A new technical resource
is now available to guide owners and architects toward improved energy
performance in office buildings of up to 20,000 square feet—specifically,
30 percent better performance than equivalent buildings built to the
minimums prescribed by ANSI/ASHRAE/IESNA Standard 90.1-1999. Advanced
Energy Design Guide for Small Office Buildings offers an integrated
design-construction-occupancy process, recommendations and case studies
by climate zone, and specific recommendations for implementation.
Concentrating on four basic building systems—envelope, lighting,
HVAC, and service-water heating (with bonus savings for exterior and
parking-lot lighting and plug load)—the new energy design guide
shows how straightforward, field-proven design strategies give clients
what they are demanding as the cost of energy skyrockets: more efficient
buildings.
Developed
by the American Society of Heating, Refrigerating and Air-Conditioning
Engineers; The AIA; Illuminating Engineering Society of North America;
New Buildings Institute; and U.S. Department of Energy, the Advanced
Energy Design Guide for Small Office Buildings is the first
in a planned series of building-type-specific guidelines for significantly
exceeding the minimum standards in energy efficiency. The next guideline,
scheduled for release later in 2005, will focus on retail facilities,
with at least four more guides anticipated through 2008.
Energy goals and strategies
At the heart of the Advanced Energy
Design Guide is identification of
conservation goals and strategies. The 30 percent reduction in energy
use over ANSI/ASHRAE/IESNA Standard 90.1-1999 include:
- Building envelope: roofs, walls, floors, slabs, doors, vertical
glazing, and skylights
- Lighting: daylighting/interior/electric lighting, and controls
- HVAC equipment and systems: cooling and heating equipment efficiencies,
supply fans, ventilation control, and ducts
- Service water heating: equipment efficiencies and pipe insulation
- Bonus savings: exterior façade lighting, parking lot lighting,
and plug loads.
Specifically, for reducing loads on energy-using systems, strategies
and recommendations the Guide offers include:
- Using Energy Star equipment and “sleep-mode” controls
on office equipment
- Educating occupants
- Maximizing daylight (including
skylights and north-oriented clerestories)
- Incorporating: efficient
electric lighting, separate lighting controls near windows
- Automatic
off switches
- Beneficial building form and orientation
- Maximal east/west and north/south
window orientation for regional climate conditions
- Optimal specification
of solar heat gain coefficient and external shading for glazing
- Vegetation
and other shading strategies to control solar heat gain and glare
- Increased
insulation of opaque surfaces
- Strategic specification of roof-surface
reflectance and emittance
- Continuous air barrier
- Energy exchanges between exhaust air and preconditioned
fresh air
- Increased thermal mass
- Insulated ductwork that is kept inside the
building envelope
- Screened operable windows into the building layout
so that it optimizes cross ventilation
- Demand-controlled ventilation
and shut-off dampers for temporarily unoccupied areas
- Tightly
sealed envelope-penetration joints and seams
- High-efficiency motors
- Dividing of buildings into thermal zones with
time-of-day scheduling for temperature setback and setup and pre-occupancy
purges
- Point-of-use water-heating and air-conditioning units to minimize
pipe distribution.
Considered climate zones span from cold to hot
The Guide offers specific prescriptive performance criteria for eight
climate zones ranging from subtropical to arctic, including a case
study for each. In addition to the energy-efficient aspects of each
case-study project are descriptions of their other environmentally
sensitive design features, with many of the buildings presented having
U.S. Green Building Council LEED™ certification. The two examples
presented here are the SpawGlass Construction Corporate Headquarters,
Houston (Zone 2), designed by Kirksey Architecture, and Hartley Nature
Center, Duluth, Minn. (Zone 7), designed by Stanius Johnson Architects.
SpawGlass Construction Corporate Headquarters. Located in Zone 2, which
has extreme summer temperatures, SpawGlass Construction Corporate Headquarters
houses the operations of one of Houston’s most successful contracting
firms. The building is also the first LEED-certified building in Houston.
The single-story, concrete tilt wall, 20,000-square-foot structure is
located on a generous four-acre site. Designed by Kirksey, the building
features a lobby/conferencing area, enclosed private offices, and open-plan
support space.
The building makes generous use of natural light; windows located throughout
the building provide daylight and views for more than 75 percent of all
the occupied spaces. The project also employs on-site storm-water retention
and filtration, water efficiency, and native landscaping. In addition,
vegetated swales and bio-retention basins were designed to reduce the
rate of storm-water runoff and remove water contaminants.
An Energy Star-compliant roof system and paving surfaces with a high
reflectance help minimize heat absorbed on the site. Water-saving fixtures
include motion-sensor lavatory faucets, waterless urinals, and low-flow
kitchen faucets and shower heads. Energy-saving strategies also include
the use of occupancy-sensor lighting, harmonic transformers, low-e
insulated glazing, east-west orientation, appropriate glazing locations,
and an efficient HVAC system.
Hartley Nature Center. The Hartley Nature Center offers environmental
education and outdoor recreation programs for adults and children, and
the design team strove to create a new center that supports the learning
process. This building’s many sustainable features include extensive
daylighting and ventilation; renewable, efficient energy systems for
heating and cooling; and materials with recycled content.
The center, built on a south-facing slope, maximizes exposure to sunlight
that allows incorporation of passive solar features, natural lighting,
ground-source heat pumps, and solar walls. Solar panels mounted on the
roof can produce 11.8 kilowatts of electrical power. The system connects
directly to Minnesota Power’s grid; Minnesota Power buys any excess
electricity generated.
In addition to using renewable energy, the Hartley Nature Center uses
energy-conserving methods such as insulated concrete forms, heat-recovery
ventilation, and energy-system sensors that track energy use as well
as energy produced by the solar panels.
The nature center also uses sustainable and environmentally preferable
building materials, such as 100 percent recycled-content roof shingles,
recycled-content carpet tiles, natural-based wood glaze, and non-PVC
materials. The center also constructed a pervious paving system on the
walkways to minimize storm-water runoff.
Copyright 2005 The American Institute of Architects.
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