In the pictures at the left and below, there are both types of Solar Energy Collector Panels on the roof of these typical single-family homes becoming increasingly common in the Madison area:  The upper (thermal) ones consist of evacuated glass tubes over a black heat-absorbing background, through which a liquid circulates into a storage unit inside the house. From there the heat or thermal energy absorbed is exchanged with domestic water supplies for direct use at the taps or for pumping through under-floor tubing to provide radiant space heating throughout the home.
The lower set of panels are photovoltaic (PV) which contain semiconductor electronic components which convert light from the sun into electricity, which is then available to use within the house, or to sell at a small profit back to the local power company for distribution via their grid to other electric customers still relying on more dated technology. |