Chestertown project meets Living Building Challenge
The challenge was to create a highly sustainable college classroom and laboratory building on the water’s edge. The solution for Washington College and the project team for the Semans Griswold Environmental Hall project was to embrace the Living Building Challenge.
Described as the most advanced protocol for sustainability in design and construction today, the Living Building Challenge aims to produce facilities that positively impact the environment. Design and construction teams must create buildings that generate more energy than they use, capture and treat all water on site, and utilize healthy construction materials. They must also demonstrate that the completed, occupied building continues to meet those goals through ongoing monitoring.
Although Gipe Associates Inc. had completed other projects at Washington College and a few net zero projects, Semans Griswold Environmental Hall would be its first Living Building Challenge.
“The biggest challenge with a project like this is getting the energy load of the building down to an absolute minimum so that the PV system for the building is affordable,” said David Hoffman, President of Gipe Associates, which provided mechanical, electrical, plumbing and fire protection systems design for the project. “The first step — and I think this is absolutely necessary in any building that is trying to reach net zero — is a geothermal system. Geothermal is light years ahead of conventional systems because of the way the compression cycle works.”
In addition to a high-performance, closed loop geothermal system, Gipe included multiple other energy efficient systems in the design for the 11,000-square-foot building. Those included ductless heat pumps as peaking units, electro-commutating motors (ECMs) for water source and heat pump units, variable speed compressor/fan strategies, variable speed pumping, energy recovery wheels and heat pipe energy recovery, exhaust air energy recovery equipment, low-flow water fixtures, and LED lighting and controls.
Gipe worked with the college to establish schedules and set points for HVAC systems so that the building could achieve the modeled energy performance. It also included separate meters for plug loads throughout the building.
Achieving net zero in a building with three laboratories, however, also required some “out-of-the-box” design elements, Hoffman said.
Gipe employed an old-fashioned, energy efficient method of ventilation — namely, operable windows — but modernized the design with interlocked controls to the HVAC system. When an occupant opens a window, the controls de-energize the heat pump for that zone of the building. To prevent occupant actions from negatively impacting the energy efficiency of the building, temperature sensors will trigger an alarm if a window is left open and part of the building becomes too hot or too cold.
Gipe also included a demand-controlled ventilation system in the building’s design. It monitors carbon dioxide levels throughout the building and adjusts the ventilation accordingly.
“Carbon dioxide is a surrogate indicator for how many people are in the space,” Hoffman said. “If there are few people inside, why pump all that code-required ventilation into the room? That feature produces substantial energy savings.”
The final design for Semans Griswold, which includes a solar PV installation, concluded the building would meet the Living Building Challenge requirement of producing at least 105 percent of the energy it will use. Building monitoring since last September has shown the facility is exceeding that goal. The building may not have been fully occupied over the winter due to the pandemic. However, Hoffman expects the facility could readily and comfortably support a full complement of students and staff. “I don’t think this building is restrictive in any way that users or students would notice.”
Although the Semans Griswold project came in under budget ($11.4 million compared to the budget of $12.5 million), Hoffman notes that these types of buildings are not inexpensive and can exceed the cost of a LEED Platinum facility. One contributor to the cost is the Living Building Challenge requirement that buildings use batteries, rather than generators, for backup power. “I think that’s a mistake because you are connected to the utility which is a free battery,” he said. “It is very costly to install batteries, maintain them and replace them every eight to 10 years.”