected to us on the forum.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #24
    Re: will shading outside HVAc compressors help at all?

    No real word figures, but that looks like serious over kill if your looking at the cooling mister things I've seen for AC units, unless your loading a gravity feed system.

    Put a screen over your rain water entrance and you'll have much fewer bugs and such, pretty much required if you don't want to bread mosquitoes.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #25
    Re: will shading outside HVAc compressors help at all?

    As it happens, I have a Penguin air conditioner which is designed to run using water to accentuate the cooling capacity (evaporates water which is replaced from a reservoir).
    It is completely impossible to quantify the effect in standard use as it is highly dependent on both temperature and humidity. At 12,000 btu's it can cool the whole 1400 sq. ft. house even in August @ 30C. Runs almost constantly to do so, but it takes the edge off (I don't try for refrigerating the livingroom :p). It will go through eight litres on such a day.

    But that is a unit designed to work that way. Adding moisture to a standard A/C to improve the heat radiating is likely to be less efficient. Under some circumstances it might make it worse.

    Rolland, I think you answered your own question with this: "but I've yet to find any feedback from users, just the companies selling these gizmos."
    That kind of says it all, really. :roll:
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #26
    Re: will shading outside HVAc compressors help at all?

    Heard back from a guy who lives In Wisconsin.
    He has one 275gallon rain tote and an extra 110 gallon of rain barrels. He said some times he can go a few days on his water supply. He told me 12 gallons an hour is typical with rainbird misters that dont' create a fine mist. That's 96 gallons if you run the AC 8 hrs a day, about 700 gallons a week!

    His usage seems to be more than what the companies project. Of course it all depends on how many nozzles you have, how hot it is, what your thermostat it set to.

    As far as not much feed back I think it is mostly because it is a huge hassle to make a rain water collection system and people are generally fine with paying through the nose in the long run if they have a cheap cost up front. And if you are using tap water it is hard to measure how much you use. There are two commercially available products and one of them is made poorly $100 according to reviews and the other one is very expensive $500. leaving most systems to the DIYer.
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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #27
    Re: will shading outside HVAc compressors help at all?

    Yes. An air conditioner can only generate a certain amount of temperature differential between the condenser (outside) and evaporator (inside) coils. If you cool down the condenser you will cool the evaporator. When I was working in the oilfield in the Peruvian jungle, we lived in huts with window units exposed to sunlight. On hot days (every day was hot!) we would take turns going out and throwing a bucketful of water on the A/C every half hour or so. You could feel the output air temperature drop almost immediately.
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #28
    Re: will shading outside HVAc compressors help at all?

    Why don't A\C builders take the condensate from the evaporator, and direct it to cool the condenser? It is after all pure water so there should be little mineral build up on the coin, and it should give some increase in efficiency?

    Tony
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #29
    Re: will shading outside HVAc compressors help at all?

    It sounds like that is what the newer window units are doing--Slinging (oops) condenser onto the evaporator (from earlier posts) and sometimes making a leaky mess.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #30
    Re: will shading outside HVAc compressors help at all?
    BB. wrote: »
    It sounds like that is what the newer window units are doing--Slinging condensate onto the evaporator (from earlier posts) and sometimes making a leaky mess.

    -Bill

    Window units have been doing that for a long time, but it has been particularly necessary to get a high energy efficiency rating. Even single-piece portable A/Cs like the Pinguino have been doing the same thing. The exhaust air from the condensor, as pumped out the window, is humid. One downside is that you have to be careful when moving the unit after it has been running for awhile.
    On the other hand a mini-split does not have that option unless there is a way to get the condensate drain to the outside unit.
    SMA SB 3000, old BP panels.
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  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
    #31
    Re: will shading outside HVAc compressors help at all?

    Some of the Cool n save reviews metion that it sprays so much water that it turned thier lawn into a muddy mess. I can just image a poorly drained lawn turning into a pond with 100 to 700 gallons of water being poured on it weekly.

    Ideally you'd have a HUGE drain pan under neath the units and a small pump to move the water back to the rainwater tank.
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