WSP USA is C.R.E.A.M. of the Crop at Net-Zero Competition

Net-zero energy efficiency is a desirable goal for modern buildings, but a team of WSP USA designers recently demonstrated the potential for creating practical building systems that expand this vision even further.

The team, calling themselves Carbon Rules Everything Around Me (C.R.E.A.M.), outperformed challengers representing engineering firms, universities, and other professional service companies from across the U.S. and Hong Kong to win the LowDown Showdown, an annual energy modelling competition sponsored by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).

The months-long competition gives engineers an opportunity to showcase their design and modeling skills by developing highly sustainable and innovative projects that could shape the future of energy efficient buildings.

This year’s challenge? Design a new 90,000-square-foot city hall building for San Diego.

“What set our entry apart was our ability to incorporate a low environmental impact with an inspiring design that resonated with the judges and the public,” said Elliot Glassman from the New York office, who led the architectural design. “We generated a building that anyone would be happy to work in given the access to daylight, warmth of the materials, and the copious amounts of vegetation incorporated.”

Historically, the competition criteria focused on reducing building energy usage, with teams shooting for net-zero energy consumption. But this year, the competition expanded its focus to include resiliency and occupant health and wellness elements, which had a significant impact on the scope of the competition.

The winner was announced at ASHRAE’s 2019 Building Performing Analysis Conference in Denver in late September, where the top five teams in the competition were invited to present their designs.

C.R.E.A.M. envisioned its new San Diego City Hall as a hub for local governance that would also serve act as the area’s Emergency Operation Center. They also saw an opportunity to take the design a step beyond the expected.

“We exceeded the competition requirements by producing a net-positive energy building,” said Kristy Kwong from the Los Angeles office, who worked on environmental analysis and resiliency. “This meant that this building design would produce more energy annually then it would consume.”

To meet this goal, they used passive design elements to reduce cooling and heating loads. The building was shaped so that it would self-shade, while keeping the floor plates narrow to allow ample daylight and natural ventilation.

Once the loads had been reduced, the model met its efficiency goals through a modular heating-ventilation-air conditioning (HVAC) system. Finally, the project was topped by a photovoltaic (PV) array spanning the central courtyard that also acted as a shading trellis for the building and outdoor spaces.

“The PV array would provide enough power for net-positive energy during normal operation, while enabling the building to serve the community during natural disasters,” said Jason Lackie, a building performance specialist in the Tempe, Arizona office and the WSP team captain. “In addition to being an exemplar of resiliency, the design provides abundant planted outdoor spaces on all floors to increase the occupants’ connection to nature, thereby improving health and wellness.”

The use of mass timber and cross-laminated timber construction provided additional natural elements while reducing embedded carbon.

“Wood has much less embodied carbon than steel and concrete, and we wanted to reduce all carbon associated with our design, not just operational carbon,” said Mohammad Abbasi from the Chicago office, who lead the team’s efforts on incorporating occupant comfort and wellness into the project. “Also, wood elements have a natural warmth to them, and we wanted to incorporate as much biophilic elements as possible.”

The team used Grasshopper computer-aided design tools for most of the modeling, allowing them to integrate the design exploration process with multiple types of analysis within the same digital environment, increasing efficiency of the modeling process and more strongly embedding performance into the architectural design.

For example, the HVAC team first defined a model of the mechanical system and operations options, then tested the result using a simplified parametric façade analysis, a method that helps define the relationship between a design’s intent and its actual response.

“Passive design features are generally good strategies we advocate for on all projects, but how they manifest on a specific project depends on the particularities of climate, site, building form and type of program use,” added Glassman, who also served as the team’s lead developer for the parametric tools used in the competition. “We parametrically model each project within the design intention to find the right balance of heat flows, given the internal loads and external environmental influences.”

C.R.E.A.M. investigated some alternate refrigerant blends that are still emerging in the market place, recognizing the potential benefit of using refrigerants with lower global warming potential (GWP). They seized this opportunity to explore their application and start spreading the word.

“We successfully developed our customized HVAC system and heat recovery chiller with the new low GWP refrigerant HFO-1234ze,” said Zach Stevens from the Seattle office, the team’s carbon specialist who pioneered the team’s investigation into the use of low GWP refrigerant blends. “It took a long time to test the script and make sure the energy results made sense.”

The final project not only met the competition’s energy, resiliency, and health and wellness requirements, but also achieved the team’s self-imposed performance goals for aggressively saving water, reducing the structural system’s embodied carbon, and using the lowest possible GWP refrigerant.

“The judging committee appreciated the thought that went into those extra considerations,” said Xinxin Hu from the San Francisco office, who worked on envelope and daylighting design. “They also commented on the strength of our teamwork, based on how knowledgeable each of us spoke about multiple project aspects during our presentation.”

When C.R.E.A.M. was announced as the champion, Lackie was elated that their hard work and attention to detail had paid off. He was “stunned” when it was announced that their design also won Fan Favorite, receiving more than half of the total votes at the convention.

The competition gave each team member a chance to contribute ideas, research and sweat equity to an innovative concept. Despite disparate geography, experience levels and areas of expertise, their unified purpose and passion was unquestionable.

The C.R.E.A.M. team was a cross-country collective that also included Audrey Ng from the Boston office, who analyzed site conditions and developed the project’s approach to water conservation; and Joelle Jahn, an architect from the Boston office; with assistance from interns Claudia Mezey, Aneri Shah and Jack Rusk in New York City.

Team coaches also played a critical role as active partners in collaborating across disciplines. Konstantin Udilovich in New York City consulted on seismic implications to the project’s structural design and on optimizing the structure for embodied carbon studies. Chad Spencer in Tempe consulted on the development of the modular chiller plant, electrical storage systems, and the use of low GWP refrigerant blends.

When the competition kicked off in April, the WSP team faced logistical and scheduling challenges, particularly with the coordination of design efforts across seven offices in three time zones.

“Because of these constraints, we opted to differ from a traditional, critical path approach where delays in individual analysis would hamper the overall team progress for a parallel path process,” Lackie said.

Although the team had nearly six months to work on this project, and most work was done outside normal work hours. Despite each team member’s demanding project commitments, they overcame their geographic challenges and found time to collaborate.

“We knew there was no guarantee of success, especially after seeing some of other teams’ innovative ideas,” Ng said. “We also knew our ideas were strong, and that it was worth devoting long hours to create the best possible design.”

Team C.R.E.A.M. believes that good design and good performance are necessary goals for any successful project, and were factors in the team’s victory.

“The way to achieve this dual objective is through an iterative design process that assesses multiple options for each decision and integrates multiple performance considerations into each design gesture,” Lackie said on behalf of the team. “This competition was an opportunity to validate our approach and put the analysis tools we have developed over the course of our work to the test.”

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