Heat tape on the back of the panel to melt snow?

[dave]

I would just buy a roof rake - the shaft on it is 20 feet long and if you need longer then buy two. The plastic scoop on the front will not damage the solar panels and they are easy to push to the top of the array. As stated - once the snow is cleared off a bit of the panel it will evaporate quite quickly = Yes I wish it would just slide off of a 50 plus degree tilt at -20 C. I have thought of a black curtain on the front side to insolate and heat the snow but figure this may be to complicated so will look into this before I reach 85

[heartlander66]

Silicone-Rain-x

Polish when surface temp.= 65*+.

Hi everyone, I hope you guys don't mind me registering to ask some questions...

To give you a little background - I'm off the grid in north-central CO full time. I have a 2800 rated watt PV array running through a trace and a couple of outbacks, charging a 16 battery bank made up of Rolls 530 amp hour lead acid batteries. As you'd probably guess, the system runs great.

Only issue we have is in December when the temp drops to about -20 overnight and hovers around -5 during the day. When it's that cold, even 2" of snow on the solar panels isn't going anywhere, even in bright sunshine at 9600'.

Since I have a bit of a panel access issue, I've been kicking around various ideas about how to deal with the snow besides climbing up and brooming it off. One thing that came to mind was that since the panels are so thin in most places, I might be able to run heat tape along the back of the panels with the idea that I could even run the tape off my generator. I'm concerned that this approach will either generate too much heat and damage the panels, or not enough heat and will have no effect on the snow load.

Anyone here play around with this idea at all?

Thanks guys!

[jazzi be]

Sugar will work, though not as well. You're essentially trying to add a substance to the snow that will dissolve in water, thereby throwing off the balance between freezing and melting. ANYTHING that dissolves in water will help do this; salt works best because it's really cheap.

[Calgirl]

Snowed-in Panel Remedy

How about some foam insulated PVC/ABS with holes to blow hot air. Run PVC down to a convenient access point where you have a blower set up to blow hot air.

[ionized]

I was thinking of a similar Rube Goldberg solution, but with no hot air. Just string up some PVC to some points near the edges of the panels and connect them to a leaf blower. You only have to clear part of a panel to really accelerate the melting.

[osirisstevens]

Hello to everyone that needs snow melted from their solar panels during the winter months.
There is a company in Colorado that sells kits for snowmelt, [redacted]. They have a patented partner with an electro plastic that uses carbon nanoparticles to heat the solar panels.

It can be installed on any size solar panel and can adhere to a solar panel in 10 seconds. They are not a thin film heat tape/copper wire, heat tape of any kind, gas heated in any way, magnetically heated through four magnets that rub each other to create heat, heated hot water or liquid jell boiled in any way.

Their website is [redacted] and they do much more than just solar panel heating systems. They have micro-inverters that work with reactive power on demand 24 hours a day to give you a stronger power output from your solar array. They have racking systems, solar panels, carports, solar walkways, water creation from humidity, greenhouses, solar panels for greenhouses that grow food 40% faster than a regular greenhouse and use 5-70% less water for that growth, mobile greenhouses, and have three different types of DERM systems.

Mod Note: This is on the border between supplying information and advertising. I have made the URL information unclickable as a first step while we decide whether to allow the post or not.
ModNote2: The poster is a principal of the company involved. That makes it an attempt to get free advertising. Company link removed completely.

[inetdog]

Quite a few off grid folks in snow country just tilt their panels in the winter to a high enough angle that the snow does not build up and slides off every day.
Others use a snow rake from the ground.
It is interesting to look at the break even point between energy used to heat the panels versus the energy gained by uncovering them if the weather is bad. Certainly seems to need manual control.

[bcroe]

Hello to everyone that needs snow melted from their solar panels during the winter months.
There is a company in Colorado that sells kits for snowmelt, [redacted]. They have a patented partner with an electro plastic that uses carbon nanoparticles to heat the solar panels.

It can be installed on any size solar panel and can adhere to a solar panel in 10 seconds. They are not a thin film heat tape/copper wire, heat tape of any kind, gas heated in any way, magnetically heated through four magnets that rub each other to create heat, heated hot water or liquid jell boiled in any way.

You might start by telling us how much energy might be required to melt clear a generic (250W)
panel, and how to get and manage that much power. I already tried heating a panel with 3 times
its rating energy with no results. No need to attach anything, just fed it back, but I have no
source of power many times the array rating. Bruce Roe

[neweclipse]

This problem sure seems to have stumped the great minds here...

[Mike90250]

.... They have micro-inverters that work with reactive power on demand 24 hours a day to give you a stronger power output from your solar array.......

Ah, the moonlight panels 24/7 power scam

At one time, the midnight classic controller, had a snow melt feature, but again, backfeeding the panels to melt snow, took a lot of power

[inetdog]

.... They have micro-inverters that work with reactive power on demand 24 hours a day to give you a stronger power output from your solar array.......

The "work with reactive power" part does not sound like moonlight to me. Technically, in electrician speak, reactive power is that energy flow which cycles into and out of a reactive (inductive or capacitive) circuit component every half cycle of your 50 or 60Hz source, with a net energy flow of zero. Being able to generate a reactive power flow when needed can lighten the load on a utilities infrastructure, but still requires some sort of voltage and current source, even though little net energy is taken from it.
The other potential meaning of reactive power is power stored in an inductor (unlikely) or a supercapacitor (currently impractical and inefficient).
In no case could it be considered to "give you a stronger power output from your solar array", although when running a motor load, having an inverter that can source the associated reactive power locally can reduce distribution losses or triggering an overcurrent shutdown of the inverter.

[osirisstevens]

The PanelWarmer system takes 32watts a foot to melt the snow and can be turned off when not in use.

[bcroe]

I put 150W per foot into a panel without melting any snow. Bruce Roe

[inetdog]

I put 150W per foot into a panel without melting any snow. Bruce Roe

A problem in making these comparisons is that it is fairly easy to measure the heat needed to melt a particular amount of ice or snow when the ambient temperature around the panel is very close to freezing. At any significantly colder temperature some input heat to the panel will be lost to the environment (particularly at the back of the panel) without having any effect on the snow on the front of the panel. Without specifying the ambient temperature, wind conditions, and maybe even the design of the panel, the number of watts per square foot needed to melt snow is a meaningless number.
In addition, there is a possibility that the PanelWarmer system gets better performance by insulating the back of the panel to some extent when operating. But this would be counterproductive during the summer when you want to reject heat as fast as possible from the rear of the panel to minimize reduced power output as the panel temperature increases.

[bcroe]

I think we have established that this is not a trivial problem. 32W per sq foot is as much power as the
panel max output, just managing that on an array of size (or over paneled) is a problem about as big
as building the original system. I await a working demonstration. Bruce Roe