UT School of Nursing and Student Center

Photo credit: Hester + Hardaway

Energy

The building is expected to use 80% less energy per square foot than the adjacent UT School of Public Health building, built in 1977, and 41% less energy than a conventional, minimally code-compliant building. This reduction in energy use is expected to save $38,000 annually.

The building envelope, lighting, and mechanical systems were all designed to minimize cooling loads. Strategies include high-performance glazing and shading devices; high-efficiency, right-sized mechanical systems; daylit work spaces with dimming devices to reduce lighting loads; and operable windows.

The site available was not ideal from a solar standpoint and required the building’s long facades to face due east and west. This presented unique challenges and opportunities to the design team. To address this undesirable orientation, the design team implemented numerous passive strategies to minimize direct solar heat gain and maximize the use of natural light. The result is a facility that tells the story of the sun’s path through the sky. The need to reduce cooling loads is expressed on each surface of the building.

Each facade was carefully considered, using daylight modeling and analysis, to minimize heat gain and glare; glazing qualities such as emissivity, U-value, and spectral selectivity, as well as shading and light-reflecting devices, were selected based on application. Aluminum lightshelves on the south and west facades reflect daylight and reduce glare, and translucent sailcloth fins and lightshelves perform the same function on the east facade. Atria with translucent baffles diffuse light in the interior spaces of the building's top three levels.

The building utilizes a high-performance facade, modeled on rainscreen-principle design, with a high-performance vapor barrier and a highly insulated wall section. The highly insulated roof has a high-reflectivity, low-emissivity membrane, reducing heat gain and, therefore, reducing the internal cooling load.

Operable windows installed throughout the building can be open approximately 134 days each year in the Houston climate. Exit stairs were moved to the exterior of the building and are naturally ventilated. A major breezeway provides naturally cool outdoor space, harnessing the venturi effect and the cooler ambient temperatures of the park to the east to provide relief to people in the hot summer sun.

Plenum underfloor air distribution with low-face-velocity coils reduces the horsepower needed to run the air-handling units and improves flexibility. Generously sized hydronic piping (along with a 16°F chilled-water temperature rise) significantly reduces required pumping horsepower.

Critical zone reset on outside ventilation air and carbon dioxide sensors minimize ventilation loads. A heat-pipe heat-recovery system recovers heat from the general exhaust system to preheat or precool outside air.

Condensing hot water boilers are used for seasonally heating outside air in lieu of superheated steam at 250 pounds per square inch gauge (psig) from the campus distribution system.

Mechanical rooms were limited to 100 feet above grade to eliminate friction losses from pressure reducing valves needed for the campus system.

Extensive data-collection systems collect historical data (at one-minute intervals on critical load points) to monitor and track building performance.

A steel support structure with ideal orientation was installed on the roof to support the installation of photovoltaic panels in the future. Due to budget constraints, they are not included in the project at this time.

Energy security

Peak electrical demand is minimized through the use of efficient mechanical systems and lighting controls that allow daylight to become the primary ambient light source during the day, when building use is highest. Occupancy sensors are also used throughout the facility to turn lights off when they are not needed. Operable windows provide natural ventilation to reduce energy usage and maximize user comfort during acceptable weather.

Because the facility is a critical-use facility on the Texas Medical Center campus, it has backup generators so that it can be operated without traditional grid power. These generators are located above the highest floodplain levels to ensure their viability during Houston’s frequent floods. Currently, these backup generators are conventionally powered.

Data Sources & Reliability

Simulation software
VisualDOE (DOE-2.1 En136)

Green Strategies

• Daylighting for Energy Efficiency
  • Use building elements to redirect daylight and control glare
  • Locate floor openings under top-lighting to increase daylighting penetration
• Non-Solar Cooling Loads
  • Use operable windows
• Cooling Systems
  • Commission the HVAC system
• Photovoltaics
  • Design roof surfaces to accommodate future PV installations
• Ventilation Systems
  • Use heat-recovery ventilation
• Lighting Controls
  • Use occupancy sensors
• HVAC Distribution Systems
  • Consider using an access floor system
  • Increase area/specify low-face-velocity filters

previous topic: Site/Water

next topic: Materials

Our thanks to the ENERGY STAR program of the U.S. Environmental Protection Agency, and to the U.S. Department of Energy, and to BuildingGreen, Inc. for hosting the submission and judging forms.

For more information about the AIA/COTE Top Ten Green Projects, contact AIA/COTE. For help on how to use this Web site, contact .