The following are some notes and pictures from Jeff from the SimplySolar Yahoo group detailing some tests he did using strips of black tape to assist with snow melt on parabolic mirror solar collectors that otherwise have very little black at all.
January 13, 2011 - My panel has very little Black exposed, just the pipe. Eventually it will radiate enough heat to melt snow/ice, IF the sun can get through the stuff first. Even after brooming off the loose snow (mine is ground level) the ice build up Saturday evening completely blocked visibility. I was able to easily remove the glazing, which I did and took in the garage to thaw. However, when I replaced it I placed 3 strips of black electrical tape on the glazing supports. That little bit of black makes a world of difference. It clears ice/frost really quick now.
January 22, 2011 - Here's a couple of pix (series-cut-paste) I put together to show the black tape assisting with snow melt. These are a series of pictures that shows the progression of the melt. The parabolic collectors don't have much exposed 'black' to radiate heat for snow melt. I think the black tape helped & the pictures show it, especially on the supports without tape.
I had to brush off the 3-4" of snow prior to the pictures. It's unusual to receive a slow snow fall in Illinois. Generally it's blowing snow & it accumulates in drifts. In this case it wasn't windy & covered the entire panel.
I thought it was interesting the taped supports didn't have any snow/ice accumulation after I brushed off the snow.