Westcave Preserve Env. Learning Center

Photo credit: Greg Hursley

Energy

This project was designed as a model of flexible energy use based on user need. Compared to the powerboat design of conventional buildings, this project was designed as a sailboat, where mechanical systems operate only when natural solutions are not available. The building was designed to be used as a zero-energy-consumption “pavilion” when large school groups visit. The ground-source heating and cooling system is used to condition the space only when the weather is too humid (in the summer) or too cold (in the winter). The project focuses on the use of sustainable strategies such as natural ventilation and daylighting, passive solar design to provide comfort and light without grid power, and education.

Users are encouraged through an interactive educational exhibit to help keep the building's energy use below the 1,700 watts provided by the onsite photovoltaic (PV) array; this is possible much of the time. The PV system provides 300 to 350 kWh of energy per month, and the building generally uses between 1,500 and 2,500 kWh per month. Much of this energy use occurs when the building is used at night by community groups. During school field trips, the building uses very little power due to the use of outdoor areas as educational spaces.

The PV system's performance is monitored, and its output is displayed next to the power used from the grid. Switches for the lights, air-conditioning, and fans are located adjacent to the monitors as an interactive exhibit. Students are asked “Do we need these lights on?,” and “Do we need the air conditioning on?” As students turn the systems off, they see that they do quite well with no energy or with only what is provided by the solar array. The display also includes a joystick to operate the PV tracker system. This educational display has been effective in curbing energy use.

The building is aligned with the earth’s axis (true north-south on the western meridian), and a meridian line and sky map are embedded in the floor as educational exhibits. The building design also responds to this orientation with very large overhangs on the east and west, a covered exterior shelter on the north, and small overhangs on the south for passive heating in the classroom. The floor also illustrates "nature's numbers," featuring the enigmatic relationship between the Fibonacci series, golden rectangle, logarithmic curve, and form of a 90-million year old ammonite.

The cooling systems are staged as needed. The building section and operable windows, high windows at the cupola, and the fan system create and reinforce passive cooling via the chimney effect. South and southwest breezes are funneled into the building in spring and summer, and attic fans on each end of the high clerestory force circulation when there are no breezes. Two small ground-source heat pumps cool the space on hot, humid days with large crowds.

Insulated low-emissivity glass was used except at the lower daylighting clerestories along the perimeter where clear glass was used. An operable system was employed for the lower windows, and auto-controlled awnings were installed at the high roof clerestory for passive natural ventilation. The building's roof and walls are insulated to R-30.

Daylighting is provided by continuous perimeter clerestory glazing. Electric lighting is provided by uplights with fluorescent T-5 bulbs. Low-voltage task lighting is provided for the exhibit walls and blackboard walls.

Green Strategies

• Ground-coupled Systems
  • Use ground-source heat pumps as a source for heating and cooling
• Solar Cooling Loads
  • Orient the building properly
  • Shade south windows with overhangs
• Daylighting for Energy Efficiency
  • Design an open floor plan to allow exterior daylighting to penetrate the interior
  • Use large exterior windows and high ceilings to increase daylighting
• Non-Solar Cooling Loads
  • Provide an open floor plan and openings located to catch prevailing breezes
  • Use operable windows
• Light Levels
  • Use light levels appropriate for different tasks
• Photovoltaics
  • Use a photovoltaic (PV) system to generate electricity on-site
• Light Sources
  • Use high-efficacy T-5 fluorescent lamps

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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 .