Turnbull National Wildlife Refuge Maintenance Shop Energy Retrofit Team
Fish and Wildlife Service, Cheney, Washington
Point of Contact
An integrated design team guided the collaborative planning and design process for the 6,000 square-foot, high-performance, heavy equipment maintenance building renovation at Turnbull National Wildlife Refuge (NWR). Renovation methods specified are simple and transferable, and ongoing operations and maintenance are easy and inexpensive. The project implemented energy conservation measures and renewable energy sources while conserving water, managing materials sustainably, and maintaining indoor air quality. The design team ensured incorporation of these goals throughout the design and life cycle of the building, including deconstruction. Care was taken to ensure that the building complies with the Guiding Principles for Sustainable New Construction. Building features include a geothermal, ground source, heat pump; solar-thermal HVAC system, solar photovoltaic system, and WaterSense plumbing fixtures.
Northeastern Washington is a relatively windy and cold climate where temperatures routinely are below zero Fahrenheit during the winter. Consequently, reducing building heat loss was a key element of the renovation by implementing the following energy conservation measures:
- Eliminated or downsized unnecessary or oversized doors and windows.
- Replaced conventional R-3 coiling overhead doors with R-13 insulated sectional overhead doors.
- Replaced R-3 metal-frame double-pane windows with R-4 triple-pane low-e vinyl-framed windows.
- Replaced large roof skylights (single-sheet translucent fiberglass panels) with energy-efficient solar tubes that passively spotlight key work areas.
- Replaced fiberglass batt insulation in walls and ceilings with spray-applied expansive-foam insulation that seals and insulates the metal-frame, metal-skin building.
- Installed Water Sense low-water-use type fixtures.
- Retrofitted existing T-12 lights and magnetic ballasts with high-efficiency T-5 fluorescent lights and electronic ballasts, LED lights, and LED Exit lights, all controlled by motion sensors and photo-cells.
- Added ceiling fans to high bay areas to reduce heat loss though the roof.
- Replaced all appliances in the break room with ENERGY STAR® appliances. Taking advantage of renewable energy sources via a geothermal (ground source) heat pump, a solar-thermal HVAC system, and solar PV electricity was paramount. In addition, installation of these renewable energy technologies reduced the 1,500 gallons of propane formerly used for building and domestic water heat. Now propane is only used to operate the standby power generator during power outages. Total energy savings is 88.8 MMBTUs (equivalent to 26 MWH), or, assuming a 20-year period, an estimated lifecycle energy savings of 1,776 MMBTUs. The total fuel cost saved in 2010 is credited and reported as energy savings.
- Geothermal Heat Pump: The primary heat source for the building is a 15-ton closed-loop geothermal (ground source) heat pump HVAC system serving six small office unit heaters and six larger indoor direct-expansion force-air heat pump units. Methanol-water brine circulates though 0.75-inch diameter HDPE piping spaced 12 inch apart and buried 5 feet below ground, which takes up 0.5 acres. The manufacturer s rated Coefficient of Performance (COP) is 3.51.
- Solar Thermal Collector (pictured right): During daylight hours even through clouds, a 560-square foot, closed-loop, fixed-tilt, flat-plate solar-thermal collector provides supplemental heat to the HVAC system, provides 100% of the domestic hot water demand, and preheats the ground within the geofield.
- Solar PV System: The net-metered, roof-mounted, fixed-tilt 12 kW solar PV system provides direct renewable electricity to the building, which also provides power to the geothermal heat pump. The 11.2 MWH of direct renewable solar PV electricity, plus an estimated 64 MWH of indirect renewable energy from the solar-thermal array and geothermal heat pumps combined generate approximately 75.2 MWH of renewable energy annually, or, assuming a 20-year period, an estimated lifecycle renewable energy production of 1,504 MWH.
- Domestic water conservation is important, too. All plumbing fixtures in sinks, shower heads, lavatories, urinals, water closets, and toilets were replaced by WaterSense low-water-use technologies. Domestic water to the building is now metered. A total water savings of 1,100 gallons in 2010 was realized (1.1 kgal), or a total water cost saved of $6, assuming $0.005/gallon. Gray water and domestic sewage are treated by an on-site septic drain field.
Results and Achievements
This project supplemented a conventional ground-source heating systems with solar-thermal collectors that boosted the energy-efficiency performance of the HVAC heat pumps and used multiple renewable energy technologies. During daylight hours, a 560-square foot, closed-loop, fixed-tilt, flat-plate solar-thermal collector provides supplemental heat to the HVAC system, provides 100% of the domestic hot water demand, and preheats the ground within the geofield. The hot-side of the solar-thermal collector feeds directly to the indoor HVAC heat pumps (and an 80-gallon domestic hot water heater) and when that demand is a satisfied, any surplus solar-thermal heat energy is routed to the geofield to preheat the ground. The benefits of this piping arrangement cannot be overemphasized. If the geofield were a truck engine, then the solar-thermal collector would be the turbo charger. The HVAC heat pumps operate at efficiencies well above the manufacturer s published data, and the late-summer-late-winter brine temperatures from the geofield were measured at 22% to 25% warmer than those from an adjacent conventional geofield. This design is being shared with the equipment manufacturers, other government agencies and Eastern Washington University.
Energy efficiency for the $1 million renovation project is achieved though diligent attention to detail and the use of simple, readily available, and relatively inexpensive products listed above as the core features to reduce building heat loss and otherwise reduce energy demand. Based on utility bills the maintenance building reduced energy consumption by -32%, or a $2,700 savings in 2010, which contrasts with the predicted 15% reduction. The building is at least 30% more efficient than ASHRAE 90.1-2007 standards. All of the renewable energy systems combined saved approximately 52 metric tons of greenhouse gas emissions annually.
A number of environmental, non-energy benefits resulted directly from implementation of this building renovation project. The design efficiently used empty space in a high bay within the existing building to house the new HVAC mechanical equipment. The geofield and solar-thermal collector are located in pre-disturbed land areas, minimizing removal of trees and shrubs. Native and established non-native plant species conifers were protected as much as possible during construction. Disturbed areas were planted with native grasses and forbs. During construction, more than 50% of construction waste was recycled (diverted from landfills). The renovated maintenance building is equivalent to a Leadership in Energy and Environmental Design (LEED) Silver rating.
Turnbull NWR offers wildlife-oriented recreational and educational opportunities to about 50,000 visitors each year. The visitor area includes exhibits that feature the energy conservation and environmental benefits achieved by this building renovation. Outreach initiatives include the following:
- An interpretive exhibit that shows good environmental stewardship and explains the benefits of the facility's sustainable and energy conservation features to visitors.
- Tours explaining the green building architecture and energy efficiency.
- The refuge website allows access to the solar PV systems to learn more about the amount of renewable energy being generated.
Throughout design, construction, and post construction this project received attention from outside agencies, the local university, and community. The project was recently featured in a Spokane area newspaper. The benefits transfer far into the future and provide a basis for development of similar projects within the U.S. Fish and Wildlife Service, other government agencies, universities, and the community at large. There is a steady dialog among the designers, general contractor, and subcontractors who designed and built this project (and the Services engineers engaged in similar projects), who all pledge to implement these elements into their ongoing and future projects. In addition, the Services Strategic Climate Change Plan calls for achievement of carbon neutrality by 2020. This project demonstrates many of the key elements necessary to move the Service towards that goal.
Turnbull National Wildlife Refuge Maintenance Shop