CASE STUDIES

Project: Chabot College Community and Student Services Center, Hayward, CA

Architect: tBP/Architecture

Glazing Contractor: Capital Glass

Electrochromics: SAGE Electrochromics

CASE STUDY FEATURES:
Electrochromic Glazing
Maximized Daylight
Natural Ventilation
Radiant Heating & Cooling

 

Typical Glazing Properties:
Electrochromic insulating glass
U-factor=0.28
SHGC=0.09 (tinted state)
SHGC=0.48 (clear state)
VT=0.02 (tinted state)
VT=0.62 (clear state)

Chabot College Community and Student Services Center

Chabot College's Community and Student Services Center (CSSC) is a visual centerpiece to the college and community and services nearly 15,000 students, staff and faculty. The design of CSSC uses a number of sustainable design strategies including an atrium that optimizes daylighting and energy efficiency, radiant in-floor air heating and cooling, and natural ventilation.

CSSC's atrium includes a 2,900 square foot curtain wall that faces south and west—providing unobstructed views to the campus, providing natural light deep into interior space, and reducing the need for artificial light. The orientation of the atrium posed the possible challenges of too much glare and too much heat from the sun. The design challenge was to maintain the view to the outside while also maintaining thermal comfort of the building's occupants. To deal with this challenge, the design team chose to use dynamic glazing for the atrium. The overall design of the atrium delivers exceptional energy efficiency by the use of an automated electrochromic glazing system, radiant heating/cooling, and natural ventilation.

The electrochromic glazing system automatically tints throughout the day to control glare and solar heat gain through the atrium curtain wall. This system features six automated zones integrated into the building's environmental management system. The glass changes state (darkens or clears) by zone based on pre-defined air temperature thresholds. There is a manual override if additional adjustments are necessary.

The Chabot College Community and Student Services Center's atrium uses SageGlass tintable windows to control the glare and solar heat gain into the space. The top image shows the glass in its clear state and the bottom image shows it in its tinted state. Photos courtesy of SAGE Electrochromics; Copyright Eric Sahlin Photography

Radiant heating/cooling and natural ventilation control the air temperature in the space. The electrochromic glazing adjusts to the flow of air through the ventilation scoops on the roof and thermal heating/cooling of the radiate slab. As air is brought into the building over the roof, the amount of heat transmitting through the glass works with the heating/cooling of the slab to generate airflow through the atrium space. Depending on the defined zone threshold, air is heated or cooled via the thermal slab and then allowed to rise out of the building through air scoops without the use of an air-ducted ventilation system. Due to the unique ventilation system and SageGlass tintable windows, no HVAC system was required in the atrium space which helps to save both money and energy.

Sources:
SAGE Electrochromics. "Case Study: Chabot College." 2011

SAGE Electrochromics. "SAGE Electrochromics 'Dynamic Glass' Selected for Chabot College's Community & Student Services Center." Press Release. May 24, 2010.

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