The Hewlett Foundation- LEED Gold

This energy storage system helps meet LEED standards by optimizing energy performance.  In fact, California’s stringent building code, Title 24, was exceeded by 35% as a result of the optimization.

Project Facts

  • First LEED Gold CERTIFIED building in California
  • Fifth LEED Gold CERTIFIED building in the United States
  • Five points in Energy & Atomosphere credit area
  • Title 24 exceeded by 35%
  • More project details
  • Take a Virtual Tour

First LEED Gold CERTIFIED building in California


LEED certification distinguishes building projects that have demonstrated a commitment to sustainability by meeting the highest performance standards.  These performance standards include criteria for sustainability, water efficiency, energy and atmosphere, materials and resources, indoor environmental quality, and innovative and design process.

So when the William and Flora Hewlett Foundation building was awarded the Gold certification, the first ever in California, its significance was not lost on the organization and its supporters.  

The Hewlett Foundation’s broad purpose, as stated in the articles of incorporation, is “to promote the well being of humanity by supporting selected activities of a charitable nature, as well as organizations or institutions engaged in such activities.”

“Thermal storage cooling reduces greenhouse emissions and uses less energy because it uses electricity, which is produced at night by the utilities’ most efficient generating plants,” said Igor Tartakovsk, Principal, P.E. of C & B Engineers

The Foundation concentrates its resources on activities in conflict resolution, education, environment, family and community development, performing arts, population, and U.S.-Latin American relations. Although The Hewlett Foundation is an international foundation, with no geographic limit stipulated in its charter, one subarea of interest is the non-profit National Commission on Energy Policy.  The Commission’s goal is to develop a long-term U.S. energy strategy that promotes national security, economic prosperity, and environmental safety and health.

The Hewlett Foundation has a solid commitment to the voluntary, nonprofit sector and therefore assists efforts to improve the financial base and efficiency of organizations and institutions in this category.  With such a strong commitment to beneficence, it stands to reason that the Hewlett Foundation would be equally concerned about the environment when building its new building in Menlo Park, California.

“Our hope for the building is that it will both inspire our work and contribute to increased interest in environmental technologies” stated Paul Brest, the Foundation’s president.  So vital was their commitment to green concerns that the Foundation even created an informational tour fact-sheet on their building’s environmental friendliness and titled it “Environmental Values at Work”.  


The building’s environmental and ecological concerns were addressed both in its physical, lighting, mechanical and air-conditioning systems.  

Physical Considerations

Physical aspects of the Hewlett buildings’ environmental concerns include:
•    use of materials containing a level of recycled content
•    use of wood from forests certified by the Forest Stewardship Council
•    use of light colored, non-petroleum based paving material on parking lots and pathways, which help to keep surfaces 20% cooler than asphalt.

Even the building’s location was selected partly because it is served by three bus lines within a ¼ mile, linking the building to a railroad station.

Lighting Considerations

Relying on a combination of indirect natural light over central workstations and light wells, the building’s three floors received natural daylight throughout the day.  A photovoltaic roof panel was used to supply power for mandatory, 24 hour exit lighting. Even the garage was partially lit by allowing natural light to enter.

Mechanical Considerations

“The planning stages for the building took place at the height of the California energy crisis,” noted Jo Carol Conover, a principal of Benning & Conover and the building’s Project Manager.  “Since the cost of California energy and its availability were at a premium, the Hewlett Foundation put great emphasis on both its cost reduction and conservation.”

Steps taken by the building planners included installing controlled, operable windows that allow the building to vent naturally as well as by its occupants.  “The under-floor air supply helps to reduce air required at each office,” adds Mrs. Conover.  “That, in combination with the efficient air-conditioning system contributed to the building’s favorable energy rating.”


In order to prove that employee comfort needn’t be sacrificed in a building designed to maximize the efficient use of available resources, it was decided to incorporate Thermal Energy Storage technology into the building plan.  This technology was chosen as a key component of the building’s cooling strategy as it enabled the project planners to assure the organization that energy costs would be held to a minimum.

Igor Tartakovsky, Principal, P.E. of C & B Engineers and the project’s Mechanical Engineer said “we considered photovoltaic cooling as an option, but after running the numbers, it turned out to be too expensive.”

The energy storage system help meet LEED standards by optimizing energy performance.  In fact, California’s stringent building code, Title 24, was exceeded by 35% as a result of the optimization.  Accordingly, the USGBC website states that thermal energy storage technology was part of the strategy used to earn five points in the Energy & Atmosphere credit area of the LEED rating system.  

The thermal energy storage operating principle does not rely on chillers to operate during “peak demand” periods.  “Peak demand” periods are those times during the day when energy use is highest and therefore energy cost is also higher.  Instead, chillers are used during nighttime, “off-peak” periods to form ice inside a series of six 8ft high tanks.

“The entire specification and installation process for the IceBank tanks went very smoothly. The tanks arrived on time and were operational within a week,” said Jo Carol Conover, a principal of Benning & Conover.

According to James Poole, PE, Trane’s Applied Marketing / Global Account Manager for the San Francisco Bay Area, “Thermal storage also allowed for downsizing the chiller plant, avoiding grid connection charges as well as significantly reducing operating costs.”

When the local Pacific Gas & Electric utility generating plant enters the “peak demand” period, the energy storage system calls for the chillers to be turned off.  The higher priced daytime energy is then used merely to circulate anti-freeze solution through the ice that had been formed in the tanks at night, and into the building’s air-conditioning system.  Since the evaporatively cooled chillers will not operate during peak demand periods, the energy load will be shifted from high peak usage periods to low usage periods.

“The ‘green’ benefit of energy storage is realized in that it reduces the need for additional generating capacity, an important issue in California,” added Mr. Poole.  

Thermal energy storage advocates promote the fact that for every four buildings cooled by this technology, a fifth building can be cooled without the need for additional generating capacity.  Furthermore, greenhouse gas emissions are reduced because nighttime energy is produced more efficiently.

“Thermal storage cooling reduces greenhouse emissions and uses less energy” claims Mr. Tartakovsk, “because it uses electricity, which is produced at night by the utilities’ most efficient generating plants.”


“The entire specification and installation process for the IceBank tanks went very smoothly,” Ms. Conover said.  “The tanks arrived on time and were operational within a week.”

Currently the building is completely cooled using the CALMAC tanks.  “However,” notes Igor Tartakovsky, “should additional cooling be required, the installed chillers could be used to supplement the system on a temporary basis.”


The Williams and Flora Hewlett Foundation now stands as a model for future ‘green’ efforts, a view which is supported by Contractor and Senior Project Manager Kailasam Senthil of Critchfield Mechanical Incorporated.  Mr. Senthil states,  “With the awareness raised by the recent energy crisis these systems are going to become more popular.  It isn’t just the fashionable thing to do; it is a real solution to a very real problem.”

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