Integrated School Building Technologies for High Performance Schools
Alder Creek Middle School, Truckee, California
When the Tahoe Truckee Unified School District needed to add a middle
school, they set a goal for the new campus to be as energy efficient as
possible. Built on a 6,000-foot-high plateau in the Lake Tahoe basin,
Truckee is frequently one of the coldest spots in the nation. It
averages 17 feet of snow in the wintertime.
High Performance Features Site: The two-story building has a
reduced foot print to minimize disruption of the environment and to
allow for natural drainage in the meadow. The orientation of the
building takes into account opportunities to maximize daylighting. Its
southern exposure not only allows for good daylighting but also helps
the building capture the benefits of solar heat gain for winter heating.
Lighting: The design team decided early on in the project
planning phase that daylighting in the classroom was a high priority.
This goal was carried throughout the project. The main building is
aligned along an east-west axis to maximize the benefits of daylighting.
The school uses a daylighting system in conjunction with electrical
lighting and controls. All classrooms have full-sized windows to the
ceiling. The ceilings are 10 ft high. The windows contain pre-set U-shaped
horizontal mini blinds housed between triple panes of window glass. This
helps to reflect the daylight off the ceiling and contributes to a more
uniform light level. The paint color was carefully chosen to assist in
providing a good reflectance of light. There is a large central skylight
in the middle of the classroom building that brings additional daylight
into each of the surrounding classrooms through ceiling high
classroom/hallway windows. High-efficiency T5 indirect/direct lighting
with daylight sensors are used when additional light is needed. The
result is classrooms that are energy efficient, and naturally lit
without glare or shadows. The lighting power density of the school is .7
watts per square foot.
Heating: Since wintertime temperatures in Truckee average
between 17 to 42 degrees Fahrenheit, heating costs can be high. The
Alder Creek Middle School uses a ground-source heat pump (GSHP) with
high efficiency pumps for heating and cooling. This is a 300 ton system
that uses 288 six inch diameter wells that extend 315 feet into the
ground. There is a back up boiler in case the supply loop temperature
ever reaches below 42�. To date, the supply loop has not been lower than
46.5�.
Other Energy Efficient Features:
- Energy Star-compliant high-reflectance, high-emissivity roof
- Triple pane, thermally broken window frames
- High efficiency boiler
- High efficiency ground source heat pumps
- Windows that open to provide natural ventilation
- Built into the sloped hillside to maximize use of thermal
insulation
Commissioning: The district retained an independent
commissioning agent to insure the original design intent of the project
was carried out and that systems operate as intended. The agreement
included training of school personnel. The positive experience using a
commissioning agent has resulted in a district policy to commission all
projects.
Water Use: Low-flow water fixtures are installed throughout
the campus, and the school uses a high efficient central boiler for
water heating. The school's athletic field is covered in an artificial
surface that needs no irrigation or chemicals to maintain. The entire
landscaping design minimizes the need for irrigation, and the school
captures storm-water from roofs and hard surfaces, allowing it to seep
into the ground to recharge the local groundwater aquifer.
Sustainable Materials: CHPS recommends using recycled
materials where possible. The new Alder Creek middle school incorporates
ceiling tiles, carpet, insulation, wall boards, cabinets and concrete
products that are durable and low-maintenance, meet EPA-guidelines for
recycled content, and have no residual volatile organic compounds that
can pollute indoor air. More than 50 percent of the school's
construction waste was recycled.
Athletic field: 27,333 old tires (328,000 lbs of chipped
recycled tires) in the athletic field allows the field to be used soon
after a rain. This durable field allows for longer seasonal play and
increased daily use.