Sidwell Friends Middle School

Photo credit: © Barry Halkin

Energy

Energy modeling indicates that the building will use 60% less energy than a comparable building designed in minimal compliance with ASHRAE 90.1-1999.

The project team worked to minimize the number of days when heat and humidity make the indoor environment uncomfortable without mechanical air conditioning. This drove the team to limit, through screening and shading devices, direct solar penetration and placed a premium on robust natural and mechanically assisted ventilation systems.

The building's exterior sunscreens were designed to balance thermal performance with optimum daylighting. No screens were needed on the building's north side, where high windows admit diffuse light. On the south side, screens were placed horizontally above the windows. On the east and west sides, shades were arrayed vertically and angled at 51° north of west for minimal heat gain and maximum penetration of daylight during the early afternoon.

Behind the wood shading is a wood rainscreen designed to shed most water but remain open to the movement of air. A lightshelf incorporated into the façade transmits daylight deep into the building while shading the corridors from direct sun. In addition, the roof, walls, and windows perform over 200% better than the minimums set by the ASHRAE standard, and the vegetated roof provides shading and enhances the roof's insulation value.

High-efficiency lighting minimizes electricity use. Occupancy sensors ensure that electric lighting is shut off when rooms are unoccupied, and automatically controlled dimming ballasts ensure that electric lighting is used only when daylight is insufficient.

Additional design features included to maximize the project's energy efficiency include solar ventilation chimneys, a dedicated outdoor-air ventilation system, and a photovoltaic array that generates 5% of the electrical demand for the building.

Rather than develop a utility plant for this building alone, a central plant was created to serve the entire campus, allowing greater control of energy resources and demonstrating responsible energy use to students. Boilers and chillers in the utility plant were selected for efficiency and are controlled to maximize efficiency when operated at either low loads or heavy loads. All pumps associated with the chilled and hot water systems have variable-speed drives.

Data Sources & Reliability

Reliability
The energy data above was prepared from the project's LEED submittal. For LEED credit, the project team separated the new portion of the building from the renovated portion and performed energy modeling on each. These two models were combined to enter the data shown above.

Green Strategies

• Solar Cooling Loads
  • Shade south windows with overhangs
• Daylighting for Energy Efficiency
  • Use south-facing windows for daylighting
  • Use large interior windows to increase daylighting penetration
• Non-Solar Cooling Loads
  • Use operable windows
  • Use ceiling fans to improve comfort at higher temperatures
• Cooling Systems
  • Commission the HVAC system
• Photovoltaics
  • Use a photovoltaic (PV) system to generate electricity on-site
• Other Energy Sources
  • Develop or take advantage of district heating
• Ventilation Systems
  • Use heat-recovery ventilation
• Lighting Controls
  • Use modulating photoelectric daylight sensors
  • Use occupancy sensors
• HVAC Distribution Systems
  • Use variable frequency drives for fans
• Roof Insulation
  • Achieve a whole-roof R-value greater than R-35

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Our thanks to the ENERGY STAR program of the U.S. Environmental Protection Agency, and to the U.S. Department of Energy, and to BuildingGreen, Inc. for hosting the submission and judging forms.

For more information about the AIA/COTE Top Ten Green Projects, contact AIA/COTE. For help on how to use this Web site, contact .