Fossil Ridge High School was designed to use 60% less energy than a comparable, baseline high school. The building was expected to reduce energy costs by about one-third relative to comparable schools in the district, saving $60,000 each year.
The building envelope is well-insulated and has high thermal capacity (the exterior walls are one foot thick). A white roof reflects solar radiation, further reducing the internal cooling load.
The building was oriented to maximize solar exposure while minimizing glare and heat gain. Daylight provides about 60% of needed light, with well-placed, shaded windows and tubular skylights bringing light into the interior of the building. Daylight and motion sensors ensure that artificial lights are dimmed or turned off when daylight is adequate; all dimmers have manual overrides, however, allowing occupants to control the lighting to meet their needs.
High-efficiency condensing boilers and a heat-recovery system reduce the energy use of the mechanical systems, while sensors ensure that the heating and cooling systems are turned off when windows are opened. A thermal energy storage system makes and stores ice during off-peak hours; this ice is used to cool the building during the day. A 5.2-kilowatt photovoltaic system provides clean energy while shading windows from unwanted heat gain.
Energy use in the building has varied due to different uses: the building contained two separate schools during some years, with only one school in others. A difference between predicted and actual energy use is likely due to kitchen equipment and exterior lighting, neither of which was included in the energy simulation.
The photovoltaic system can provide emergency power for the facility.
Annual Purchased Energy Use Fuel Quantity Cost($) MMBtu kBtu/ft2 $/ft2 Electricity 1,700,000 kWh $90,770.05 5,800 19.6 $0.31 Natural Gas 59,500 therms $49,215.52 5,950 20.1 $0.17
Total Annual Building Energy Consumption
Fuel Cost MMBtu kBtu/ft2 $/ft2 Total Purchased $139,985.57 11,700 39.5 $0.47 Grand Total $139,985.57 11,700 39.5 $0.47
Peak Power Fuel Quantity English Electricity (Summer) 428 kW 1.44 W/ft² Electricity (Winter) 524 kW 1.77 W/ft²
Data Sources & Reliability
Electricity bills come form Fort Collins Utilities, and gas bills come from Tiger Natural Gas.
The utility data does not include electricity produced by the photovoltaic system, which was anticipated to provide about 0.4% of the school's electricity; data for this system is unavailable.
- Achieve a whole-wall R-value of 15 or greater
Solar Cooling Loads
- Use light-colored exterior walls and roofs
- Orient the building properly
Daylighting for Energy Efficiency
- Orient the floor plan on an east-west axis for best use of daylighting
- Use building elements to redirect daylight and control glare
- Use large interior windows to increase daylighting penetration
- Use skylights for daylighting
- Use light pipes and/or active tracking skylights for daylighting
Hot Water Loads
- Use water-efficient faucets
Non-Solar Cooling Loads
- Use operable windows
- Commission the HVAC system
- Use building-integrated photovoltaics (PV) to generate electricity on-site
- Use high-efficiency, condensing oil or gas boilers and furnaces
- Use heat-recovery ventilation
- Use occupancy sensors
- Use dimming switches
HVAC Controls and Zoning
- Provide sufficient sensors and control logic
- Wall Insulation