The project, at Trinity's 50 Church Street property, will allow the building's atrium and roof to generate up to 66 kilowatts of solar photovoltaic energy while maintaining open views to the sky from the atrium area. The project also ensures far more effective year-round temperature control in the popular space, which provides additional meeting and work space for the office tenants and provides a venue for several community events and functions.
Designed by architects Bruner/Cott & Associates, the renovation at 50 Church resolved several longstanding challenges with the building simultaneously:
* Replacing a beloved but energy-inefficient glass ceiling over the atrium space that had been installed in 1980 and led to seasonal temperature extremes on the sunniest days of summer and darkest, coldest days of winter, which was at best akin to a "two-season porch"
* Ensuring Trinity could install a translucent solar array without being locked into a technology for the long term while solar PV output and technologies continues to grow-the solar panels are installed as a rain screen above, and separate from, the new atrium glass
* Replacing a failed passive-solar hot water system installed on a 55-degree tower on the roof over 40 years ago
* Allowing a modernization and renovation of a building in the heart of historic Harvard Square that was able to secure approval from the Cambridge Historic Commission.
"We've turned 50 Church Street into an even more attractive, comfortable, and now vastly greener and more sustainable building for all our tenants, visitors, and Trinity's company offices,'' said Trinity Property President John DiGiovanni, who is also president of the Harvard Square Business Association. "While we could have integrated solar modules to form a glass atrium ceiling, this innovative, collaborative solution enables us to capture all the benefits of the current generation of solar PV even as we maintain the flexibility to swap in even more efficient solar panels in future years without having to replace the atrium's glass ceiling."
The project uses translucent panels made by Lumos Solar of Colorado, which allow about 50 percent of sunlight to enter the atrium space for natural lighting and passive cold-season space heating while producing solar PV energy. About 10 kw of solar panels have been installed over the atrium glass, alongside another 56 kw installed on the room and tower structure atop the building. Combined, they can generate over the course of a year enough electricity to meet the needs of 10 average-sized Massachusetts homes and are offsetting a substantial portion of the total electricity consumption at 50 Church Street.
Haskell Werlin of Solar Design Associates, which served as the owner's engineer overseeing the project, said the project has yielded a number of real-world lessons about the most effective ways to install semi-translucent solar panels, including separating the array from the glazing by installing the modules as a rain screen mounted on custom rails suspended 9 inches above the glazing to allow for replacing them in case of breakage or damage without having to replace the actual roof glass.
Other members of the team working with Trinity Property Management, Bruner/Cott, and SDA on the project included project manager/general contractor Tom Clarke from Ashling Inc.; custom Atrium fabricator Linel; Atrium installed by W.S. Aiken Roofing; and solar installers KW Management and Boston Solar. Additional credit goes to Eric Grunebaum, a Cambridge based clean energy developer and impact investment broker/dealer with Bequia Impact who initiated the conversation several years ago with John DiGiovanni to encourage him to add solar PV to the building.