Entrepreneur Needed for Winter Solar Power Fix
“…in regions where homeowners have long rolled their eyes at shoveling driveways, add another cold-weather chore: cleaning off the solar panels. “At least I can get to them with a long pole and a squeegee,” said Alan Stankevitz, a homeowner in southeast Minnesota.” As he patiently squeegees off his stationary solar panels, day, after day, after day, throughout the long arduous winter in Minnesota…
Do you just accept this story as further proof that “it isn’t easy being green”? Do you see no alternative for this poor man but to just go out there and work this backbreaking labor for green energy? Do I hear you snort derisively?
Or… are you able to think creatively? Come on; give me your ideas for solving this. How hard would it be to plan for this kind of weather condition? Couldn’t cold weather solar providers offer a solution to this problem? I can see two very easy possible fixes right away. What solutions can you think of?
Caveat. Renewable solutions do not utilize fossil power. Let me know your ideas in the comments. Maybe you will start the little startup that makes millions off that solution… and we at Cleantechnica can write about your idea in a few years.
This blog brings you news of renewable solutions invented by others daily. Today , its your turn to sharpen your thinking-out-of-the-box skills.
The market for this snowy climate solar solution should be good, because:
“On the other hand, the panels can get extra power from sunlight reflected off nearby snow. And like other electronic gear, solar panels work better when cold.
Mr. Stankevitz said that on some rare winter days, when the Minnesota sky is clear, the weather is freezing and the sun is shining brightly, his panels can briefly churn out more electricity than they were designed to produce, more than on the balmiest days of summer.”
Image from Day Creek Journal
Story from the New York Times
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January 8th, 2009 at 7:51 pm
A much larger problem is keeping heavy snow and ice dams off roofs. The only solution that I know of is heat. That’s hardly efficient. However unlike roofs, solar panels don’t need to be fixed. Simply tilt them. Nice and easy with a lever and fulcrum.
January 8th, 2009 at 8:10 pm
Yeah – the fixed panels jumped out at me too!
January 8th, 2009 at 8:26 pm
Good post!
I think that a combination of temperature sensors and heat, along with back-and-forth tilting would be a good first step! Software would be the essential component to tie all of the technologies together
January 8th, 2009 at 8:41 pm
Well… Not that complex an issue really. If the solar panels are on a roof I would route the vents through the space between a double layer of glass over the panels. The heat would insure the snow would just melt off. If the panels are not roof mounted simply place the same sort of heating strips that are found in the rear view window of cars (well, at least around here in Scandinavia) which simply heats the window a bit. It should be able to run without being a big draw on the system. Other options of course are panels that just flip out when the sun is out and fold over when the sun is down or the sky is clouded over. Make them flip in such a way that the weight of the snow on them helps out and balance them so that it requires minimum effort to flip them back.
Or put shutters on them.
The possibilities are really endless.
January 8th, 2009 at 9:09 pm
So why not just do what car manufacturers did with windshield wipers? Attach a wiper blade/squeege to the top and sensor on the panel and when a certain amount of snow falls on it, the wiper automatically pushes off the snow. You could just use the energy from the panel itself to power the sensor and wiper, so no external energy is needed. Seems easy enough (but then again I’m no engineer….)
January 8th, 2009 at 9:14 pm
I am thinking a set of Chromed Alum. mini blind system with at least 6 inches of clearance between the blinds and the face of the Solar Panels would work. With the clearance it would allow for heavier snow at times and then just open the blinds either manualy or via solar powered energy source each morning. The reflective glare of the louvers will allow the little amount of snow left on them to melt off due to the reflective facing of the louvers. Any snow on them will fall to the ground when they are opened thus the need for the 6 inch clearance, or more of you want. Just a thought.
January 8th, 2009 at 9:27 pm
What great ideas.
“If the solar panels are on a roof I would route the vents through the space between a double layer of glass over the panels. The heat would insure the snow would just melt off.”
You mean the heat being expelled from the home,right?
“heating strips that are found in the rear view window of cars which simply heats the window a bit”
That’s another great idea. I wonder – could the solar power for the day keep those little window heat strips warm overnight?
“why not just do what car manufacturers did with windshield wipers? Attach a wiper blade/squeege to the top and sensor on the panel and when a certain amount of snow falls on it, the wiper automatically pushes off the snow.” – this sounds like it could work too.
January 8th, 2009 at 10:06 pm
Use round PV and have them slowly rotate when it’s snowing. Best of all, since snow is white more sunlight will be bounced right into the PV tubes. Round PV should already be on a white surface in the first place though.
January 8th, 2009 at 11:08 pm
Sounds to me like too many people have not lived in MN (I live in MN.) Its NOT a simple problem to solve. We frequently have freeze-on-contact rain and freeze/melt cycles which can make even a simple hinge lock up or crack. Wipers on our cars are glued down routinely and require work to free up.
Phase changing water from solid to liquid takes HUGE amounts of energy; its laughable to think of melting snow off solar panels.
Rotating panels to dump snow is a nice idea and works much of the time; except for ICE formation. There is currently no easy solution for all situations (easiest being squeegee + warm water for deicing.)
I’ve thought if I ever wanted to spend that kind of money, I would devise a clever roll up tarp that would cover it up and pull off the snow on the tarp as it rolled in. This wouldn’t solve everything but could automate most the situations. That ‘tarp’ might have to be metal…
January 8th, 2009 at 11:27 pm
I have thought about this problem as a pre-req for me doing solar in MN. Best I could come up with is in my previous post.
More detail:
At the bottom of the panels is a pipe that has a motor attached to it and it rolls in a tarp or metal sheeting. The end of the sheet would have a board attached at 90 degrees (facing up) to help the tarp pull the snow down when it rolls up the tarp. The trick in this involves cheaply keeping the protective tarp from rubbing the solar panels when it has snow on it. Rails are not ideal due to complexity/cost; same with a garage door system, which would obviously not roll up nicely but if you had the space you could adapt a garage door and components to avoid any fabrication.
I’ve been leaning towards tensioned cables to lower material costs and less issues with ice jamming that rails cause.
The choice of covering design somewhat determines how you rig up the mechanism to pull it back up again. But not so difficult that it needs consideration at this point.
Benefits:
fully automated
low power use to slide any amount of snow/ice off
low power to protect it
hale protection
Downside:
You have to switch it on or have a sensor trigger it.
MN weather changes frequently; can’t just use internet weather info to trigger it; can’t use low light/output either.
Material costs to make it able to handle X amount of snow load without touching the panels– supporting framework as well… (which is why I’m looking at tensioned cables and with less width per unit.)
January 9th, 2009 at 12:04 am
Living in ND, and wanting to get solar panels, I’ve thought about this a lot. The easiest solution I can think of is to keep the basic support structure, like the picture shows, but also enclose it. It will be a small space, so it won’t be hard to heat. Keeping it enclosed will allow you to force the heat up to the panels. The biggest decision is what to use to generate the heat.
If the panels are mounted on your roof, it would be more difficult, as most attics are insulated and will restrict the amount of heat needed to keep the panels clear.
Tarps are also awkward because you’ll need to be aware of when to cover up the panels, and then uncover them again.
My bigger worry than snow cover though, is how to protect them from the occasional hail storm?
January 9th, 2009 at 1:01 am
John, yeah: it helps to have that local engineering perspective. Moving electronic parts are not fun in Minnesota: my son’s VW window got frozen open in that pre-Christmas cold snap (just from sliding it down for parking thingies), and was just one of dozens of VWs getting that repair that week.
So, best local engineering perspective – low tech – tarps!
January 9th, 2009 at 5:31 am
I like John B’s idea for the most part. In terms of furling/unfurling the tarp, why not borrow an idea from an existing system? If you’ve ever seen a big commercial dirt truck on the highway (at least in a state with covered-load laws like WA), they usually have an automatic system for tarping over their loads. Here’s a link to a company that makes them:
http://www.harpstarps.com/electricwindupsystems.php
Also see the link partway down for the separately-sold “arm system/wand assembly.”
With a system like this, you would have the arms rotate from a point below the plane of the panels, and the system automatically maintains tension on the tarp. Since the arm ends follow an arc, the would keep the tarp off the panels while it was moving, and if you beefed up the hydraulics on the arm and got a sturdy enough tarp, you might even be able to get it to lift substantial snow loads off your panels.
Of course, there are still all the same sensing and automation issues, but at least this would solve a couple of your problems.
January 9th, 2009 at 6:29 am
Yes, routing the venting from the house between or under or over the solar panels should easily keep them snow free without any effort at all.
As for heat strips using massive amounts of energy to get ice off – yes. BUT… I would rather invest that massive amount of energy now and then and get more power in-between, then lose power altogether. And if the electrical system in my car can handle the load, then it sure wont break the bank for a good solar system.
But yeah, I believe the optimal solution is definitely connecting it to the ventilation system in the house. The windows of my house don’t freeze over because they are heated from within. Apply the same to the solar panels and voila – cost free heated solar panels. If you guys have enough contact-freezing rain that the situation is different there, then some mechanical solution is clearly the only option.
On a sidenote I feel it is a bit narrowminded to only think of a solution for MN – wherever that is. I personally live in Sweden and most years it dips as low as -30C (-20ishF) in the winter. So as non-local to you guys as I may be, I still know what a harsh winter is.
January 9th, 2009 at 3:53 pm
What if heating elements like those found in your car’s rear window were embedded in the panels’ glass?
http://tinyurl.com/7lmyef
January 9th, 2009 at 5:23 pm
Slightly off topic, but this is also a problem for wind turbines. Larger turbines will actually project lethal amounts of ice quite substantial distances!
We also had the same problem at our small wind turbine startup (www.wind-sail.com). In particular, our turbines were being deployed in Siberia and ice forming on the blade tips on quiet days could immobilize the turbine for all of winter.
On turbines, you probably don’t want a solution involving motors.
You probably cannot afford the energy required to heat this off.
For wind turbines, the best solution is probably materials that encourage water to form and move away, such as teflon-like coatings.
I don’t know if there are any transparent coatings for panels that would affect and/or slow down the formation of ice, but that’s an idea I haven’t yet seen posted here???
jeremy
January 9th, 2009 at 6:05 pm
Frank, sorry. MN = Sweden, etc, of course. (I had just returned to California from vacation there; the author is a little UScentric.)
Yes, your suggestion is the one I’d thought of too: before emitting waste heat from house roof – train it through tubes to heat the snow like radiant heat in flooring.
So many inventive ideas like Jeremy’s teflon-like coating – applied from a wind business. It is great to hear from people actually grappling with this problem.
January 9th, 2009 at 6:50 pm
Shawn’s idea is interesting:
“The easiest solution I can think of is to keep the basic support structure, like the picture shows, but also enclose it. It will be a small space, so it won’t be hard to heat. Keeping it enclosed will allow you to force the heat up to the panels. The biggest decision is what to use to generate the heat.”
If enclosed in a clear greenhouse to let the sunlight through – I think that in itself would warm the roof. (But then, the panels would not operate very efficiently in a greenhouse once it warms up. They need cold) So you would want the clear plastic only when you need it.
Unzip the greenhouse when it’s warm? Or build the panels in a separate clear section in the greenhouse roof that unzips open?
January 9th, 2009 at 8:09 pm
I got it! An invisible force -field like the death star, without Luke Skywalker taking it out. Or one of those Husqvarna solar powered lawnmowers parked in the corner of the panel array. It could act like a reverse zamboni whenever it sensed snow or ice. All that is needed is a rim around the around the array.
Seriously, a roll up rubber tarp should do the trick. Metal or plastic will just become too brittle in the cold weather to operate.
I’ll come up with something… just you wait.
January 9th, 2009 at 8:31 pm
Or just give up… One way ticket to Miami for the season.
January 10th, 2009 at 3:15 am
What about a larger motorized version of the squeegee. It could pass from side to side using a garage door opener motor and pulleys. You could activate it from inside or just put it on a timer. You could even use the motion sensor to detect the height of the snow. You would have to reprogram the brains of the opener though to work in reverse. When the sensors are blocked because of snow build up it would signal the squeegee to pass. I would also spray the panels with teflon and angle the squeegee like a snow plow. This As for the freezing rain on contact… there is not much on can do. To heat it off is just wasting the generated power. Maybe micro vibrations, but then again wasted energy. The best is to get it off as soon as possible. You may need to incorporate an H2O sensor.
Or you could try a low tech idea:
Since your panels are not attached to the roof you can change the angle of the panels during the winter (modify the structure of course). I know this will decreases the overall efficiency but so does 6” of snow. Check out this photo of a barn with three different roof pitches. The center section (probably a 12:5) has no snow but the other two less steep do.
http://www.fotosearch.com/sc/CSP013/0136427/
January 10th, 2009 at 6:30 am
You may want to look into hydrophobic coatings. They are used on satellite dishes to keep the snow and ice from sticking.
January 10th, 2009 at 4:08 pm
Being from Texas, I’ll never deal with that problem. But the problem we have in Texas that the hot summer sun heating the solar cells with the module heats up too high causing loss of efficiency.
I’ve put a lot of thought into that problem and I think my idea can work for those in Minn also.
In Texas the panels get extremely hot which causes inefficiency like I stated earlier. My solution is to install 1/2 or 3/8 PVC tubes behind panel and have an anti-freeze solution pumped to a water heater (solar thermal hot water – direct from the panel).
Now seeing your problem, I think if the inlet to the HW tank have a tee so that in the Minn. winter the solution from the rear of the panel can be diverted to an area where just enough heat can be absorbed to melt snow like an attic space or something?
January 11th, 2009 at 4:44 am
To the heater people:
My car heater in the back window wouldn’t remove any decent amount of snow in a day; it only works on the thin ice build up. 220 WATTS to heat that car window and the phase change takes 3 times the energy to change the temp to melting point…
Taking electricity to generate heat is wasteful. Heat from non electric sources is less wasteful but more complex than car-style electric heaters.
You shouldn’t have waste heat coming from your house in the 1st place! Heating is a bigger energy user than electric power; so I won’t be adding to that problem.
You could use the car-style heater to remove ice build up on panels but for snowfall it would be too wasteful to melt it. Look up the costs and power usage for people using driveway snow melting systems. You get so little already for the cost on solar this far north- undermining it further doesn’t help the cost/benefit ratios… (here in MN, its overcast 2/3 of the year)
January 11th, 2009 at 6:25 pm
“You shouldn’t have waste heat coming from your house in the 1st place!” true, but, they do. And it can still be reused. It doesn’t have to vent to air.
So why not use it before you lose it. Funnel the house’s waste heat down in pipes under the driveway (to melt that snow) and over these yard panels to strategically warm the top surface up too to melt off the snow.
(You would need to be able to close it off as soon as its melted, because solar panels work more efficiently in the cold.)
January 11th, 2009 at 7:07 pm
The main thing about the waste heat from the house is that it doesn’t need to be HOT – it just needs to be warmer than freezing.
Or a new idea – how about a transparent covering that moves? Say a slowly rotating cover of some form of plastic, just rotating around the panels. On the underside have some form of natural heatsource or scraper or whatever you can imagine to defrost the plastic as it passes by – some of the frost will already be loosened by having to crack as it is pulled over the edge – aided by some form of toothed scraper perhaps?
If you build it efficiently enough, just let the thing run any time the temperature dips – as it is moving constantly it should be harder to freeze up and break. If not, then simply build it as frost resistant as possible – there are plenty of research on making machinery work in cold weather.
Add a bucket of sensors for starting it at the first hint of snow or rain, add some more to warn in case of breakage – and of course have it warn and stop immediately if it can not pull the load (i.e. something froze that shouldn’t have)
Even if this can not be done, the covering can be of a manual type that you rotate to the underside where you can more easily get at it with a manual scraper.
January 11th, 2009 at 9:54 pm
Hi,
I don’t know much about the weather in that part of the world, but i find simple is best, and the simplest thing i can think of is -
I assume he is getting snow in the winter, when the height of the sun at midday is quite low. I also assume there must be an angle, or steepness at which it’s just too steep to get much snow sticking. If the platform could be tilted in the snowy winter to a much steeper angle, he may get a better angle on the sun, and catch a lot less snow, thin enough for it to melt off, when the sun comes out. As the seasons change, alter the angle of the panels as fits. But nice panel, and that fella looks pretty efficient anyways.
January 11th, 2009 at 11:29 pm
I think when life hands you lemons…you make lemon aid.
Enclose the bottom section of that users solar array, seal it up time and hook up a bbq smoker. I say let the smoke/heat escape past the smoker and get into the enclosure. It helps if you can fill a lot of that dead space in so you are not heating as much space. Just let the smoke escape on the far end. If you must produce heat to rid the array of ice get more than just snow free panels…get some bbq brisket too.
You create a lot of heat during the day that can be reused if you think about it. Cooking, Drying clothes or even running a cleantechnica.com server.
January 12th, 2009 at 7:58 am
Start your own solar panel cleaning business, stimulate the local economy and employ your neighbors and family.
January 14th, 2009 at 7:18 pm
Knowing nothing about solar panels, I am wondering if it could be installed to rotate toward the ground. It doesn’t snow every day in MN and most of the time we have some fair warning. A system that would allow you to rotate the panel as needed, so it is angled toward the ground…almost upside down. Maybe the reflection from the snow would still allow the panels to function? Otherwise, I don’t think shoveling the panels is a huge deal. It’s part of our lifestyle and some of us actually enjoy it. Melting the ice with little strips of heat might work in November or March…but keep in mind, it is 20 degrees BELOW ZERO in parts on MN today. Of course, it can’t snow when it is that cold.
January 16th, 2009 at 5:57 pm
Why not make the glass covering the panels similar to the rear windshield of car…press a button and the defroster kicks on and melts the snow
January 20th, 2009 at 1:54 am
I think some kind of tarp system is probably best. Some kind of contraption that lets him tarp over the cells at night, then pull it off in the morning.
Or, alternatively, pay neighbor kids to do it. 5 bucks a day…it would be easiest, though maybe more expensive in the long run. But it keeps jobs in the US!
January 27th, 2009 at 5:12 pm
[...] all, if folks in Antarctica and Minnesota can find ways to use solar, why not [...]
February 2nd, 2009 at 3:55 pm
Good question, since the ideal PV location on the upper roof of our house is virtually inaccessible without dual ladders, and worse, the slope is shallow. In Illinois, the big snows are not that frequent, but the heavy stuff can hang around for half the winter.
Like earlier commenters who observe that steep inclines shed their snow relatively quickly, I’ve been trying to imagine how mechanical advantage could be used in anticipation of heavy snow to just crank or jack them up temporarily to a steeper angle. Hinge them at the lower edge. Making sure they remain firmly anchored would be important due to the danger of high winds. Maybe it works something like those old, long, store front awning cranks. I would be willing to pay extra!
February 4th, 2009 at 3:21 am
you guys are overthinking this one. go to your local hardware and ask for heat tape. the kind some of you have in your gutters and up your roof valleys. depending on where the panels are located will depend how hard it will be to run power to it. the heat tape will not hurt the panel nor will it block any sun from charging it either. I would buy a thermostat so the tape would turn itself on when the temp drops down. as far as getting the heat tape to stick on the panel that should’nt be to tough i would use a gutter caulk to hold it in place,
‘geocell ” clear. the caulk will expand and contract with the weather conditions, and not run when warm. But only put the caulk on the aluminum edges not on the panel. clear will not be visible, and you should be able to get the caulk at any home improvement distribution center or store where professional gutter installers go, i have never seen this sealant at a hardware. do not use silicone or any other cheap caulk it will only peal of over time geocell will not peal if aplied to metal , you may need to use the roof fasteners that come with the heat tape to help hold it on the panel while caulk settles and for pole mounts get creative buy a spool of wire and loop the wires together in the back of the panel . hope it works well I did this for my buddy at his cabin in michigan. it works!