David and Lucile Packard Foundation Headquarters

David and Lucile Packard Foundation Headquarters is located in Los Altos Northern California, on the south end of San Francisco Bay. Los Altos receives about 37 inches of rain annually, 263 sunny days per year. It has moderate temperature and humidity, the average high temperature in the summer is 78 degrees, and the average low temperature in the winter is 39 degrees .

David and Lucile Packard Foundation Headquarters is orientated 40 degrees off true north to fit in the urban fabric. The site orientation combined with multi-layering shading strategies made access to winter sun and avoid summer sun, at the same time allowed fresh air in the interior spaces through an operable façade. Instead of grouping the programs into one union block, the architect designed a center courtyard to bring sunlight and wind into more spaces.

Building on a previously developed, damaged, or polluted brownfield site, and designing the building so that it restores that site helps to mitigate previous environmental degradation.[2] David and Lucile Packard Foundation Headquarters set a good example for the reuse of brownfield. Before the development, the site was 97% impervious, covered in substandard, mostly unoccupied buildings and asphalt parking lots, and now it has reduced the imperviousness to 35% and the landscape is planted with local Californian vegetation. The design also took account the transportation needs in the community, the team developed a Transportation Demand Management Plan (TDMP) to not only reduce the demand for individual car parking but also offers alternatives for commuting.

The building has high standard insulation design, R-24 walls and roof and triple-element glazing (R-7.7). Occupants are able to adjust and control the environment by operating the windows and doors with a dashboard guidance showing when is the good timing to open and close windows depending on the outdoor temperature, wind speed, wind direction and relative humidity. The dimensions and angles of the shading devices were calculated from the locations of the sun in different seasons. The horizontal shading blocks the high summer sun and allows low winter sun to enter the interior of the building, and other devices are built into the design with elements such as trees, balconies, and trellis, which create a rich layering of lighting shades.

• 95% of materials from deconstruction were diverted from landfill
• Wood/steel hybrid structure, wood frame walls and all wood was FSC (Forest Stewardship Council)-certified
• Less embodied energy materials, such as 70% replacement-cement-for-slag concrete
• Material sourcing: wood veneer sourced from Eucalyptus trees felled during the Doyle Drive rebuilding project in San Francisco, California. Exterior wood is FSC-certified western red cedar. Stone is Mt. Moriah from the border of Utah and Nevada, within a 500-mile radius from the site. The exterior copper is 75% recycled, with a long life span and integral finish. Pineapples are a delicacy in Northern Guatemala

The accessibility of the sunlight is one of the key elements affect the positions and shapes of the building. Two 40-foot wide offices were placed apart to create a central zone for sunlight to enter from multiple facades in the building. The narrow plan allows sufficient daylight to reach deeper into the office spaces, and increase the daylight autonomy. Increase in daylight autonomy reduces 30% of the energy consumption from artificial lighting compared to a standard commercial building. The high transmittance of daylight in the winter (shading will block the direct sunlight in the summer) will also increase the heat gain and potentially reduce the demand for heating. Interior blinds are user-controlled to improve visual comfort, and it will rise automatically in the evening. The artificial light will dim or brighten up according to the change of daylighting.

The building is monitored by indoor sensors that send direct reminders to occupants to open the windows when natural ventilation mode is on.

Rainwater from the roof is routed to a 20,000-gallon underground cistern to meet 90% of toilet flushing and 60% of irrigation demand. The cistern overflows into a detention pond minimize storm water reaching the public storm system, and the storm water peak flow rates and volumes are reduced approximately 50% from pre-project levels.

In the winter, when the temperature drops to a certain degree, the building will be preheated to 23 °C (74 °F) in the early morning by the combination of air handlers and heat water beams in specific areas in the office spaces. And during the working hours, the heater will be turned off and the building heating will be fully relied on the internal heat gain from the computers, printers, and heat generated from the human bodies.

Heating demand is larger than cooling, as the summer temperature is pretty moderate in Los Altos. Water is stored and cooled in two 25,000 gallons underground tanks, and in the morning, it is pumped into the chilled beams to spread out to specific interior spaces. Besides chilled beams, there are three air handling units. Chilled beam system is designed with variable speed pumps and 130° angled pipes, which reduce the energy loss due to friction from the water flow compared to chilled beam system with typical angle pipes. This result is 75% reduction in ductwork and 75% reduction in pump energy, and the total cooling energy is reduced 90% from a typical chiller and VAV system.

Despite the orientation and slope of the roof is not customized for solar collection, the photovoltaic production most of the time covers 100% of the building consumption. In the first year of operation, the building was energy positive with a net energy use intensity (EUI) of −4 thousand British thermal units per square foot (−45 MJ/m²) per year, and total EUI of 22 thousand British thermal units per square foot (250 MJ/m²) per year.