METROPOLIS has announced that a team of young architects and engineers from HOK and Vanderweil Engineers has won the magazine’s Next Generation Design Competition with a proposal for a visionary, net-zero retrofit of a 1960s federal building in Los Angeles. The Washington, D.C.-based team, which worked on a volunteer basis for three months to create the winning submittal, offered a fully integrated design solution highlighted by solar collection, photovoltaic (PV) production, and the breakthrough use of an on-site microalgae bioreactor system.

The HOK/Vanderweil team’s proposal, “Process Zero: Retrofit Resolution” demonstrates how an aging downtown office building, owned by the U.S. General Services Administration (GSA), could yield an 84% reduction in overall energy demand through energy conservation and renewal strategies. On-site energy generation would supply the remaining 16% needed to achieve the net zero goal.

The team’s recommendation of the use of an energy-producing envelope system — highlighted by a modular system of algae tubes along the building’s façade — was among the many strategies that appealed to the Next Generation jury. The tubes would absorb the sun’s radiation to produce lipids for on-site fuel production, while also shading interior office spaces within the 1.2 million square-foot building. The 25,000-square-foot microalgae bioreactor system would generate 9% of the building’s power supply following the retrofit.

“Harvesting algae to generate energy is a new concept for building applications, but it shows a lot of promise,” says Brandon Harwick, P.E., who led the design team along with HOK’s Sean Quinn. “Urban buildings would be especially suitable given the carbon dioxide levels found in city environments. As design professionals, we need to remember that nature has a lot to offer.”

The 15-person team “put in a lot of weekends and long nights” says Harwick. “It was many hours of research, design, and number crunching, but we also tried to be as creative as possible and bring a lot of ideas to the table. We wanted to demonstrate an approach that not only reflects the latest in design and technology, but calls for a whole new mindset — one that engages and involves tenants as well.”

Highlights of the retrofit proposal include:

  • Thin film PV façade solar shading system
  • Rooftop PV panels
  • Integrated solar-thermal and PV rooftop panels for space and domestic water heating
  • An algae bioreactor system
  • A cloud computing system contributes to an 80% reduction in office equipment energy use
  • Radiant floor heating
  • Geothermal cooling
  • Rainwater harvesting
  • Energy recovery mechanical ventilation
  • Central atria for daylighting and natural ventilization
  • Phase-changing insulation material in ceilings to help extend natural ventilation periods
  • Daylight controls reduce artificial lighting energy consumption by 75%
“What is particularly remarkable about this solution was how a large, interdisciplinary team collaborated on a comprehensive plan that not only achieves net zero, but also deploys its design and technical solutions in a humanistic and contextually integrated way,” says METROPOLIS Editor-in-Chief Susan S. Szenasy.

GSA Chief Architect Leslie Shepherd says he and the other jurors were impressed by “the sophistication of the winning entry, and of the many other inventive submissions. With appropriate testing and validation, certain Next Generation strategies could be replicated across a wider swath of our Great Society-era buildings.”

The winning proposal was featured in the May 2011 issue of METROPOLIS.