DUBLIN, Va. — The largest solar thermal system in the Commonwealth of Virginia has been installed at the New River Valley Regional Jail (NRVRJ), which serves the counties of Bland, Carroll, Floyd, Giles, Grayson, Pulaski, Wythe, and the City of Radford.
“The 138 collector solar thermal system at the New River Valley Regional Jail is the largest solar thermal project in Virginia, and one of the largest renewable energy of any type in the Commonwealth,” said Jason. A. Epstein, executive vice president, Baker Renewable Energy.
Baker Renewable Energy installed the ground mount system, which consists of 138 collectors, or the equivalence of 272 kW of photovoltaic energy. The structure will offset approximately 30 percent of the jail’s natural gas usage, and provide 2.5 million gallons of hot water per year to the facility.
The project consists of a 3,000-gallon underground water storage tank connected to more than 1,500 linear feet of underground steel pipe infrastructure, which runs back to the jail. As part of the initiative, Baker also installed a detailed weather station nearby to monitor system efficiency versus weather fluctuations.
“The system generates heat energy that it stores in a 3,000 gallon underground storage tank. As the facility demands hot water, cold water from the street passes through a heat-exchanger pulling heat energy from the storage tank,” explained Epstein.
The solar heating data collection system and weather data system can be used together for system performance analysis and for the preparation of graphics, which can be used for both technical training and for general educational use in energy conservation and sustainability awareness.
NRVRJ is a 296,000-square-foot facility, which has a rated capacity of 1,183 inmates. Baker Renewable Energy worked in conjunction with Virginia-based Thompson & Litton, an engineering, architectural, surveying and construction administration firm, to design a custom solution for facility.
“We had just completed a major renovation and expansion of the original regional jail facility and became aware of a potential funding opportunity through the Virginia Department of Mines, Minerals and Energy (DMME) and U.S. Department of Energy (DOE) for renewable energy projects,” said Bill King, P.E., vice president, Thompson & Litton.
The $856,000 project was funded with a $410,880 grant from DMME/DOE, with the balance of funding coming from the NRVRJ Authority. In the end, the project was completed for approximately $800,000, which also included a 15 percent increase in the size of the project as originally bid, said King.
Gerald McPeak, the superintendent of the New River Valley Regional Jail, noted that the local governments are being forced to assume more and more financial burdens in today’s tough economy.
“Our population and therefore our demand for hot water is growing much more quickly than we expected,” said McPeak. Rising fuel costs made the prospect of a renewable energy source a likely choice to reduce operating expenses.”
“We looked to Thompson & Litton and Baker Renewable Energy to design and build a solution that would allow our facility to become more energy and cost efficient. The Thompson & Litton and Baker teams faced many challenges while working at our facility. Fluctuating weather conditions, extensive underground infrastructure and working in a high security environment made the project complex in a number of ways.”
Of the 138 collectors, which comprise the solar system, each is 4-feet by 8-feet in size, and provide a new collector surface area of 4,140 square feet. The collectors are flat plate using copper tubes bonded to a coated aluminum plate. The tubes are arranged in a “harp” pattern and six collectors are piped in series for a total of 23 individual collector arrays.
Insulated copper tube is utilized for the piping on the collector arrays while insulated steel piping is used for the larger common piping. The piping is routed underground between the collector array, located on the ground and the jail building while the piping, on the jail building, is routed overhead outside on the building wall.
“Putting 138 collectors on one ground mounted system is a big deal,” said Epstein. “We've been at this for a long time now, and even some of our larger installations haven't topped 50 collectors on any single project. It's exciting to see the [New River Valley Regional Jail] authority taking a bold stance like this."