LEED® Platinum: Incorporating a Powerful Metaphor

Dedicated to fighting world poverty and hunger, Mercy Corps International (Mercy Corps) is a team of 3,700 engineers, financial analysts, community organizers, project managers, public health experts, administrators, entrepreneurs and logisticians who daily help turn crisis into opportunity for millions of oppressed individuals around the world. A global humanitarian organization, Mercy Corps has been headquartered in Portland for nearly 30 years.

Move to Historic Neighborhood – Redesign, Restore 118-Year-Old Landmark

On Sunday, September 24, 2006, The Associated Press reported, “Mercy Corps, the Portland-based global humanitarian organization, will soon break ground on a $35 million headquarters in the downtown Chinatown neighborhood that’s been targeted for redevelopment.” Mercy Corps had outgrown its six leased headquarters buildings and purchased the historic, 42,000-square-foot Packer-Scott building – built in 1892 – to house its growing staff of unique professionals.

Early in 2006, Mercy Corps sat down with its Portland, Ore. design partners – Thomas Hacker Architects, Inc. and Glumac Engineering, Inc. – to forge plans for its new headquarters building. This consisted of renovating half of the existing historic building and a new construction addition resulting in a combined space of 82,000 square feet. This endeavor would bring all Mercy Corps employees together in a single location.

The project team wanted the new facility to be designed in a spirit consistent with the worldwide mission, sensitivity and sustainable practices at the core of the international aid organization. The 1892 Packer-Scott Building would be restored to its original form to serve as a record of its time and would be upgraded to blend seamlessly with the contemporary structure newly joined.

Striving for LEED Platinum: Focus on Energy Performance

“Originally we aimed for a LEED Gold or Platinum rating, but soon discovered we were meeting the platinum certification levels and needed a new metric for our lofty goals,” remarked Rob Schnare, project engineer, Glumac Engineering, Inc., Portland, Ore. The Living Building Challenge (U.S. Green Building Council’s Cascadia Chapter development) provided this new metric.

Because of the sustainable design, green building materials and great site location, Schnare said the team’s goals for achieving a LEED Platinum rating focused a lot on energy performance. He said the standard used for energy performance analysis is the Performance Rating Method (PRM) as defined in Appendix G of ASHRAE 90.1-2004. The design incorporated many energy efficiency measures (EEMs) that were analyzed throughout the design process, including a Variable Refrigerant Flow HVAC system, 100 percent Dedicated Outside Air system, carbon dioxide sensors, daylighting, improved envelope insulation, energy efficient windows and an 80 kW future photovoltaic (PV) array.

Since the Mercy Corps headquarters is a partial existing building renovation and partial new construction, Schnare explained that the New Construction and Existing Building point thresholds for each energy and atmosphere credit are averaged to give the new point thresholds for this specific project. Each point threshold is adjusted to 3.6 percentage points less than the New Construction thresholds (e.g. the first point starts at 6.9 instead of 10.5 percent).

Using LEED and ASHRAE 90.1 rules, Schnare outlined the energy cost saving goals for the building. Without renewables, he calculated the budget baseline to be $37,600 per year or 35 percent. With the addition of an 80 kW PV array, the building should save an additional $5,000, increasing the total energy cost savings to $42,000 or 40 percent. Overall, the building was designed to save 136 tons of CO2 annually over the ASHRAE baseline.

Maximizing Energy Performance: Selecting a VRF System

Schnare said the project team knew that to reach LEED Platinum they had to find a highly efficient and energy-saving HVAC system. The team considered many options including packaged gas/electric rooftop Variable Air Volume (VAV) systems, low temperature central VAV systems and Variable Refrigerant Flow (VRF) zoning systems.

It was Glumac Principal James Thomas who recommended the VRF zoning system from Mitsubishi Electric Cooling and Heating Solutions, Suwanee, Ga. Thomas and Schnare identified the following benefits from the Mitsubishi Electric technology that would help Mercy Corps achieve Platinum: packaged zone design simplifies application; fan coils are extremely quiet; fan coils and refrigerant piping are adaptable to limited ceiling height or exposed structure; console units are available for wall mounting or horizontal fan coils for concealed locations; extremely adaptable fresh air ventilation system permits adaptive control of indoor air quality based on occupancy and demand while minimizing energy use; moderate relative first cost; design is flexible —new zones can be added easily; packaged zone controls for fan coils provide high relative control value; and finally high partial load heat pump efficiency.

Mitsubishi Electric VRF System Receives 100 Percent of Energy and Atmosphere LEED Credits

The project team decided to go with the Mitsubishi Electric system. Thomas Hacker Architects designed the addition. Renovation started in the Packer-Scott Building in the summer of 2006. Groundbreaking for the new addition took place in September of that year. As the new Mitsubishi Electric VRF system was to be installed throughout the entire 82,000 square feet, all existing HVAC equipment servicing the landmark building was removed.

“The USGBC gave us 10 points in the Energy and Atmosphere credit,” Schnare said. “This EAc4 credit limits the amount of refrigerant used on a per ton basis. With the inclusion of the dedicated outside air system, the overall building refrigerant was limited to meet this credit requirement with zero use of CFC based refrigerants. It allowed the building to easily split into five different tenant zones that aided EAc5 measurement and verification. Combined with a dedicated outside air system (DOAS), we were able to achieve Environmental Quality credit 1 (EQc1) where the building ventilation air is monitored and controlled.

Other Sustainable Design Highlights

LEED Platinum credits were also awarded because the project team reused 75 percent of the existing Packer-Scott Building; 75 percent of the construction waste was recycled; 7.5 percent on-site renewable power was generated through a PV array; a green roof was constructed and bioswales treated stormwater runoff; and high energy-efficient building systems achieved 51.8 percent above code baseline. The future PV array structural system will be installed above the green roof for more proficient performance.

HVAC System Performing Well: Easy to Manage

Administration and Facility Manager Steve Zodrow joined Mercy Corps in February 2009. “The headquarters was occupied in mid-September, 2009,” Zodrow said. “Although we have not been through the hottest part of the year, the Mitsubishi Electric VRF zoning system has been operating smoothly. I have had very few complaints from building occupants and the few adjustments that we have made have been effective. Our team is extremely pleased with temperature and air flow resulting in a very comfortable work environment. And most importantly, the HVAC system has been a lot easier to manage than I had imagined.”