When pursuing the thermal snow melt possibilities, I contacted the Calorique company.
They make an interesting series of flat heaters, that are used for radiant heat, snow and ice melting,and some industrial heating.
I got the sample of the material today, and was pleasantly pleased by what I saw. The heater elements are dense carbon strips about 2" wide.
The 24.5" wide material has 3 copper bands, one on each edge, and one down the center.
The heaters can run on 240 VAC,by connecting the power at the two extremes, or 120VAC where the two extreme ends are connected to neutral, and the center to the 120V line.
The materials are sandwiched in a multi layer stack, with tough plastic between the layers. One side has an aluminum layer to act as a heat spreader, but one can see clearly where the heating elements are located when viewing the panel in IR.
I will install the heater on the top solar panel on my test rig, and give it a shot if we get more snow.
It looks like each 2" carbon strip within the heater can be cut off, and it becomes a 20 W 120/240VAC heater, so one could just unroll the length you want, cut it off, and make the AC connections.
The IR image on the left was after 2 minutes of being plugged in, and the one on the right was after ~ 30 minutes showing that the panel was at equilibration with the room ambient temperature and was no longer rising. Of course if adhered to the solar panel, the solar panel mass would determine the final temperature and rate of heating.
Very Cool product, (think lithium pack heater) They make variations for many applications, with more or less watt/ sq foot. Next thing is to find out how much it cost.
It will take 175 Linear feet to cover all the panels, and 12.5KW to power them all.
If my rope sweeper works, that will be the preferred solution