posted on August 15, 2013 |
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Fireside Elementary School in Phoenix uses the sun to generate 93% of the energy it uses. Not so challenging in sunny Arizona, you might think. How about this? Its rainwater harvesting system meets almost all of its water needs - including landscape irrigation. In the arid southwest, that’s a pretty impressive feat.
Designed by DLR Group, an architecture firm that specializes in sustainable design, the school’s 88,000 square foot (8200 square meter) building includes ample daylighting, green building materials, energy-efficient mechanical systems, photovoltaic panels, rainwater harvesting, and solar water heating.
As with all good sustainable designs, DLR started this project by making the building and its systems as energy-efficient as possible. A watt saved is just as good as a watt generated, and it’s almost always cheaper. Insulated Concrete Form (ICF) walls rated at R-22 provide a solid thermal and acoustical boundary. Low-e glazing on the windows allows visible light to pass through while blocking UV and IR radiation, keeping the building bright and cool at the same time. Efficient HVAC systems and programmable thermostats regulate temperature while using minimal energy. Solatube skylights provide efficient daylighting from above. (Natural daylighting not only provides free light, it’s also been demonstrated to increase productivity and learning.) Large skylights illuminate the hallways. Overhangs on the south side of the building shade the windows from direct sunlight, helping the school to stay cool. nLight networked lighting controls have sensors that measure ambient light and room occupancy, turning electric lighting on and off depending on needs. This maintains a constant 50 foot candles of light in all occupied rooms. The passive lighting and cooling, coupled with the energy-efficient design, cut the amount of energy that the school uses by almost half when compared to other buildings of similar size and function.
Water heating is achieved with 97 square feet (9 square meters) of flat-plate collectors. To generate the school’s electricity, photovoltaic arrays are mounted in the parking lots, providing shade for cars as well as 260 kW of power. The school’s playground is also shaded by an 80 kW PV array. Why weren't the PV panels mounted on the roof? They would have interfered with the skylights. Besides, shading the cars in the parking lot reduces the amount of AC that the cars will use after school, and shading the playground protects the kids from excessive heat and direct UV light. Together, the PV arrays and solar water heaters generate 93% of the energy that the school needs.
The school’s water reclamation system includes a 4200 gallon (15.9 kiloliter) open tank that collects rainwater and roof runoff. This tank is located at the front of the building to raise awareness of water harvesting. (It is an educational center, after all.) Three more closed tanks collect nearly 27000 gallons (102 kiloliters) of roof runoff. All water is filtered before use. City water serves as a backup during times of extreme drought.
And of course, the school is also a living laboratory of energy efficient design and sustainable energy production. It’s loaded with built-in STEM (science, technology, engineering, math) lessons that benefit the students and the community.
The cost of the building was $13.5 million - roughly $152 per square foot ($1640 per square meter). The district received just over $100k in energy efficiency rebates from the utility company. The school just opened a year ago and is currently running at 75% student capacity. The real test of its efficient design and power generating abilities will come over the next few years when it reaches full capacity. While the economic factors and payback period may be debatable, one thing is certain: this school and buildings like it will lead the way towards a more sustainable world. This is a school that educates in more ways than one, making it a worthy investment in the future.
Photo: DLR Group