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Keeping Sherman Green

When it opened in January of 2013, the Albert Sherman Center (ASC) was the greenest building on campus, achieving LEED Gold certification from the U.S. Green Building Council. Living up to that standard, for the benefit of the environment and cost savings, remains an ongoing challenge.

Some of the challenges faced and solutions developed by the UMass Chan facilities team to improve efficiency at the ASC were presented on March 15, 2016 at the Green Labs Symposium sponsored by the Boston Green Ribbon Commission and hosted by Harvard University. 

“This is the second year we were invited to present at this conference, which I think is important because these green lab buildings are extremely complex and by sharing our experiences, and hearing from others who face similar challenges, we are able to advance best practices and have a broader impact,” said Suzanne Wood, sustainability and energy manager at UMass Chan, who is also a LEED Green Associate.

While they have great potential, driven by innovative design and advanced technologies, so-called “green buildings” can fall out of balance and consume more energy than expected. Furthermore, sometimes the early application of advanced building technology does not produce the complete savings expected, so the systems may need to be modified.

After monitoring the actual energy consumption at the Sherman Center for several months post-occupancy, the facilities team found the building was using more chilled water and steam than predicted. “What we are learning is that the energy modeling used in the design phase doesn’t always match the actual operation of the building,”  said David MacNeil, PE, senior mechanical project manager at UMass Chan.

MacNeil and the school’s building commissioning consultant studied operational data generated by the Sherman Center’s energy management system. That analysis exposed several operational issues that were wasting energy, chief among them was simultaneous heating and cooling of air being delivered to occupied spaces.

At issue were the heat recovery wheels built into the HVAC system as an energy efficiency feature. When working properly, the massive rotating wheels allow the system to exhaust stale air and draw in fresh air while retaining most of the heat in the building.  That saves a lot of energy when it’s cold outside, but it turned out that in warm weather the wheels did not come to a complete stop. Because they continued rotating, albeit slowly, the wheels heated already warm fresh air to the point where the building’s air cooling system had to chill it down before delivering the air to offices and labs.

“Simultaneous heating and cooling is not something occupants would notice,” MacNeil said. “As long as people are comfortable, and not hearing excessive noise from the mechanical systems, then they don’t realize anything is wrong.”

MacNeil said there was no clear reason why the wheels remained in motion, so the control system was adjusted so that the wheels now come to a complete stop when appropriate. Also, the temperature set-points for when the wheels start and stop were broadened by several degrees.

Another major improvement was realized when the amount of air flowing through the office areas of the building was reduced by approximately one-third. “There was no impact on comfort or air quality,” MacNeil said. “When I looked at the data, it was clear that we were exchanging too much air, well beyond what we needed to.”

UMass Chan facilities management and the engineering team continue to monitor ASC operations and will implement additional energy conservation measures (ECMs) as they are identified through fault diagnostic software installed in the building. They are currently studying the occupancy/vacancy sensors in several areas of the building to see if they can be used more effectively. Steam usage and the accuracy of the steam meters in the building are also under review. “Overall, the Sherman Center is still a very efficient building,” MacNeil said. “And we are moving in the right direction to achieve more savings.”

In addition to the energy efficient systems, the Sherman Center was certified LEED Gold for several measures, including the use of recycled steel at its core, wood finishes harvested from certified sustainable forests; carpets and textiles made from recycled fibers; and low-flow plumbing fixtures used in most areas. Rainwater from the roof and condensate water from the heating and cooling systems is captured and reused by the campus power plant, saving hundreds of thousands of gallons of fresh water each year.

The orientation of the Sherman Center, and the exterior materials used, contribute significantly to the building’s efficiency. On the north side of the building, where the laboratories are located, the façade is mostly glass, with long windows designed to allow in as much natural light as possible. On the south side of the building, the windows have external baffles, or sun-shades, designed to block much of the heat energy of the sun’s rays and to bounce some of the light up to the interior ceilings of the offices and educational spaces. The glass on the south side is also slightly more reflective than the rest of the building to further minimize solar glare and heat gain. The building’s roof is white and gray, and the exterior terracotta lightly colored, so the surfaces reflect rather that absorb heat. The result is an exterior envelope that helps reduce the need for electric lighting, heating and cooling of the facility.