Keep snow off solar panels!
Comments
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Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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Re: Keep snow off solar panels!
Guess I will try rainx on a couple of my panels and see for myself what it does.
Solar Vic -
Re: Keep snow off solar panels!
try it on a sheet of glass placed over pvs. 1st without it and then quickly with it so that insolation and weather conditions are the same. the differences may be small so accuracy in voltage and current is needed into the same steady load. -
Re: Keep snow off solar panels!
I would like to add that if you mount the panels in landscape mode they should work better in areas that get snow. The idea is that if snow slides down the panel but still blocks the bottom cells it can still stop the entire panel from working(if the panel is in portrait mode). If the panel is on it's side(landscape), snow across the side will only take out one row of cells. This applies if the panel has blocking diodes. I am not sure if this is standard on every panel these days and I would like it if someone more knowledgeable would comment
My brother wants me to put panels on his cottage which gets lots of snow and someone is not there during the week in the winter. I am thinking of using panels in landscape on a raised rack to allow the snow somewhere to go, and Enphase microinverters -
Re: Keep snow off solar panels!
Grid tieing the cottage? Enphase inverters only work when connected to the grid.
Ralph -
Re: Keep snow off solar panels!Grid tieing the cottage? Enphase inverters only work when connected to the grid.
Ralph
Yes, there is a new program in Ontario that pays 80 cents a kw. I'm going to cover every roof I have and some of my family is going to get in on it as well -
Re: Keep snow off solar panels!
gee, i'll sell them my power at 80 cents/kwh and i'll have a profit of 60+ cents/kwh. -
Re: Keep snow off solar panels!
Neil,
Any subsidy is in the tariff price. You can re-claim 3% of the installed price from Provincial sales tax, perhaps 5% federal tax..if you're registered to collect and remit and a bit of accelerated depreciation, but that's it! No $50K system costing out net at $15K or anything like that. You put up your money (or the bank's in most cases) and get a 20 year contract at the 80.2 cents per KWH. That's the sweet part of the deal.
It's looking good here, lots of response to the program. 40% Ontario content is driving the first phase of development...you must have 40% content from Ontario, becoming 60% after this Dec 31st. It's ramming a green industry into Ontario, or that seems to be the plan.
I've modified my plans from just selling and remaining domestically off grid...to selling and net metering my domestic excess as well. That gives me cheap grid power to charge batteries when necessary (cheaper than diesel) and offsetting that cost by net metering. There will still be the monthly ''I'm on the grid"charge of about $25 plus taxes (yearly works out to more than my diesel charging costs).
Ralph -
Re: Keep snow off solar panels!
I know that this thread is old, but I just wanted to point out a phone call that I just got from a guy who installed solar panels this past summer. He called me wanting to know how to keep the snow ON his solar panels. The snow melted and slid off his roof creating a miniature avalanche and crushed his windshield as well as tore his gutter right off the side of his business. -
Re: Keep snow off solar panels!
with that much damage it's a wonder his building didn't get damaged. huge snow accumulations need removed regardless if one has pvs or not. -
Re: Keep snow off solar panels!
In addition to what icarus has said, I will say that many grid-tied systems are installed at the same angle as the roof. For these systems a shallower angle is often optimum since they are typically optimized for year-round production. Around here (VA), a 30 degree pitch is near optimimum for grid-tied applications while over 50 degrees is needed to optimize production in the wintertime for an off-grid application.Solar Guppy wrote: »Latitudes that have snow require the panels be at a steep pitch for proper operation ( Sun angle is very low in the horizon and require 45 to 60 degree pitch on the panels ). Panels self-shed the snow
It has been a while since you posted this, Robin! Do you have any updates to report?Robin Gudgel wrote: »I'm not suppose to talk about this yet, but suffice it to say there is a solution coming soon.
Robin Gudgel
MidNite Solar
That's my plan, also. My solar panels are on the roof, but they are easily accessible from the ground with a long roof rake. But my roof rake is all aluminum, including the head. It has foam rollers to protect the roof, but I'm worried about slipping and banging a panel with the edge of the rake. Can anyone recommend a good *plastic* roof rake head?poleikleng wrote: »I use a roof rake, aluminum pole with plastic scoop so it will not damage the solar panels.
That is exactly what happens on my installation. In my case, I was forced to move the panels up to the ridge of the roof due to a fake (cosmetic) dormer that is part of the roof.1) I had my panels pushed as close to the front edge of the roof (away from the ridge line) as possible. This way when the snow starts to melt (and it will start to melt from the black panels up against a warm roof) the snow doesn't get hung up on the roofing shingles.
I have since posted a thread about this topic.This has worked out almost TOO good. I worked from home today. The snow (about a foot's worth) has completely come off of my panels. One little blotch on a single panel near the top. The problem is the snow comes off in HUGE avalanches. If anyone is standing in the garden they will absolutely be knocked out by the force. It sounds like a train when it slides off the roof (and hits the hits the bay window kick-outs). This part I did not think through. I have twin 4yr old boys. So this is an ongoing/growing concern.
aside: this is our 3rd fairly large snowfall. After each, the snow has shed off the roof very very quickly. I'm kicking myself that I didn't setup a video camera. I will the next time.
You post makes me SO glad I installed my array myself! It was a LOT of work, but all during construction I was discussing with my helpers that "There is NO way any contractor would do THIS." There were many such issues!2) I had my panels strung such that (with the notable exception below) the top two rows are a single string. This way, as the snow slides down (but not totally off) this one full strings comes alive. And that worked today. After a HUGE slide, I went to the monitor page. I could see that one of my inverters was working at around 60% and the other was at zero. Just like I designed it - if I could reach my back, I'd pat it.
3) The 3x3 grid on the right (see the photo on my blog) is a separate string. This string is subject to diffuse shading in the winter. Again, this way, if this group of panels are experiencing shading, the other 3 strings are free to generate at full output.. assuming no snow. Shading is more of a problem for me than snow. I am trying to figure out just how much $$$ I am losing from the shading. I really really don't want to cut down or top the trees. Trees are good too you know.
So my strong recommendation is to take these issues into consideration when you plan your system. Think about the things that will diminish your output and take actions to mitigate them. The company that did my system did a very good job, but they did not think these issues through. If left to their own wits, they would have strung my panels up-and-down from left-to-right. This would have resulted in diminished output under anything but full/direct sunlight. My approach allows for graceful degradation under normal environmental conditions. Frankly, I'm a bit shocked that I don't see more vendors focusing more on graceful degradation - maybe I just didn't look hard enough. I take graceful degradation into account on large scale SW systems I design - so my brain is just wired that way.
Good luck. I don't normally follow this website. If you need to reach me, post to my afore mentioned blog and list this site. I will travel back to respond.
-ken
PS: I forgot to mention, I also had the panels biased as far to the north on the roof as possible. Pushing them as far from the shading as possible. I tend to forget that part because the vendor didn't do such a good job. They could have been another 1.5' to the north. I didn't pick up on it till way after the rack was installed.
BTW, if your system is grid-tied, then I think using microinverters gives the BEST overall production in the presence of shadows from snow or other since each panel produces as it clears. Of course this is not an option for an off-grid system (at least not yet...).
Please have a look at the existing thread I have started on this topic. No obvious answers, but there is some good discussion there.I know that this thread is old, but I just wanted to point out a phone call that I just got from a guy who installed solar panels this past summer. He called me wanting to know how to keep the snow ON his solar panels. The snow melted and slid off his roof creating a miniature avalanche and crushed his windshield as well as tore his gutter right off the side of his business. -
Re: Keep snow off solar panels!
I don't know if HD in the U.S. carries them, but I use this one from Garant to clear my panels.
I actually have two of them... I had one from before actually used to do a regular roof. When I installed the panels, I found I needed to buy a second (the pole sections anyway) to be able to reach all the way to the top of the 18-foot array on my garage roof when standing on the driveway (buying a second one and using just the poles was easier than trying to find the extension kit).
Turns out I actually use both heads now... the hold-down hardware between the columns of panels kept catching the blade, slowing me down and leaving a lot of snow. So, I bolted some brush sections sawn from four cheap Walmart auto snow brushes onto the bottom of the second blade and made essentially a lightweight broom. Now, I just use the original blade to do a quick job down the center of the panels, avoiding all the hardware, and then switch the head to the broom to do the remaining strips where the hardware sticks up. The bristles just slip right around the hardware and it gets them completely clear. For light dustings I just use the brush from the start and it only takes 5 minutes to do an 18 panel array (takes longer to get it out of the garage, assemble and re-stow than it does to clear).
I live in southern Ontario and we've had such cold highs (and relatively little full sun) that if I didn't clear them they'd never get warm enough to self-clear (the angle is only 23 degrees)... I'd have about 2 feet on them by now and it might not melt off until April! -
Re: Keep snow off solar panels!
We make off-grid solar powered aeration systems. The majority of our aeration systems are installed above snow belt areas in ponds and livestock tanks. We keep snow off our solar panels or else fish and livestock die.
Assuming you have the correct angle +40 degrees then you just need to keep a small opening through the snow to the PV glass at all times. Then when the sun comes up it will do the rest. Of course the larger area kept free of snow, the better.
We first ran across the EZdeicer roof ice dam nylon pantyhose in a "This Old House" article in 2001. You fill one leg of an old panty hose with with calcium chloride ice melt, which is windshield safe and non-corrosive to metal. Ice melt manufacturers say it won't pit it as long as you put it in the sock and do not put the flakes directly on the metal. We quickly learned to make our own refillable polyester ice melt socks and have used them ever since to keep the snow off our PV panels all winter long. -
Re: Keep snow off solar panels!
I'm very lucky here, living just North of 45, during Winter I can set my panels vertical, not kidding. Yes, there is a SLIGHT decrease in power directly from the sun, but it's more than made up for by the sun reflecting off the snow and bouncing up on the panels. As well, the total lack of hassle chasing after them to keep the snow off, and that total lack of snow is a huge advantage in power production week by week. I never have to bother even looking at them id I don't want to, they just sit there doing their thing, and within 5 minutes of the sun coming up over the Eastern horizon, power is pouring out of those panels. For me, it's the only way to go. Then come Spring, I tilt them back up again for the Summer. My highest power outputs are definitely during Winter. -
Re: Keep snow off solar panels!
Wayne,
That's what I do as well. I have several panels wall mounted, on hinges so I can adjust the angle as I wish over the course of the day/year. I leave on set vertical when ever we leave in the winter, so no matter how much snow, they always produce when the sun is out. The reflection off the snow is considerable.
T -
Re: Keep snow off solar panels!Wayne,
That's what I do as well. I have several panels wall mounted, on hinges so I can adjust the angle as I wish over the course of the day/year. I leave on set vertical when ever we leave in the winter, so no matter how much snow, they always produce when the sun is out. The reflection off the snow is considerable.
T
Mine are also hinged at the top on a South facing wall, and in Summer, I just lift out the bottom of the rack and lock it in the new position. Couldn't imagine anything simpler.
Actually I have a mechanism that uses a wench to push the bottom out to the Summer position, all from inside the solar shed. Right now of course they're locked in the vertical position for Winter. -
Re: Keep snow off solar panels!waynefromnscanada wrote: »I'm very lucky here, living just North of 45, during Winter I can set my panels vertical, not kidding. Yes, there is a SLIGHT decrease in power directly from the sun, but it's more than made up for by the sun reflecting off the snow and bouncing up on the panels. As well, the total lack of hassle chasing after them to keep the snow off, and that total lack of snow is a huge advantage in power production week by week. I never have to bother even looking at them id I don't want to, they just sit there doing their thing, and within 5 minutes of the sun coming up over the Eastern horizon, power is pouring out of those panels. For me, it's the only way to go. Then come Spring, I tilt them back up again for the Summer. My highest power outputs are definitely during Winter.
I like the idea of using the reflection of the snow. We have snow on the ground here for 6-7 months out of the year. Only makes sense to use it to your advantage. -
Re: Keep snow off solar panels!
Wayne,
I am not sure my wife would approve of my using a wench to prop the panels!
I use essentially the same system, using a prop on the bottom, adjustable so that I can control the angle.
Tony -
Re: Keep snow off solar panels!Wayne,
I am not sure my wife would approve of my using a wench to prop the panels!
Tony
Hahahahaha Guess I let the cat out of the bag with that one! Hahahahaha -
Re: Keep snow off solar panels!alex@aspenlog wrote: »I am researching starting a new company selling solar panels in Utah, and very quickly realized that there is nothing developed to keep snow off of the panels in winter. I have since started development of a simple device to do just that, but wanted to get some feedback before starting production. How big a problem is keeping snow off of the panels?
Having a device will be great for solar users in the north east
Do you have a prototype? My email is hitch.post97@gmail.com
I produce solar recharging stations for electric vehicles , golf carts etc.
BB -
Re: Keep snow off solar panels!
I saw a charge controller somewhere on the net - which of course I've never been able to find again - that had as one of the features listed on the spec sheet the ability to feed power from the battery to the PV module so as to heat the PV module and melt off the ice and/or snow.
I can't remember if it was a standalone, or as part of a kit that came with the PV modules. My dodgy old memory tilts toward "part of a kit".
As I recall (or don't as the case may be), it was an automated function and had something to do with a timer - as in "the sun should be up, but we're getting no output from the PV, so let's do the backfeed thing and heat em' up". Maybe involved temp too. -
Re: Keep snow off solar panels!
Wow! using battery power for electric heat to melt off the panels? I'll stick to my vertical winter positions. May loose a wee bit, but I'm sure it's more than made up by reflection from snow, and this winter we've ended up having the most snow in at least 20 years, and not once did any snow collect on the panels.
Me very happy
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Re: Keep snow off solar panels!
I'm certainly not a electronics tech, but doesn't the blocking diodes prevent that from being possible? -
Re: Keep snow off solar panels!
DWH you may want too check the Midnite Classic on its own bulletin board.
there is a thread there about snow melting
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West Chilcotin, BC, Canada -
Re: Keep snow off solar panels!I'm certainly not a electronics tech, but doesn't the blocking diodes prevent that from being possible?
Not all panels have blocking diodes in them, and if the charge controller has the ice melt feature, a relay or power FET would bypass it. (if there is any juice left in the batteries)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 , -
Re: Keep snow off solar panels!
Yes like Westbranch said, the thoughtful guys at Midnite are working to supply this with the Classics. Here, the panels are placed on the ground with no place for the snow to slide off. The power consumed is what I would call total melt. 1 KWH as I understand it under these conditions across a 3 hour cycle.
If there was space for the snow to slide off it would have been much more efficient. I've noticed on my system that the snow doesn't always slide off the panels if it is cold enough outside, when the snow is thick enough or the sun not quite strong enough to heat the panels. This could effect things badly if enough time passes with the panels stopped up.
I thought it a good idea if used in moderation at the right time. Heres the vid provided by boB: http://bob.gudgel.org/PVsnowMelt3.gif
I'm looking forward to this feature. Of course with grid tie only there would need to be a different device... -
Re: Keep snow off solar panels!
Hrmm. Perhaps I should have been clearer. Perhaps what I should have said was, "I saw this on the net some years ago."
Certainly a neat idea. Certainly not a -new- idea. -
Re: Keep snow off solar panels!
DWH, the automation portion you described may have been the downfall of the design. I can imagine a lot of cold cloudy days where a device like that would be tricked into thawing air. I see the need for this to be a manually activated task. Sensors fail.
Good news is the Classic will allow this task to be performed from near anywhere in the world with web access. -
Re: Keep snow off solar panels!DWH, the automation portion you described may have been the downfall of the design. I can imagine a lot of cold cloudy days where a device like that would be tricked into thawing air. I see the need for this to be a manually activated task. Sensors fail.
It's not terribly useful to theorize about the flaws in the design since, as I stated, I can't even remember if that was a part of the design.
All I can remember for sure is that a few years ago I saw a charge controller that claimed it could backfeed the panels to melt ice and snow.
I think...maybe it...might...possibly have had some sort of timer function. Thinking more about it after having slept on it a bit, I now seem to recall something about syncing time to some form of world clock or something so it would know when the sun was supposed to be up.
But who knows...I can't recall.
It didn't really sink in when I first saw it how unusual that particular feature was, and every now and then I get curious about the details. I have searched the net for that thing a few times (and I'm bloody good at searching the net) but have never found it again.
Thinking about it some more as I sip my morning coffee...it might have been a European unit. But again...who knows.
Also, there is no need to sell me on Midnite products. I already love what those guys do. -
Re: Keep snow off solar panels!
Well then, I'll call it new and continue to tip that hat to MN for supplying it to me. I sell nothing here.
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