MSCA GreenSTAR University Mechanical Contractors Helps GSA Reach Top 1% in Energy Efficiency

By | 05/07/2014

Due to the dependability, expertise and timeliness of GreenSTAR contractor University Mechanical Contractors, Inc. (UMC), the Federal Center South Building 1202 (Seattle, Washington) has set a new standard in high-performance, cost-effective workplace environments. Aligned with the 2009 American Recovery and Reinvestment Act (ARRA) and the U.S. General Services Administration’s (GSA) Design Excellence Program, the Federal Center South Building 1202’s integrated design-build team developed a design and construction solution that synthesized active and passive systems, materials and strategies. With a design-build team consisting of UMC, ZGF Architects and Sellen Construction, UMC’s solution transformed the 4.6 acre brownfield site into a highly flexible and sustainable 209,000-square-foot (sf) regional headquarters for the Northwest Division of the U.S. Army Corps of Engineers (USACE).

To meet aggressive energy performance targets set forth by the GSA, the structure was required to meet the following minimum requirements:

  • Energy Use Intensity (EUI) of 26.8 kBtu/sf/year
  • Energy Star score of 97
  • Energy performance 30 percent better than ASHRAE 90.1 2007 standard
 

Intensive oversight, tireless testing and constant communication throughout the installation and commissioning phases brought the project to the finish line. But, it was the unique and proactive operations and maintenance approach that helped the project ultimately achieve the rigorous energy goals. This ignited a “light-bulb” moment for the design-build team: great projects have one thing in common - great partnerships.

POWERFUL PARTNERSHIPS

While the project was led by ZGF Architects and Sellen Construction, a local mechanical contractor trailblazer and GreenSTAR leader, UMC, was brought on to streamline the design process with their notoriously intricate design solutions. The highly collaborative design-build delivery and installation methods were the main drivers to meeting (and surpassing) the GSA’s performance requirements. These energy-conserving mechanical systems included:

  1. Chilled Sails: A chilled sail is a passive heating and cooling terminal device, similar to a chilled beam, suspended and exposed from the ceiling. The design-build team collaborated to customize the sails to achieve an aesthetic that would complement the building while still providing highly efficient cooling and heating capabilities.
     
  2. Under-Floor Air Distribution (UFAD) System: Due to the structure’s unique oxbow form, the design-build team installed a UFAD system with 100 percent outside air for ventilation, provided by four Dedicated Outdoor Air Supply (DOAS) units located on the roof. This system allows ventilated air to be distributed throughout the underfloor plenum via sheet metal airways and fabric ducts. The air then passes through the floor into the unit via floor-mounted displacement-type air diffusers—leading to improved thermal comfort, ventilation efficiency, and energy efficiency.
     
  3. Central Plant: The team installed a central plant that included two heat recovery chillers, pumps and a high-efficiency condensing boiler. These systems replaced conventional chillers and gas-fired boilers, and resulted in unsurpassable efficiency with simultaneous cooling and heating.
     
  4. Geothermal Energy Wells: The placement of geothermal energy wells extending 115 feet below-grade enabled the design-build team to leverage the earth’s heat as required by the building’s systems. Designed so that heat is rejected or accepted into the wells and balanced throughout the year to provide consistent heating or cooling as needed, the hours of operation for both the fluid cooler (for heat rejection) and the condensing boiler (for heat addition) are reduced significantly.
     
  5. Hydronic Heating: A decision was made to use water as a common heat transfer medium, allowing the separate and distinct systems to integrate, which dramatically increased the building’s energy efficiency. The hydronic heating system provides the majority of the heating for perimeter zones. Unlike the traditional electrical heating systems typically used in Pacific Northwest office buildings, the hydronic system increases overall system efficiency by recycling waste heat recovered from other systems.  


THE TOP ECHELON OF EFFICIENCY

While the complex mechanical systems in the Federal Center South Building 1202 are more advanced than those used in most office buildings, they may serve as a leading indicator for future projects. The key takeaway from the Federal Center South Building 1202 is that in order to optimize and fully realize the efficiency of highly complex and fully integrated mechanical systems, there must be a continuity of the knowledge that is developed by a project team.

The Federal Center South Building 1202’s current energy model exceeded the team’s initial goals. The building operates at 25.8 kBtu/sf/year—more than 30 percent better than the ASHRAE 90.1 2007 target. The Federal Center South 1202 will earn an Energy Star score of 100—placing this project in the top 1 percent of comparable buildings.
 

“This has been one of our smoothest, most successful projects because of the team we had.”
                                                                                                                   —Rick Thomas, GSA Project Manager  

For more information about this GreenSTAR case study or the MSCA GreenSTAR program, log-on to www.mscagreenstar.org or contact Barbara Dolim at bdolim@mcaa.org or 301-990-2210.

 

 

 

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