Panel Snow and Ice

Mangas
Mangas Solar Expert Posts: 547 ✭✭✭✭
in Advanced Solar Electric Technical Forum #1
Trying to clear my snow and ice covered panels today, I was wondering if there exists a safe, best practice de-icer product approved for solar panels which won't degrade the seals, wiring or glass membrane?
Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #2
    Re: Panel Snow and Ice

    The sun? LOL

    Seriously,, My intuition would be that windshield washer anti-freeze would be fine.. In proper concentration doesn't harm laminated glass or windshield gaskets or paint work.

    Tony
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  • Ecnerwal
    Ecnerwal Solar Expert Posts: 101 ✭✭
    #3
    Re: Panel Snow and Ice

    Warm water? If you happen to have gravity feed so you can use a lot and not count the power loss (no pump needed), even "cold" water (typically 45 or so) out of a spring will melt snow/ice quite nicely, and with no adverse chemistry to deal with (either on the panels, or plants, etc. where it drains off to.)

    MHO panels in snow country should be able to be put/adjusted vertical or near vertical for the winter - with snow reflection power "lost" from wrong angle is generally not "lost" in practice, and power lost from not having sun get through the snow on the panels is lost in practice. If the adjustment is easy, you can flatten them out for sunny days.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    Re: Panel Snow and Ice

    Regarding windshield deicer--many contain Methanol--a serious poison. Not something I would recommend splashing a lot around on your panels.

    A broom and sun is probably your best bet--but listen to Tony, he actually lives where it snows--I do not.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #5
    Re: Panel Snow and Ice

    I have mixed feelings about warm water--The panels should probably withstand the thermal shock of warm water...

    But, in general, thermal shock is a great way to do accelerated testing of your panels. I used accelerated thermal cycling to test hard disk drives in another life--the good ones lasted well. The bad ones failed in one to two weeks.

    Glass is not a great thermal conductor, so it will dramatically expand while the solar cells underneath will expand more slowly (as the warmth works it way down--and there may be a clear adhesive membrane between the glass cover and cells below, adding more thermal insulation between glass and cell).

    I have no idea if the differential expansion is enough to case enough stress/thermal cycling to cause early life failures (for example, nobody here has ever reported problems with cold water on hot panels for washing/seeing if output energy is improved with water cooling)... But, I avoid doing it to my panels--just in case.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #6
    Re: Panel Snow and Ice

    Bill,

    Thanks for the plug,,, but don't listen to me RE: any chemical or anti-freeze! I only suggest that windshield anti freeze might work, but merits some other research. In my case,, a broom is all I ever use. My wall mounts I can scrape if they ice up with a windshield scraper,,,although I can't ever remember doing so. The roof tops, need a sweep now and again, and then they melt off quite quickly. A quirk of the way I have mounted them, is that they extend up above the peak. ( the bottom 1/2 of the panels are on the roof, the tops in the free air above the peak if that makes sense). Because of of the quirks of the wind, they don't collect too much snow too often. Warm, wet snow in the fall and the spring is the worse if we get a big dump. Mid-winter snow just blows off.

    Tony

    Ps I agree that warm water sounds like a bad idea! The thermal shock could be considerable. In my case, say it is bitter cold, say -35F, and I pour warm water at say 70F. The thermal shock would be pretty good, but in this case it would freeze like a brick making a bad situation way worse!
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  • Mangas
    Mangas Solar Expert Posts: 547 ✭✭✭✭
    #7
    Re: Panel Snow and Ice

    Thanks everyone.

    I'm an old desert rat so snow is rare for us. I get a little impatient.

    I use the broom and wait for the sun too, but thought I could hustle it up a bit to keep the batteries ahead of the latent charge. I am too squeemish to use a scraper like Tony.

    Bill's conservative and careful position regarding thermal shock to the panels makes a lot of sense to me.

    Panel manufacturers could contract manufacture a best practice formula and market a product like that. I mean if you can sell bottled water?
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #8
    Re: Panel Snow and Ice

    Almost as soon as the panels see the sun, (some portion) there becomes a layer of melt water under the ice, and scraping is really just sliding the ice off. As I said before,, when it is really cold this is really not a problem. When ice forms near freezing, the melting is pretty quick.

    Tony
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #9
    Re: Panel Snow and Ice

    Mechanical removal (i.e. broom) is best if possible. If you've got a real frozen-on condition try plumbing antifreeze - the pink stuff sold for winterizing RV systems. It is pretty much non-toxic to wildlife and can be applied 'cold'. Should work in all but the most vicious weather.
    Mine are at such a steep angle (72°) that it is never a problem for very long.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #10
    Re: Panel Snow and Ice

    a broom is all i have ever used and i accept some times of diminished production due to snow and ice. i won't risk my panels for a few watt-hours.
    i do feel that during a bad ice storm ir freezing rain that weighs down significantly on the pvs that i may be inclined to try removing some of that weight. i never got to that point of feeling the need to try something and i wonder just how i would go about it. throwing water onto it, warm or not, would possibly refreeze and make matters worse. heat tape may be a possibility only if i feel the need to save the pvs. getting it onto the pvs would be another dilemma.
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  • Mangas
    Mangas Solar Expert Posts: 547 ✭✭✭✭
    #11
    Re: Panel Snow and Ice

    Some industrious type will come up with a manufacturer approved de-icer which I'd buy to jump start the melting process.


    I mean they spray this stuff on airplanes?
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #12
    Re: Panel Snow and Ice

    Here is an article on Aircraft deicing fluid used at airports.

    Not cheap ($5-$7 per gallon) and usually is ethylene glycol or propylene glycol... EG tastes sweet and is very poisonous to mammals ("...can be fatal to humans even in small quantities..."). PG may have other environmental effects. And their are other chemicals in the mix too (non-corrosive to aluminum).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #13
    Re: Panel Snow and Ice

    I bet you would pay more for a treatment than the power is worth.

    Tony
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #14
    Re: Panel Snow and Ice

    rock salt ? Apply with the varmit shotgun for 2 story installs ?
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • Mangas
    Mangas Solar Expert Posts: 547 ✭✭✭✭
    #15
    Re: Panel Snow and Ice

    Rock Salt. And, I was sqeemish using a scraper!

    Bill's comment rules out aircraft de-icer's. Agree, not very benign and not a solution for our environment.

    I think I'll call the panel manufacturer and see if diluted windshield washer fluid would fly with them.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #16
    Re: Panel Snow and Ice

    Rock salt 2x a year can't be much worse than coastal ocean spray/fog 365. It's not a solvent, won't melt plastic, and organic. Won't help your foundation plants much though.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #17
    Re: Panel Snow and Ice

    anybody that is in the colder climates knows that salt may melt some snow and ice to about 17 degrees f, but even if it works it will leave quite a bit of residue and it's destructive power on metals will far exceed those of seaside locations in quick time. i know i've heard stories of how cars are with rust in seaside locations, but you haven't seen anything unless you live in an area that experiences lots of snow that gets salted heavily.
    now salt for many is a no go due to panel inclination too. salt is a bad idea no matter what way you look at it.

    sidenote-
    it's funny that we're talking of this while i've been experiencing warm temps for this time of year. 50 last night, 60s during the day and now 44 degrees f at about 2+ in the morning. my big concern right now is the nasty winds as i have been seeing consistent winds of 28-32mph and a reported gust of 92mph about 8pm about 3 miles away from me the day before. (no official word as of yet) my pvs' home made wall mounts are holding and i wonder if those 100ft+ trees in back of my property will stay put or come down onto the homes here? only 2 of those monsters are on my property with many more behind and off to the sides. what's worse is i live on a hillside so these trees are elevated above the homes and growing on a semi steep incline. it's not if, but when and these winds worry me. i know, cut 'em down. even if i had the money i have many higher priority items that need addressed first that i don't see happening anytime too soon.:cry:
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