WORCESTER — When the new $316 million Doherty Memorial High School is expected to be finished in two years, the building's overall energy efficiency will be a “huge step forward,” said John Odell, the city’s chief sustainability officer.
Doherty’s design tops energy-efficient standards in the state’s current building code by 35.7%, Odell said.
The design’s original goal was to exceed the mark by 20%. Currently, the state code for new construction doesn't require net zero.
That term means the amount of carbon dioxide that enters the atmosphere — a major contributor to climate change — is offset by an equal amount of CO² pulled from the air.
There are several reasons why city officials believe the 35.7% mark will be reached. One is the new school's primary source of heat will come from electricity, not fossil fuels.
Insulated walls and ceilings, fiberglass frame efficient windows and energy-efficient lighting are other contributors.
Bases on its energy features, the building meets the LEED (Leadership in Energy and Environmental Design) silver standard.
Not free of fossil fuels
Fossil fuels will supply the school's heat, in certain situations.
High-energy gas-powered boilers will be used for backup heat, but only during extremely cold days or a prolonged power outage so the building can be used as a warming shelter.
Roughly 99% of the school’s heat will come from two electrical systems that are heat pumps and variable refrigerant flow, Odell said.
Heat pumps work this way: In summer, it’s like a regular air conditioner, taking warm air from inside and moving it outside.
The reverse happens in winter as the pump takes warmth from outside and brings the heat into the building.
VRF uses heat pumps to provide heating and cooling for all indoor units without the use of air ducts.
The new school will have rooftop solar panels, and when they're in place, the building will be carbon negative, Odell said. That means removing more carbon than the amount emitted.
Solar panels will be in place when the building opens or within one year after completion, Odell said, and will generate enough electricity to equal the amount used by 338 homes in Worcester annually.
Trees cut down
Trees were cut down to make room for the new school, and Odell said he didn’t have the number immediately available. More will be removed when the old Doherty is torn down to make way for a parking lot and athletic field.
At least 75% of materials demolished from the old building will be recycled or reused, said Odell.
Odell pointed out that the trees removed were largely invasive species. While they helped the environment by pulling carbon out of the air, native species will be planted in their place that live longer and absorb even more carbon.
Plus, since the new trees will live longer, creating bigger tree canopies, there will be more shade to provide relief on extremely hot days.
Stand the test of time
When asked if the new school's energy-efficient systems will remain effective over the long run, especially in an industry that experiences rapid changes in technology, Odell, said, "It will stand the test of time.
“This is not bleeding-edge technology,” Odell said. "This equipment and technology is used in a lot of buildings. It's proven reliant and durable. We’re putting in the most efficient systems we can right now.
“Eventually when they’re replaced in 20 years, we’ll upgrade with the most efficient systems available at that time.”
The new school’s original price tag was $293 million. The city council approved an additional $23 million borrowing in May to cover cost overruns.
Contact Henry Schwan at firstname.lastname@example.org. Follow him on Twitter @henrytelegram
This article originally appeared on Telegram & Gazette: New Doherty Memorial High School in Worcester design tops state's energy-efficient standards