San Francisco Public Utilities Commission (SFPUC) headquarters

Providing the HVAC system for North America’s greenest building

Opening in July 2012, the San Francisco Public Utilities Commission (SFPUC) headquarters in downtown San Francisco at 525 Golden Gate, has been called “the greenest office building in North America”. Compared to similar 13-story office buildings, 525 Golden Gate produces 50% less of a carbon footprint, uses 32% less energy, and 60% less water.

NSW worked closely with SJ Engineers of San Francisco, California and ACCO Engineering Systems in San Leandro, California to ensure all the requirements were met on this complex project.

Selecting Chillers for More Than Just Performance

Daikin Magnitude Chiller

Two Daikin Magnitude chillers were selected. One 500-ton and one 250-ton unit with magnetic-bearing oilless compressors and integral variable frequency drives. These chillers are 40 percent more energy efficient than traditional centrifugal compressor chillers. On top of that, their compact footprint, weight, and electrical service made them the perfect choice for the project.

The building’s HVAC system design is based on a traditional four-pipe system and includes the two chillers, two rooftop cooling towers for the chilled water system, two large variable air volume (VAV) custom air handling units, heat exchangers, and an underfloor air-distribution (UFAD) system.

The building’s UFAD system, also provided by NSW, accommodates data lines and most of the ventilation infrastructure, including air handling equipment, as well as linear and swirl diffusers in the floor supply air for cooling. This system serves to reduce heating, cooling, and ventilation costs by more than 50%.

With all the efficiency measures, the building’s design exceeded ASHRAE 90.1 requirements for energy efficiency for heating and cooling in new office buildings by an impressive 51%, earning it the moniker of greenest building in North America.