The Power Of Zero
- By Pauline Souza
- November 1st, 2016
Schools in the U.S. spend billions each year on energy. With such high energy costs and the growing
concern for our environment, there is a need to implement
high-performing and net-zero energy strategies into educational
design. While net zero has traditionally been seen as cost prohibitive,
The Stevens Library at Sacred Heart Schools in Atherton, Calif.,
the first school building in California to achieve Net Zero Energy
Building Certification from the International Living Future Institute,
demonstrates that net zero can be achieved within a conventional
budget in attractive and inspiring ways, while teaching students
about resource conservation and social responsibility.
Commitment to stewardship — The school wanted
the library, the learning hub for the K–8 campus, to reflect its
environmental stance while instilling in students, faculty and
staff a sense of ongoing stewardship. The school’s commitment
to teaching students about conservation and creation through
a hands-on learning approach motivated the their building
committee to take on the ambitious goals for this project and
provided the confidence that a net-zero-performing design
approach was practical without unusual risk.
Communication is key — Communication and managing
expectations was key to the success. The architects and engineers
worked closely with the school on the operational strategies and
construction program. In doing so, the library was able to meet the
budget demands while reaching a ZNE performance level.
Cost-effective solution — The school’s modest, constrained
budget necessitated a streamlined design that would be conducive to
renewable energy systems. The result is a simple architectural design
with a flat roofline that accommodates solar photovoltaic panels and
a strong building envelope that reduces energy loads. The design also
took advantage of natural ventilation and maximized daylighting.
Energy-saving strategies — The library’s design focuses on
energy-saving and water-saving strategies, with a design that visibly
highlights the links between energy and water through a glazed
exterior showcase space. Below are examples of low energy design
strategies that can be modeled for educational ZNE projects.
- Solar Panels —
The high-efficiency photovoltaic system
provides all the library’s needed energy. The 250-watt panels were
placed horizontally, in a densely packed arrangement.
- Glazing — The high-performing glazing is color neutral low-e
glazing which provides a low U-value equal to 0.28, a solar heat
coefficient of 0.28 and a visible light transmittance of 64 percent,
ultimately helping reduce energy loads.
- Insulation — To further reduce energy loads, rigid insulation
was added to the building envelope to increase its performance.
The resultant performative building envelope is highly insulated
with R-15 walls and R-38 white reflective roof.
- Operable Windows — Carefully placed operable windows
were positioned to take advantage of local breezes and maximize
- HVAC — A package unit with an efficient air-to-air heat pump
that had both indirect and direct evaporative cooling sections was
used. For those rare, extreme temperature days, a compressor was
added to the unit to provide mechanical cooling.
- Light Sensors — High-efficiency linear fluorescent direct and
indirect light fixtures are continuously dimmed through daylight
and occupancy sensors in response to available daylight, although
dimming can be overridden by staff.
- Solar Tubes — A number of mechanized solar tubes at the
roof, carefully located between the PV panels, provide top lighting
to maximize natural light in order to reduce energy loads.
- Rainwater — The harvested rainwater is filtered and stored
in a 3,000-gallon tank. A system of pumps feeds the irrigation
system, and in turn, a grey water system that collects water from
all the buildings on the quad, adequately treats the water so that it
can be used to flush toilets in all buildings.
Design as an educational resource — In an effort to bring
the school’s sustainable story to the forefront, the energy-systems are
placed on display as learning tools. The rainwater management and
grey water waste treatment systems are made visible by a folding glass
door, providing access for use in educational efforts. Environmental
graphics are integrated into the glass door, illustrating the water
story and potable water availability. Additional dynamic signage
highlighting photovoltaic capture, energy usage and daily trends, are
on display within the library for the public to observe.
Net zero is an attainable goal. By implementing low-cost design
strategies and exposing the building’s sustainable strategies,
schools can teach students about conservation and help them build
good habits at a young age.
This article originally appeared in the November 2016 issue of School Planning & Management.
Pauline Souza, AIA, LEED Fellow, LEED-AP BD+C is a WRNS Studio Partner and director of Sustainability. She also is National Green Schools committee chair — Center for Green Schools and a Green Schools advocate for the USGBC.