A well rounded solar array
Barcelona architect André Brössel did not like flat panels, so he came up with solar generators that open up new possibilities in building-integrated photovoltaics and power plant design.
From the roof of André Broessel’s Barcelona office a good marksman could shoot a bottle off of the roof of Gaudi’s Casa Milà. Looking at that six-storey structure, it seems Gaudi was incapable of drawing a straight line or flat surface. Perhaps that is why Broessel cannot countenance a flat solar panel.
Broessel suggested to his team that they come up with a way to combine innovative design with photovoltaic power generation. The result was a patented system consisting of a glass sphere which acts as a lens to collect sunlight and bundle it onto a narrow strip of semiconductor. “A key factor in the efficiency of photovoltaic systems is a 90 degree angle of incidence to the semiconductor. This limits the potential of roof systems because the cost of tracking technology is immense. In addition, there are loading problems due to wind and snow.”
Always at a right angle to the sun
Broessel’s team analyzed different ways of keeping a semiconductor or thermal absorber at a constant right angle to the sun. A sphere solves this geometrical problem because it is an optical tracker that works without a module mounting or drive. In addition, a sphere concentrates sunlight to produce efficient solar power or heat. The simplest optical system offered by Rawlemon promises a 30 to 40 percent increase in efficiency when mounted vertically.
Single axis tracker
To bundle solar energy even more, the Spanish designers developed a single axis tracker for which wind and snow loads are negligible. The system needs 18 percent fewer solar cells than traditional systems using crystalline solar modules. In addition, the spheres have 57 percent more aperture area than flat modules. The spheres’ flexible design can be freely configured.