Lean against a building's wall on a hot summer day and you can feel the sun's reflective heat. To better tap this under-used energy resource, builders and renewable energy experts are integrating electricity-producing photovoltaic cells into the exterior building envelope. Increasingly, PV modules are being considered as replacements for conventional facades, roof tiles, asphalt shingles or even shading devices.
Based on guidance received from leading manufacturers of PV cells, NIST has launched a multiyear research program to provide needed performance data on this innovative technology. The project involves a mobile tracking PV test facility, a meteorological station and a building-integrated PV testbed. The mobile facility records the effects of the angle, temperature and solar spectrum on the electrical performance of various PV panels. The meteorological station measures solar radiation, wind and temperature conditions during the performance monitoring of building-integrated PV panels. The testbed conducts side-by-side comparisons of four different types of PV panels�crystalline, polycrystalline, silicon film and amorphous silicon. Each PV technology is represented in the testbed by two panels: one without any thermal insulation behind it (representative of window and skylight applications) and one insulated to simulate opaque wall applications. The energy produced by each of these eight panels and the coincident meteorological conditions are recorded every five minutes for a year.
NIST researchers are using the data to improve computer simulation tools that predict the performance of building-integrated PVs for various geographic locations and building orientations. The payoff for success could be considerable, since residential and commercial buildings utilize more than 40 percent of the electricity consumed in the United States.
For technical information, contact A. Hunter Fanney, (301) 975-5864, [email protected].