Energy

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.

Energy security

The photovoltaic system can provide emergency power for the facility.

 

Select Energy Data Set: Actual--utility bills: 2007 "FRHS Utility Bills" Simulation--90.1 regulated loads only: 2004 "FRHS Energy Model" Actual--utility bills: 2005 "FRHS Utility Bills" Actual--utility bills: 2006 "FRHS Utility Bills" Units: English Metric

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

Utility bills
Electricity bills come form Fort Collins Utilities, and gas bills come from Tiger Natural Gas.

Reliability
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.

 

Green Strategies

• Wall Insulation
  • 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
• Cooling Systems
  • Commission the HVAC system
• Photovoltaics
  • Use building-integrated photovoltaics (PV) to generate electricity on-site
• Heating Systems
  • Use high-efficiency, condensing oil or gas boilers and furnaces
• Ventilation Systems
  • Use heat-recovery ventilation
• Lighting Controls
  • Use occupancy sensors
  • Use dimming switches
• HVAC Controls and Zoning
  • Provide sufficient sensors and control logic