Step Two: Energy and HVAC
The county installed a 60-kilowatt (kW) solar photovoltaic system for onsite energy production and a highly efficient 17-ton closed-loop geothermal HVAC system at the facility. Conservation through the geothermal system was a key component of the facility’s energy makeover to maximize the impact of the renewable energy.
The extremely efficient 40 SEER-rated geothermal system supplies 17.5 tons (210,000 Btus) of energy for heating and cooling. A series of 60 vertical well loops extending 90-feet deep into the ground recirculates water through buried small-diameter HDPE pipes. The geothermal system uses heat from the ground and underlying Floridian aquifer to provide a stable supply of 68 F water to the facility. In addition, for the past year, the geothermal system has been supplying hot water to the facility.
The PV system is designed to power approximately 40 percent of the building, or 40 percent of the original energy “footprint”. By installing geothermal, updating lighting, weatherstripping and educating occupants about wasteful behaviors, the center uses much less energy than it did previously. (Read a report about Zero-Net Energy Certified facilities.) Consequently, the solar-power system provides as much energy as the center needs.
A total of 253 south-facing solar modules were mounted atop a new structural-steel frame constructed on top of an existing parking lot. In addition to power generation, the structure provides a 60- by 100-foot shaded parking area that includes an electric-vehicle charging station. Each solar panel in the array is equipped with dedicated micro-inverter technology, allowing the panels to be independently monitored and respond individually to changing conditions. For example, passing clouds may cease electricity production from one area of panels while the panels in another area remain unaffected.
Combined, the new energy and HVAC systems were a strategic capital investment for a heavily used public facility. The systems not only bring about major reductions in operating costs, but are expected to last for the lifetime of the facility.
Onsite Education Programs
Leon County Extension reaches approximately 40,000 people annually through its various programs. The Sustainable Demonstration Center will help maintain the momentum created in energy- and water-conservation educational programming presently being carried out by staff of the Leon County Cooperative Extension and other offices.
Although the center’s geothermal system and rainwater cisterns are underground and leave little to visually observe, an interactive kiosk was designed to provide an overview of the Sustainable Demonstration Center, as well as show live energy-production and -consumption data.
Local governments seldom accomplish zero-net-energy buildings and they are even more rare within existing 50-year-old buildings. Many counties across the country are taking stock in a more sustainable future but Leon County is leading the way when it comes to “walking the talk”. “In Leon County we saw this opportunity as a win-win project,” says Leon County Administrator Vincent S. Long. “In county government, when you can save money, protect natural resources and make a community space even more appealing, you should act. This facility is a great learning opportunity for the community members who visit daily and for our peers throughout the region.”
The Leon County Sustainable Demonstration Center represents a mark of accomplishment not only to the community in which it was built, but also for the community it serves.
PHOTOS: Leon County
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More great modeling of the sustainable mindset. Conserving resources for the future.