Agenda - 09-04-2014 - 6a - Laserfiche WebLink

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68 1 For Mr. Wallace, you mentioned the sound levels that are put out by the inverters, and I 2 believe the figure was on the order of by the time it hit the house it was 45 db. Two questions 3 on that; one, do you have any information on the spectral characteristics of the noise that comes 4 out of the inverters? There is a huge difference between a 45 db sound level at 60 hertz and at 5 480. It's a subjective way to figure out, is this a 45 db that is going to keep you up at night, or 6 can you ignore it. The second thing is; do you know the weighting algorithm that was used to 7 come up with that 45 db figure, so that if it wishes to be verified later, or citizens wish to make 8 measurements, they will know how set their noise meters? 9 10 Mike Wallace: The answer to the second question; I do not. That would have to come from 11 the manufacturers of the inverters. The answer to the first question is; there is that out there 12 published. We do have some of it, and I can get that for you, so you can see what frequencies 13 these db's are coming at. 14 15 Pete Hallenbeck: That would be great. The planning board meets the first Wednesday of the 16 next month. And for Mr. Cleveland; are these panels gonna—are they amorphous silicon, or it 17 is pure crystalline silicon? Do you know. 18 19 Tommy Cleveland: No, they are not amorphous. I'm not sure if they are poly-crystalline or 20 mono-crystalline, but they are—those two are very similar, and amorphous is somewhat 21 different. They are not amorphous. 22 23 Pete Hallenbeck: Okay, I'm just curious if you could find out. It's always interesting to see with 24 the trade-offs people are making on panel costs versus the area of the farm. And as I'm sure 25 you know, the poly-silicone crystal —well mono-crystal: smallest, best efficiency; poly: higher; 26 amorphous: higher still. So, I was just curious to see what that trade-off was. 27 28 Tommy Cleveland: Amorphous silicon is significantly less efficient, and there is very little 29 amorphous —sorry, as far as area. I thought you were referring to efficiency, and you said size. 30 So, you were correct. 31 32 Pete Hallenbeck: If you can find out exactly what kind of panel it is, that would be interesting. 33 The second thing is, with regard to the glare, do you know what the Brewster angle is on the 34 cover glass, because that would pretty much determine the glare the residents would see, who 35 are due west of the site? 36 37 Tommy Cleveland: I don't know that, but I could reference you to Sandia National Labs and an 38 FAA glare calculator built specifically for airports and solar sited at airports. They've got a 39 calculator where you can put in, on a Google earth map, the location of the panels and a 40 location of interest and determine if there is glare any hours of the year. 41 I don't like the Brewster angle for those - 42 43 Pete Hallenbeck: I'd still like to see that Brewster angle. I have panels at home. From 44 mowing around during different times of the day, I have some idea of what the glare is. But the 45 situation that we're talking about here is one that comes very close to the equinox. The sun is 46 rising. It's going to hit the panels, and it doesn't matter what the coatings are. As soon as that 47 angle is under the Brewster angle for the glass, it's going to bounce off, and that will be the 48 glare. So, that would be an interesting number that would let us be able to figure out how many 49 days per year there will be glare during the morning. 50