By Larry Lessard and Michelle Harrison (G.E.T. staff)
The 2018 NY-GEO conference drew an international crowd of more than 300 people. The presentations and vendor exhibits were informative. A highlight of the conference was the fourth annual “GeoStar Top Job” competition, which included five finalists. NEGPA’s (New England Geothermal Professional Association) Vice President, Larry Lessard, of Achieve Renewable Energy in Salem, MA won the competition! The winning project was the conversion of a 19th century mill building in Arlington, MA to a 21st century technology incubator.
Arlington Center Garage and Service Corporation, the owners of the mill, were undertaking renovations of the timber and brick structure. The first floor was vacant, and Glance Networks, a technology company, occupied the second floor. The goal was to create a bright and inviting Class A office space on the first floor with multiple private offices and open work areas. This space was built for WorkBar, a regional, technology-focused workspace sharing company. Maintaining a short schedule to meet WorkBar’s move-in date was a key to project success.
A major part of the mill’s renovation was upgrading the HVAC system. The building was heated by a fuel oil-fired steam system which was replaced with a ground source heat pump (GSHP) system. Achieve Renewable Energy, LLC (Achieve) installed the GSHP. The GSHP system was chosen to meet the owner’s goal of reduced carbon emissions and lower operation costs.
There were permitting challenges for the project, as the project was within a wetland resource area. The available space for the ground source required crossing Mill Brook and a large sewer main. Achieve devised a method for pipe routing and obtained the required special permits.
The ground source consisted of eight vertical bores drilled in diorite and gabbro. Each boring was completed with a 1.25 inches diameter HDPE u-bend and backfilled with graphite-enhanced grout with a thermal conductivity of 1.6 Btu/hr-ft-°F. The borings were plumbed in parallel in pairs and combined in a pipe vault. From the vault, four inches diameter piping traversed the sewer main and brook.
Achieve installed variable-speed, central loop circulation that supported six WaterFurnace GSHPs. Three of the GSHPs utilize variable-speed compressors and condition up to six zones each. The other three GSHPs utilize two-stage compressors and support up to four zones each. The first floor design alone had 18 zones. The building has 24 zones. Each GSHP is monitored remotely using a WaterFurnace Aurora Web-Link (AWL).
Construction was completed on time, and the renovated facility opened to great fanfare. Based upon data from the AWLs, for the 12 months from March 2017 through February 2018, the approximately 12,000 sq. ft. historic building had total heating and cooling cost of $6,415 at $0.18/kWh. Of this, about $1,500 was cooling of a server room.
The mill owner commented that this is the lowest maintenance, quietest and lowest operating cost heating system at any of their numerous facilities. The GSHP system has been expanded as WorkBar expands. Achieve is now involved in a GSHP at the adjacent, larger mill building for the same owner.
Congratulation to Larry and his team at Achieve on their winning project!
Larry Lessard is the Vice President of NEGPA and Director of Achieve Renewable Energy, LLC.
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