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Title: Building opportunities for photovoltaics in the U.S. Final report [PV BONUS]

Technical Report ·
DOI:https://doi.org/10.2172/763049· OSTI ID:763049

The objective of the North Carolina's PV Bonus Team was to develop and demonstrate a commercially viable, building-integrated, photovoltaic system that, in addition to providing electricity, would capture and effectively utilize the thermal energy produced by the photovoltaic array. This project objective was successfully achieved by designing, testing, constructing, and monitoring two roof integrated photovoltaic systems--one on a Applebee's Restaurant in Salisbury, North Carolina and the second on a Central Carolina Bank in Bessemer City, North Carolina. The goal of Innovative Design is to now use these successful demonstrations to facilitate entry of building integrated, pv/thermal systems into the marketplace. The strategy was to develop the two systems that could be utilized in future applications. Both systems were designed and then constructed at the North Carolina Solar Center at North Carolina State University. After extensive testing at the North Carolina Solar Center, the systems were moved to the actual construction sites and implemented. The Applebee's Restaurant system was designed to substitute for the roof assembly of a low sloping, south-facing sunspace roof that typically incorporated clay tile. After monitoring the installed system for one year it was determined that the 1.2 kilowatt (peak) system produces an average peak reduction of 1 kilowatt (rated peak is 1.7 kiloWatts), saves 1,529 kilowatt-hours of electricity, and offsets 11,776 kilowatt-hours of thermal energy savings used to pre-heat water. A DC fan connected directly to eight of the thirty-two amorphous modules moves air through air passages mounted on the backside of the modules and into a closed loop duct system to a heat exchanger. This heat exchanger is, in turn, connected to a pre-heat hot water tank that is used to heat the water for the restaurant. The Central Carolina Bank system was designed to substitute for the roof assembly of the drive-in window area of the bank. The design featured a triangulated truss that incorporated ten crystalline photovoltaic modules on one side of the truss and a reflective panel on the opposite side. The system used a utility interactive, programmable inverter and a 18.9 kilowatt-hour battery bank. The system is designed so that a DC fan, connected to one of the modules, forces ambient air across the back side of the modules. In the summer this heat is vented to the outside but in the winter this heated, fresh air is introduced into the building as ventilation air. Like the Applebee's system, the design allowed the entire roof assembly to be constructed off-site, tested, and then shipped to the site in pie-assembled, large components. During the first full year of operation, the 2.2 kilowatt (rated peak is 2.7 kilowatts) system contributed to an average peak reduction of .9 kilowatts. The system, as designed, saves 2,576 kilowatt-hours of electricity and offsets 3,473 kilowatt hours (of a potential thermal benefit of 10,172 collected kWhs) of thermal energy savings that is used as fresh air make-up in the colder months. This report is a summary of their conclusions.

Research Organization:
Innovative Design, Inc., Raleigh, NC (US)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EE) (US)
DOE Contract Number:
FC36-95GO10013
OSTI ID:
763049
Report Number(s):
DOE/GO/10013; TRN: US200308%%237
Resource Relation:
Other Information: PBD: 8 Sep 1999
Country of Publication:
United States
Language:
English