Incorporating solar electric devices into all parts of the building, instead of placing solar panels on the roof, is known as building integrated photovoltaics (BIPV), a concept that inspires many designers. By incorporating the function of solar panels into other building materials, the cost of PV will drop, in large part because the elaborate mounting systems sometimes used to meet structural and wind loading requirements are not needed. If solar energy is produced by windows, for example, it greatly simplifies the overall design and construction effort by eliminating dedicated mounting structures. BIPV also increases available surface area for solar collection.
Two photovoltaic technologies are commonly used for BIPV. Currently, monocrystalline solar cells are the most efficient and most costly, while thin-film cells are less expensive, but not quite as efficient. This means that monocrystalline cells are generally used where space is limited. Thin-film technology works well when there is more area available for BIPV systems, such as building facades, canopies and other structural elements.
Transforming building elements, such as roofs, walls, and even walkways, into electricity generators greatly increases the total potential energy output and can create a more even production throughout the day. Here are a few examples of how it can work.
Perhaps the easiest way to integrate a solar array into building architecture is to use a shingle that also generates electricity. Solar shingles cover the roof and generate electricity. While homeowners who buy solar electric systems generally love to see their investment, the neighbors may be less pleased. This approach makes the most sense for new construction, where a new roof is needed anyway. It also makes good sense when an existing roof needs to be replaced. Solar shingles may cost about 30% more than a typical solar electric installation. While the solar shingles lay flat on the roof structure, they are not entirely invisible due to a slight difference in color and reflectivity.
Another BIPV system, solar glazing, replaces windows and skylights. Although there is some reduction in transparency, the current generation of photovoltaic glazing doesn’t have visible wires. This approach has been used in several large commercial structures around the world. While the cost of solar glazing is currently higher than traditional solar modules, prices promise to fall with an increase in the number of projects that uses this exciting new solar technology.
A solar canopy or porch can cover an outdoor living space or entrance. Exterior shades, which are becoming more common to reduce solar gain in commercial buildings and homes, can provide electricity as well as shade. Electric vehicle charging shelters offer a unique opportunity to combine electricity generation and use. Here again, a single structural element has a dual function.
A solar faćade may be the ultimate application of BIPV. In this approach, the entire outer surface of the building produces energy. Several companies now make PV panels specifically for curtain wall and rainscreen applications.