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  • CodeSection
    Junior Member
    • May 2015
    • 6

    #1

    Will a 22.68 kW DC System Produce 42,663 kWh Annually?

    I'm a little confused by another thread of 24 kW and the amount of kWh supposedly it produced and what the person's actual need was.

    My bid shows 22.68 kW DC indicating it should produce 42,663 kWh. Does that sound right? Currently, my monthly average usage is 3553 kWh with the total annually being 42,640 kWh. History shows usage slightly going up. Current system design is to cover 100% of usage.

    There will be three arrays each sized 7.56. A total of 81 LG280 panels. A total of 81 M250 Enphase microinverters. At the time of the bid, one array angle was 30 and the two others angle was 15. Now that I have a different location, all three array angles can be 30. So, if the angles of the two were increased from 15 to 30, would that mean I would not need as many LG280 panels?

    For what it is worth, my pool pumps have been replaced with IntelliFlo Variable Speed Pumps. I have been replacing all my lights with LED lights as they burn out and need replacing. The biggest user of electricity come from several AC units. Heat is generated through several water heaters that use natural gas and have coils with hot water running through the coils that are located inside each of the AC units. The AC fans blows air over the coils to produce heat to the house. When in the heating mode, the thermostats open valves letting water to circulate throughout the system and at the same time turn on the fan.

    I appreciate all comments and help. Thanks!
  • bcroe
    Solar Fanatic
    • Jan 2012
    • 5209

    #2
    Originally posted by CodeSection
    I'm a little confused by another thread of 24 kW and the amount of kWh supposedly it produced and what the person's actual need was.

    My bid shows 22.68 kW DC indicating it should produce 42,663 kWh. Does that sound right? Currently, my monthly average usage is 3553 kWh with the total annually being 42,640 kWh. History shows usage slightly going up. Current system design is to cover 100% of usage.

    There will be three arrays each sized 7.56. A total of 81 LG280 panels. A total of 81 M250 Enphase microinverters. At the time of the bid, one array angle was 30 and the two others angle was 15. Now that I have a different location, all three array angles can be 30. So, if the angles of the two were increased from 15 to 30, would that mean I would not need as many LG280 panels?

    For what it is worth, my pool pumps have been replaced with IntelliFlo Variable Speed Pumps. I have been replacing all my lights with LED lights as they burn out and need replacing. The biggest user of electricity come from several AC units. Heat is generated through several water heaters that use natural gas and have coils with hot water running through the coils that are located inside each of the AC units. The AC fans blows air over the coils to produce heat to the house. When in the heating mode, the thermostats open valves letting water to circulate throughout the system and at the same time turn on the fan.

    I appreciate all comments and help. Thanks!
    It sounds like you have already done a lot toward energy conservation. 42,640 kWh is a huge annual
    usage, much larger than mine, and I heat electrically up north. Big electric motors running a lot will do
    that. It would be good to put some numbers on the pumps and AC actual use.

    I am also generating 100% of usage; haven't bought a KWH in 14 months. Some will say that's not
    the best ROI, but there is a lot of satisfaction of being able to operate equipment and knowing the
    electric bill isn't increasing. The addition that has really improved the overall efficiency is replacement
    of my ancient AC unit with the latest high efficiency heat pump, doing most heating & cooling directly
    from the sun. This upgrade was less than 10% my investment in solar. If AC is a major part of your
    consumption, you might want to consider that. I managed with a smaller air to air unit, but with your
    high outside temps and high usage, a much more efficient (and much more expensive) air to buried
    coil heat pump might be right. Bruce Roe

    Comment

    • DanS26
      Solar Fanatic
      • Dec 2011
      • 987

      #3
      Run your proposed setup thru PVWatts here:

      Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations


      Should give you a handle on probable production. Some people say calcs are 5 to 10% low, but my experience has been right on.

      Comment

      • HX_Guy
        Solar Fanatic
        • Apr 2014
        • 1002

        #4
        Ran a quick PVWatts for you and it's showing 41,550kWh production based on 8% system loses, maybe it'll be less because of the micros...and if I change the panel type to Premium (is LG280 considered premium?) then it shows 42,846...so I guess you're right in that ballpark.

        Comment

        • CodeSection
          Junior Member
          • May 2015
          • 6

          #5
          Thanks guys, I appreciate the help.......

          I was thinking about obtaining 100% coverage for actual use so that the annual degradation of .7 would be offset. Perhaps I should recalculate since the first 500 kWh each month is about .0225 less than the maximum charge. It might be worth comparing cost of the system at 100% vs 95% or so.

          Again, thank you to all for posting!

          I hope your rest of the week is a good one!

          Comment

          • Alisobob
            Banned
            • Sep 2014
            • 605

            #6
            Originally posted by bcroe
            ....but there is a lot of satisfaction of being able to operate equipment and knowing the
            electric bill isn't increasing.

            I didnt go solar, to sweat the small stuff.

            I went solar to run the A/C as damm well much as I please....

            Comment

            • J.P.M.
              Solar Fanatic
              • Aug 2013
              • 15015

              #7
              Originally posted by Alisobob

              I didnt go solar, to sweat the small stuff.

              I went solar to run the A/C as damm well much as I please....
              You're busted - in the sense your clairvoyance is out of the bag. I was just going to ask why if it was your concern for the planet or the ability to stay cool and have low elec. bills.

              Comment

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