Iced up panels - must resist temptation to thump them!

peakbaggerpeakbagger Solar Expert Posts: 341 ✭✭✭
I had an extended icing event over Sunday and Monday, compared to other nearby areas, I didnt get it bad but one result is three sets of panels with 1/4 to 3/8" think of ice on them . Two of the arrays are at 30 degrees off vertical (my normal winter setting) and my other array is closer to 30 degrees off horizontal on a second floor roof. I pretty well have written off the roof panels for the winter in northern NH due to snow cover but generally my other two arrays are easy to clean off after a snow storm. Its supposed to be cooling down today from 20 degree F to 10 degrees but at least it will be sunny.

Much as its tempting to try to break off the ice, I plan to let the sun melt them off, as the ice is currently very tenacious in its grip. It will be interesting to see how much power I generate in the meantime, the ice on the winter angle panels is fairly clear but the roof panels are milky white. My set ups are grid tied with net metering so its not critical but I expect off gridders would be even more motivated to get them clean. I did think of using wood ashes but expect it would just make a major mess.

Comments

  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Iced up panels - must resist temptation to thump them!

    Here in snow and ice covered Nova Scotia I have no buildup whatever on my vertically mounted panels. And as soon as the sun decides to once again show it's face, I'll get lots of production from the sun low on the horizon, greatly added to by reflection off the snow covered ground. In fact, Winter production can be higher than summer production when the sun shines. I've long since given up fighting with nature trying to keep my panels clean. Used to think they needed to be tilted up a bit for Winter, that turned out to be a mistake, and now I'm as panel care free in Winter as in Summer. Of course come Spring, the panels get tilted up to kiss the sun :)
  • northernernortherner Solar Expert Posts: 492 ✭✭✭✭✭✭
    Re: Iced up panels - must resist temptation to thump them!

    I've had freezing rain on my panels, but nothing what you guys back east just received. I find it usually will melt off when the sun comes out, so no big deal. I find they often collect a skiff of snow after a snow storm, so I have mounted a broom on a long pole and give them a quick sweep in the morning if needed. I have my panels oriented about 15 degrees off vertical, and I tilt them down a bit in summer.

    I find that my power input at noon cold, clear day in midwinter is close to the same (~10% less) than at noon on a hot summer day. The sun is very low here at about 56 deg latitude in midwinter, so any haze or high cloud in the atmosphere affects the output significantly. On the shortest day this winter, I had clear sunshine for almost the entire day (bit of cloud early am) and I received 8.7 kwh from a 2.8 kw array. Not bad for midwinter! The 2 worst months for clouds in my location of northern Alberta are November and December, so things will be getting better here soon.
  • Ralph DayRalph Day Solar Expert Posts: 986 ✭✭✭✭
    Re: Iced up panels - must resist temptation to thump them!

    The storm Wayne had was here first. It left almost 1" of ice on my house system panels and 10kw fit panels. A brushing took off the dusting of snow (reflective) and increased production, but the ice is still on the house system. The fit panels are mostly clear, but even with 80% coverage with ice they still produced 7-9kw. Clear ice doesn't seem to be a big problem for pv production, at least not a big enough problem to risk damage from trying to clear it off.

    Just snow will cut production to zero, so brushing that off is certainly worthwhile...but ice I leave alone. Usually there's a warm spell after a freezing rain event, but not this time. Trees are still touching the ground in the woods making walking or skiing impossible (edges of the trail trees are drooping accross themselves to the ground).

    |Ralph
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Iced up panels - must resist temptation to thump them!

    if you have any concern of ice for any reason it should be for the weight of it. ice doesn't melt very quickly and subsequent weather systems blowing through could add to what is already there. 1 inch isn't terrible for pvs, but it takes long for that to disappear.

    i should also add that sliding ice could damage pvs under the right circumstances.
  • peakbaggerpeakbagger Solar Expert Posts: 341 ✭✭✭
    Re: Iced up panels - must resist temptation to thump them!

    A sunny day melted them off. Its interesting, the panels that are hung off the front wall of the house melted the quickest, I expect the sun reflects off the snow and the heats the wall behind the panels and sets up a convective heat up behind the panels. The panels melted from the top down. The roof mounts took awhile longer but the ice storm had also exposed some roof shingles so once they started heating up in front of the panels that got under the panels and got some heat on the backside. The pole mount took the longest (and was of the most concern), nothing nearby to heat the panels up and most exposed to wind.

    Glad they melted as its 1 degree F out with wind chill warning today.
  • halfcrazyhalfcrazy Solar Expert Posts: 720 ✭✭✭
    Re: Iced up panels - must resist temptation to thump them!

    peakbagger
    Just up the road from ya a poke. We had 3/4 of an inch of Ice on ours. I was surprised though there was just enough sleet under them that some good thumping on them with my roof rake set sheets of ice sailing down the roof. Interesting storm to say the least. At one point 1/4 of our residents in Maine where without power. It is still probably close to 100,000 residents without. Gonna be into the weekend or even next week on the restoration they say. Going to be a cold old fashioned Christmas for some.

    Ryan
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Iced up panels - must resist temptation to thump them!

    here's a yahoo article on the ice storm. i suspect after this more may show interest in backing up their power.

    http://news.yahoo.com/thousands-want-christmas-electricity-060502624.html
  • techntrektechntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: Iced up panels - must resist temptation to thump them!
    niel wrote: »
    i suspect after this more may show interest in backing up their power.

    You'd think by now most people would have backup power and other supplies, but even after the big storms in the last decade most still insist on relying on others for everything.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • halfcrazyhalfcrazy Solar Expert Posts: 720 ✭✭✭
    Re: Iced up panels - must resist temptation to thump them!

    Yep we have some one in the local newspaper suggesting that the state give away generators to all remote family's so they can be prepaired next time..
  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Iced up panels - must resist temptation to thump them!
    halfcrazy wrote: »
    Yep we have some one in the local newspaper suggesting that the state give away generators to all remote family's so they can be prepaired next time..
    Then there would be a bunch of generators on Craig's List. They'd never have any fuel for it and if they used it would never have any maintenance on it. We call that a " Good idea, gone bad " ....... lol
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Iced up panels - must resist temptation to thump them!
    Then there would be a bunch of generators on Craig's List. They'd never have any fuel for it and if they used it would never have any maintenance on it. We call that a " Good idea, gone bad " ....... lol

    It would turn into a sad state of affairs and I have to agree with your comments. Very few would be those who would appreciate, treasure and look after their free to them generators. It's hard enough to get people who pay for their own generators to look after them :(
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Iced up panels - must resist temptation to thump them!
    halfcrazy wrote: »
    Yep we have some one in the local newspaper suggesting that the state give away generators to all remote family's so they can be prepaired next time..

    haha, next thing he'd suggest is the state buying the gasoline for them too. what is stopping him from getting his own generator, even an el cheapo? of course he doesn't realize that the gas stations won't have power either meaning no gasoline will be available.:roll:

    maybe we should tell our states to provide solar power systems for us too along with doomsday shelters, bug out vehicles (electric of course), and rems?;)
  • bill von novakbill von novak Solar Expert Posts: 891 ✭✭✭✭
    Re: Iced up panels - must resist temptation to thump them!
    halfcrazy wrote: »
    Yep we have some one in the local newspaper suggesting that the state give away generators to all remote family's so they can be prepaired next time..

    Be better off giving people instructions to tap off a hybrid vehicle's battery for emergency power. People tend to maintain their cars, and tapping off some power is pretty simple.
  • techntrektechntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: Iced up panels - must resist temptation to thump them!
    It would turn into a sad state of affairs and I have to agree with your comments. Very few would be those who would appreciate, treasure and look after their free to them generators. It's hard enough to get people who pay for their own generators to look after them :(

    All true. Someone in my family who is otherwise good with engines refused to take my advice to run his genset once a month. Didn't want to hear about dried out seals, carb issues, or needing to flash the field. "It will be fine". Right.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • RandomJoeRandomJoe Solar Expert Posts: 472 ✭✭✭
    Re: Iced up panels - must resist temptation to thump them!

    I had 1/2-3/4" of ice on my panels after the freezing rain here. A couple of cloudy and COLD days later we finally got some sun and I saw my system was producing power just fine. A little later I went outside and looked up - they were still coated with ice! So apparently clear ice doesn't block the panels too much, really surprised me they were performing as well as they did.

    A day or two later, when it finally warmed enough for the ice to thaw and slide off - the effect was rather humorous. (Dangerous too, fortunately I wasn't outside!) The noise of those sheets of ice sliding down the roof then smashing to bits on the back patio drove my cats NUTS! :p They didn't know WHICH way to run! (And now I see I could probably use some of those ice-breaker doodads I've seen on sloped roofs on commercial buildings...)
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