Fresh Air and Daylight: Designing Natural Environments

Manufacturers are providing opportunities for fresh air in buildings while integrating daylighting techniques for increased energy efficiency.
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Sponsored by EFCO Corporation, La Cantina Doors, Milgard Windows & Doors, Nana Wall Systems, Inc., OpenAire Inc., Pella® Windows and Doors, Solatube International
Celeste Novak, AIA, LEED AP, En\compass Architecture

Design Opportunities

It is no surprise that humans thrive in environments that are linked to nature. Among The American Institute of Architects Committee on the Environment's (COTE) 10 measures of sustainable design are principles that encourage architects to use bioclimatic design and provide daylight, natural ventilation and views to nature.

 

IslandWood Environmental Center, Bainbridge Island, WA
"Operable windows are combined with solar strategies to heat and cool this Washington State building eight months each year."
-Terry Zeimetz, Pella® Windows and Doors. 

(Images courtesy of Mithun Architects)

 

 

As an example, IslandWood is an outdoor environmental center designed by Mithun Architects +Designers+Planners. Designers for this 70,000 sf facility in Washington State used Thermal Analysis System (T.A.S.) modeling to integrate the building form and fenestration in order to minimize heating and cooling through mechanical systems. The placement of smaller windows on the windward side of the walls used the stack effect to draw air through the building and up into the operable clerestory windows. Interior walls were designed to aid air-flow through the building. Designers continued to model ventilation and airflow throughout the schematic design.

More windows require more design initiatives for sun control. Commercial window systems can also provide custom-designed shading devices to control glare, such as those displayed on Cosby Road High School, located in Midlothian, VA. Designers may wish to employ a combination of shading strategies, which may mean custom exterior light shades combined with interior light shelves in the same window system.

Furthermore, architects such as Cheryl Walker, AIA, LEED AP of Gant Huberman Architects, are using a wide variety of integrated design approaches to daylight.  Walker states, "Increasingly, our firm is integrating daylighting strategies into buildings. When truly integrated with the building energy systems, features such as performance glazing, solar shades, light shelves, and roof monitors routinely contribute to a 20 to 30 percent reduction in the building's energy consumption. The quality of the daylit interior is frequently our clients' favorite feature of their project."

To meet the newest environmental challenges, manufacturers are investigating the next generation of windows with even greater energy performance. According to Joe Rapolla, representative from La Cantina Doors, "The future is in the glass and multi-coated technologies." Maureen Faccia, Director of Marketing at Milgard Windows & Doors adds, "Smart window design, frame construction and materials, as well as insulated glass units can exceed ENERGY STAR performance standards by up to 26 percent."

In addition, some companies are introducing tubular daylighting devices, which allow for horizontal and vertical runs of over 100 feet, providing even more opportunities for substitutions of electric lighting fixtures. The good news is that there will be more products available for architects meeting the American Institute of Architect's call to reduce energy consumption in buildings by the year 2030.

Fresh Air

 

Folding glass doors make transitions between nature and the interior invisible.

Photo courtesy of La Cantina Doors

 

 

Most architects know that building occupants complain if their space is too cold, too hot, too humid or too drafty. Mechanical systems are designed to meet average temperatures within a designated human comfort zone. These systems limit personal controls for comfort, and often are compromised when someone opens a window to let in fresh air. Providing fresh air in large structures can be problematic without integrating the aspects of daylight design with ventilation strategies.

 

Energy-efficient window choices provide energy savings and a dramatic view from this waterfront home.

Photo courtesy of Milgard Windows & Doors

 

 

The U.S. Green Building Council reference guides for LEED recommend that designers follow the Carbon Trust "Good Practice Guide 237" (1998) for information on how to naturally ventilate an occupied space. Designers are required to use computer models and provide diagrams and calculations to demonstrate that ventilation designs meet the recommendations in the Chartered Institution of Building Services Engineers (CIBSE) Manual 10:2005,  Natural ventilation in non-domestic buildings.

Today, the primary reference for ventilation strategies is the American Society for Heating and Refrigerating Engineers (ASHRAE) 62.1-2004, paragraph 5.1, which describes the latest ventilation guidelines. Designers follow ASHRAE standards to design for comfort zones, as illustrated in ASHRAE's bioclimatic chart. Design components that are necessary to achieve indoor comfort based on the outdoor conditions are determined through a climate analysis of the site's location.

 

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Originally published in GreenSource
Originally published in July 2008

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