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4.4 kW Solar PV Grid Tie System in San Diego

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  • #16
    I opted for horizontal mounted panels on my horizontal roof. I could have tilted them but they would have then needed to be spaced and mounting would have been more expensive. By having them flat I lost some efficiency but system cost was cheaper and enabled me to add an extra panel. It was a swings and round-abouts sort of thing...or six of one half dozen of the other, if you get my drift? I think my signature has a link to my system and there are some pics I posted on PVOutput. Mounting horizontally also looked better and they are not viewable from the street.
    [url]http://tiny.cc/m8ex0x[/url]

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    • #17
      Originally posted by UkiwiS View Post
      I opted for horizontal mounted panels on my horizontal roof. I could have tilted them but they would have then needed to be spaced and mounting would have been more expensive. By having them flat I lost some efficiency but system cost was cheaper and enabled me to add an extra panel. It was a swings and round-abouts sort of thing...or six of one half dozen of the other, if you get my drift? I think my signature has a link to my system and there are some pics I posted on PVOutput. Mounting horizontally also looked better and they are not viewable from the street.
      https://goo.gl/photos/T7P3drhr5RL4rNob6
      [url]http://tiny.cc/m8ex0x[/url]

      Comment


      • #18
        Originally posted by UkiwiS View Post
        I opted for horizontal mounted panels on my horizontal roof. I could have tilted them but they would have then needed to be spaced and mounting would have been more expensive. By having them flat I lost some efficiency but system cost was cheaper and enabled me to add an extra panel. It was a swings and round-abouts sort of thing...or six of one half dozen of the other, if you get my drift? I think my signature has a link to my system and there are some pics I posted on PVOutput. Mounting horizontally also looked better and they are not viewable from the street.
        I don't mean this to sound like I'm raining on your parade, but was a likely increase in frequency of cleaning for horizontal panels one of the considerations ?

        Comment


        • #19
          Originally posted by J.P.M. View Post
          I don't mean this to sound like I'm raining on your parade, but was a likely increase in frequency of cleaning for horizontal panels one of the considerations ?
          Yes it was a consideration but I had no idea how often they'll need to be cleaned horizontal vs tilted. We get a lot of black crap deposited everywhere....not sure if it's from I5 or from the traffic to/from Lindberg. If you are going to rain, please rain on my roof bit not my parade.
          [url]http://tiny.cc/m8ex0x[/url]

          Comment


          • #20
            Originally posted by UkiwiS View Post
            Yes it was a consideration but I had no idea how often they'll need to be cleaned horizontal vs tilted. We get a lot of black crap deposited everywhere....not sure if it's from I5 or from the traffic to/from Lindberg. If you are going to rain, please rain on my roof bit not my parade.
            Thank you. Other readers not yet solar equipped may well benefit from your experience.

            Comment


            • #21
              Originally posted by albert436 View Post
              Still haven't gotten a very definitive idea of how much additional cost it is to tilt mount panels.

              Anyone have an answer, a range of course, other than "it depends", or "I would think it would be a lot" ?
              G'Day Albert,

              In Oz we allow about $200 per kilowatt, for angle frame kit and bit of extra labor to install it, so its probably similar or a little bit more in the states, hope thast helps.

              Comment


              • #22
                Originally posted by albert436 View Post
                Interesting thread. I was jst curious about the type of roof you have but I couldn't find a pic of one very easily, even on their website, just a long description of it.

                Thanks for the links on the tilt mounts or "wedge mounts" as the one company calls them, at $0.12/WDC, I wonder why they price them out like that, I would think they'd be priced out at some combination of panel and size parameters.

                What do you reckon is the thinking behind it ?

                But in any case $0.12/WDC doesn't sound like so very much WDC is what we are talking about here, right ? And the regular mounts would cost something anyway so just saying.

                Anyway it is a whole interesting aspect of the subject, easy to over look for those who have roofs which are favorably oriented etc.





                ps. eh, why aren't my smilies working ? <----- manually placed smiley

                Hey Albert,

                Jumped up on my roof today to take a few pictures for you. Man it got dirty in a year so that's good to know if I was planning on doing Horizontal mounted panels.

                https://goo.gl/photos/1XrJbs5RGEL9DDJn6

                Ya they seem cheaper than having Duro-Last come back out and make all kinds of punctures in my roof... Just talked with an structural engineer and he informed me that it was not recommended. My house was built in 1928...

                Comment


                • #23
                  Originally posted by thejq View Post
                  That's nice roof. You definitely need to get some professionals that have dealt with it before. Last thing you want to is to go cheap and somehow damage it in the installation process.
                  Ya exactly. Also using a non-Duro-Last authorized roofer voids the 20-year warranty which is why I went with this roof in the first place...

                  Comment


                  • #24
                    Originally posted by DanS26 View Post
                    Does the AHJ allow ballast mounted arrays on horizontal roofs in the North Park area?

                    I know SD does not get much rain but to put all those punctures in a horizontal roof just makes me cringe.
                    I'm not sure. I decided not to go with a ballast system after talking with a structural engineer today... Looks like I'm back to the Prosolar SolarWedge Roof System...

                    Comment


                    • #25
                      I really like the idea of not having them seen from the road! I may have to consider this as my home is on a Mills Act street. I have not applied however and was not planning to due to solar but this may work...

                      Comment


                      • #26
                        Originally posted by J.P.M. View Post
                        Thank you. Other readers not yet solar equipped may well benefit from your experience.
                        So how frequently do you end up cleaning them to keep them at their peak performance?

                        Comment


                        • #27
                          Originally posted by rfay View Post
                          So how frequently do you end up cleaning them to keep them at their peak performance?
                          "Peak" may not be the most fitting word to use, particularly with a horiz. orientation. When and how to clean a solar panel, like most of solar energy technology, is far from an exact science. One consideration of many, is orientation. It may be likely that in many locations, an array at a high(er) tilt angle (say 45 deg.) may be kept cleaner by wind and rain than a lower (say, 20 deg. to the horiz. partly due to gravity and a greater washing potential of increased runoff velocity. In the case of (mostly) horizontal panels, rain water or snow melt will tend to stay put as will morning condensate from fog/dew which, as you know, is pretty common around you. During the day, the horizontal panel will act something like an evaporation pond, or a settling pond, leaving all the stuff that came with the moisture as residue. Those who have tilted panels and have noticed the bottom 6" -12" or so of the panels getting dirtier quicker can appreciate that a horiz. panel is that way over a greater portion of the panel, perhaps most or all of it, only worse and perhaps getting that way faster. Next night - same thing, but with no or little runoff from gravity...................Another possible consideration is how to get at a panel in the middle of a horizontal array. Probably a lot of the accumulated stuff can be hosed off if attended to fairly quickly after deposition. In some case, perhaps yours, being near the airport and freeways, the stuff deposited with moisture or by itself falling out of the air (tire dust ?, dumped fuel ?, other ??) may bond or otherwise interact with the panel glass, perhaps affecting any antireflective coating as well, perhaps not, but perhaps more so than tilted panels some SLOIGHT mechanical action beyond high velocity spraying may be necessary. If you can't get at the panels effectively, they may not get as clean as desired................. I am not extremely well versed in panel fouling mechanisms, but I'd be surprised if any one is, this being a very imprecise matter..........................FWIW, and for my situation only, after and during a lot of ongoing measurement, I believe my array's performance deteriorates very approximately at a rate of SOMETHING like 1% per week in the absence of any measureable rain. However, my array is at about an 18-19 deg. tilt, and I'm in a fairly benign, semi rural and mostly dust free area.................. related to all this in an anecdotal way perhaps, I spend some time in Borrego Springs. (For those unfamiliar, it's about as hot/dry as Phoenix, but about as quiet and populated as a tomb) I had the opportunity to observe a horizontal array on a residence that had been operating for several months. I did not get to talk to the owners, but the architect for the home, who specified the array and design seemed rather proud of the effort, mostly it seems for the sole reason that it was out of sight on a flat roof hidden by parapets. There was about 1/16" of caked desert over most of the array, apparently left over from the rainy season. Something like half the array was impossible to get at. What I describe is probably a rather extreme case, but it may be a matter of degree and time, rather than an unusual result..................Bottom line, and my opinion ONLY, the probability of a horizontal array needing more frequent cleaning is, IMO only, greater than for a tilted array. Also, IMO only, the probability of long term problems due to excess moisture and accumulated dirt is greater for a horiz. array than for a tilted array.

                          Comment


                          • #28
                            Originally posted by J.P.M. View Post
                            "Peak" may not be the most fitting word to use, particularly with a horiz. orientation. When and how to clean a solar panel, like most of solar energy technology, is far from an exact science. One consideration of many, is orientation. It may be likely that in many locations, an array at a high(er) tilt angle (say 45 deg.) may be kept cleaner by wind and rain than a lower (say, 20 deg. to the horiz.) partly due to gravity and a greater washing potential of increased runoff velocity. In the case of (mostly) horizontal panels, rain water or snow melt will tend to stay put as will morning condensate from fog/dew which, as you know, is pretty common around you. During the day, the horizontal panel will act something like an evaporation pond, or a settling pond, leaving all the stuff that came with the moisture as residue. Those who have tilted panels and have noticed the bottom 6" -12" or so of the panels getting dirtier quicker can appreciate that a horiz. panel is that way over a greater portion of the panel, perhaps most or all of it, only worse and perhaps getting that way faster. Next night - same thing, but with no or little runoff from gravity...................Another possible consideration is how to get at a panel in the middle of a horizontal array. Probably a lot of the accumulated stuff can be hosed off if attended to fairly quickly after deposition. In some case, perhaps yours, being near the airport and freeways, the stuff deposited with moisture or by itself falling out of the air (tire dust ?, dumped fuel ?, other ??) may bond or otherwise interact with the panel glass, perhaps affecting any antireflective coating as well, perhaps not, but perhaps more so than tilted panels some SLIGHT mechanical action beyond high velocity spraying may be necessary. If you can't get at the panels effectively, they may not get as clean as desired................. I am not extremely well versed in panel fouling mechanisms, but I'd be surprised if any one is, this being a very imprecise matter..........................FWIW, and for my situation only, after and during a lot of ongoing measurement, I believe my array's performance deteriorates very approximately at a rate of SOMETHING like 1% per week in the absence of any measureable rain, or cleaning. However, my array is at about an 18-19 deg. tilt, and I'm in a fairly benign, semi rural and mostly dust free area.................. related to all this in an anecdotal way perhaps, I spend some time in Borrego Springs. (For those unfamiliar, it's about as hot/dry as Phoenix, but about as quiet and populated as a tomb) I had the opportunity to observe a horizontal array on a residence that had been operating for several months. I did not get to talk to the owners, but the architect for the home, who specified the array and design seemed rather proud of the effort, mostly it seems for the sole reason that it was out of sight on a flat roof hidden by parapets. There was about 1/16" of caked desert over most of the array, apparently left over from the rainy season. Something like half the array was impossible to get at. What I describe is probably a rather extreme case, but it may be a matter of degree and time, rather than an unusual result..................Bottom line, and my opinion ONLY, the probability of a horizontal array needing more frequent cleaning is, IMO only, greater than for a tilted array. Also, IMO only, the probability of long term problems due to excess moisture and accumulated dirt is greater for a horiz. array than for a tilted array.
                            I corrected some grammar /spelling from the orig. text. (I still can't edit the normal way)

                            Comment


                            • #29
                              Originally posted by J.P.M. View Post
                              I corrected some grammar /spelling from the orig. text. (I still can't edit the normal way)
                              Great info thank you! I do like the idea of it being out of 'sight' I'l need to do some more research on the exact efficiency of a horizontal array vs 10° tilt (which is what I would need anyhow)...

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                              • #30
                                Run PVWatts at both orientations and ratio the two.

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