Thin-film photovoltaics with solar-thermal tech- nology create building- integrated PV-thermal, or BIPV-T: Pfister Energy, www.pfisterenergy.com
combination of thin-film PV with solar-ther- mal technology as part of the roof is called building-integrated PV-thermal, or BIPV-T. The two technologies, installed during new or retrofit roofing projects, work together to harvest the maximum amount of solar energy to generate power and heat water. The performance data from the demon-
ONGOING SERIES
This article is the second part in an ongoing series about the integrated metal roof retrofit as- sembly at Goodfellow Air Force Base, San Angelo, Texas. The first part in the series appeared in the September-October issue, page 30, and was an overview about the project and individual components that came together to create the unique demonstration project. The third part of the series will appear in the January-February 2013 issue and will focus on the cool metal roof- ing platform used in the retrofit assembly.
stration building being collected and au- thenticated by Oak Ridge, Tenn.-based Oak Ridge National Laboratory during a one-year period will be used to verify the predicted energy savings from the PV installation on the 11,900-square-foot roof. The PV system is projected to generate about 65,000 kilowatt hours of electricity and save the air force base approximately $5,200 annually on this building’s electric bill. Equally important to the base, the solar-power system brings it closer to meeting the federal mandate for the use of renewable-energy sources. The Goodfellow AFB roof PV system has been in place since June 2012 and is already producing enough electricity to offset 37 percent of the building’s usage based on 2011 consumption levels. More importantly, 2011 was one of the hottest summers and achieved the highest usage rates in recent years in the San Angelo region. Goodfel- low AFB has an electrical grid of its own
within the base, so any excess electricity not consumed by the demonstration project building will be fed into the base’s internal grid and used downstream by the next base facility. Bearing in mind that the goal is to
provide a minimum of 25 percent of energy needs away from the grid, this performance exceeds the stated DoD goal. As an added bonus, the American Electric Power Texas North City Smart Program, which provides government institutions with cash incen- tives ($150 per kW) for reduced peak electric demand from renovation or new construc- tion projects, gave Goodfellow AFB a one- time payment of $6,184 for this improve- ment. Ninety-six percent of this payment was credited to the PV system. The base demonstration project is
intended to verify the estimated kWh of electricity that can be generated for cooling/ heating/operation of a building. In addition, the reduction in grid-required electricity will result in a significant reduction in carbon- dioxide emissions attributed to the build- ing. The ESTCP project expects to generate data about energy and water reduction that can be used to model the performance of any building being retrofitted on any mili- tary base to meet its stated energy goals.