High-Performance Building Envelopes: Case Study--Solar Control
May 1, 2007
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Incorporating 27 classrooms in one three-story wing
and 88 faculty offices in a separate four-story wing, CSUSM’s Markstein Hall is
a light-filled, 72,500-square-foot complex. |
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For more information, visit www.ppgideascapes.com.
Studies show that bright buildings can produce bright
students. At the new College of Business Administration at California State
University—San Marcos (CSUSM), they produce significant energy savings, too.
Incorporating 27 classrooms in one three-story wing and 88 faculty offices in a
separate four-story wing, Markstein Hall is a light-filled, 72,500-square-foot
complex designed by Gail Bouvrie, AIA, of AC Martin Partners in Los Angeles.
High-tech accoutrements include teleconferencing equipment in each classroom,
high-speed Internet access wired into every desk, and state-of-the-art video
and acoustical components to facilitate both on-site and distance learning.
Markstein Hall is also one of the first buildings in the country to feature Solarban 70XL glass, a solar control low-e glass from
PPG.
AC Martin Partners was the architectural firm that designed the Joe Serna Jr.
California Environmental Protection Agency Headquarters Building in Sacramento;
a LEED Platinum structure that is regarded as one of the “greenest” high-rise
buildings in the country.
Ken Lewis, AIA, a principal with the firm, was in charge of Markstein Hall. As
a leader of such an environmentally progressive firm, one of Lewis’ goals was
to make Markstein Hall as sustainable as possible, and is also one of the
reasons he chose to make the building one of the first in the country to capitalize
on the performance and aesthetic benefits of low-e glass.
More Light, Less Heat
Introduced at the Greenbuild 2005 International
Conference and Expo, Solarban 70XL glass
constitutes an advance in the architectural glass industry for two reasons.
First is the glass’ solar control performance. Combined with traditional clear
glass in a conventional one-inch insulating glass unit, Solarban 70XL glass blocks up to 73 percent of the sun’s
solar energy, while transmitting more than 63 percent of its visible light, the
company reports, resulting in a Light-to-Solar Gain (LSG) ratio of
2.33.
Second is the glass’ transparency.
The architectural glass combines solar control with a clear glass aesthetic.
According to the company, before the introduction of Solarban 70XL glass, the highest-performing non-tinted
solar control, low-e glass transmitted 70 percent of the sun’s visible light in
a one-inch insulating glass unit, while blocking only 56 percent of its solar
energy. The resulting LSG of 1.84 was 21 percent less than that of Solarban 70XL glass.
The potential energy savings associated with Solarban 70XL glass was highlighted in a recent study
conducted by an independent energy and environmental research firm. The study
compared the energy performance of six glazing configurations, including
several competing solar control low-e glasses, on three common building types
in nine different U.S climates. It showed that architects and building owners
could cut capital investment in a building’s cooling plant by up to 26 percent
when substituting Solarban 70XL glass
for other solar control low-e glasses. The study also showed that building
owners could anticipate ongoing energy savings of 3 to 5 percent annually for
buildings constructed with Solarban
70XL glass.
Real World Performance at San Marcos
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A
comprehensive energy management system has helped Markstein Hall realize better
than required energy efficiency. |
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Markstein
Hall on the campus of CSU-San Marcos has been open only a few months.
Consequently, it is not yet possible to compare its annual energy savings with
those cited in the study above but, thanks in part to low-e glass, building
owners were able to realize a significant and immediate payback on their
initial building investment.
Lewis estimates that by specifying the glass for Markstein Hall, he was able to
lower mechanical costs for the building by $2.00 to $3.00 per square-foot.
These savings were related primarily to a lower chilling capacity requirement,
as well as smaller fan sizes and ducts.
Yet, these initial cost reductions were just the beginning. Working closely
with San Diego Gas & Electric (SDG&E), Lewis and his building team were
able to earn more than $100,000 in incentives through the utility’s Savings By
Design program. According to program administrators, Markstein Hall is expected
to generate annual energy savings of almost 500,000 kilowatt-hours, or
approximately $75,000 per year at current energy prices. That reduction is
almost 35 percent better than is required under Title 24, California’s Energy
Efficiency Standards for Residential and Non-Residential Buildings. As a result,
the project team earned almost $120,000 in Savings By Design incentives,
including $90,000 paid directly to the building owner and another $30,000
allocated to the design team.
Markstein
Hall’s energy efficiency can be attributed to a comprehensive energy management
system. For example, a demand-control ventilation system takes advantages of
the local ocean breezes, allowing up to 100 percent of the outside air into the
building to control cooling and promote off-gassing. The system even includes carbon
dioxide sensors that can trigger fresh air intake, helping students to stay
alert during their studies.
Another highlight is the specification of multi-switched, multi-level lighting
fixtures that combine compact fluorescent, linear fluorescent, metal
halide and other fixtures with abundant natural light to provide direct and
indirect light. As a result, lighting power density in Markstein Hall averages
1.00 watts per square foot, which is 15 percent less than the minimum threshold
required under Title 24.
Not only does the natural light and fresh air contribute to energy savings; the
combination is expected to enhance student performance as well.
Looking Ahead
With
Markstein Hall complete and occupied, Lewis has already begun work on an even
bigger campus building. In late 2005, the University of California held its
first classes at Merced, a new campus just outside Fresno. The first American
research university built in the 21st century, UC-Merced has ambitious goals
for sustainability. In fact, the school wants to achieve energy usage that is
half that of the other nine campuses throughout the University of California
system.
The challenge fits in well with what Lewis views as a personal and firm-wide
obligation to preserve and protect the environment.
“At AC Martin, one of our core beliefs is that better buildings make for a
better environment,” Lewis said. “The issue of sustainability is important to
us and we take it seriously because, as architects, we consider ourselves
stewards of the earth.”
Based on that philosophy and a proven track record for environmentally
sustainable design, Lewis’ firm was chosen to design the new Social Sciences
and Management building at UC-Merced. The 90,000 square-foot building, which is
scheduled to open in fall 2009, will also feature low-e glass—chosen for its
appearance as well as its daylighting characteristics and environmental
performance.
“I really like the look of transparent glass,” Lewis said. “It makes design
much more interesting because it gives natural depth and dimensional qualities
to a building. At San Marcos, the brightness and openness of the building are
also critical to fostering a more pleasant and energetic learning environment.”
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