HVAC Improvements and Solar Photovoltaic Systems


HVAC Improvements and Solar Photovoltaic Systems

Greater Lawrence Sanitary District


About this Project

FST completed two assignments for the Greater Lawrence Sanitary District (GLSD), located in North Andover, MA. The first involved design and construction phase services for HVAC improvements at the District's WWTF and Riverside Pump Station, including replacement of a constant speed drive with a variable frequency drive, ventilation system improvements, installing a new energy efficient temperature control system, and addition of two new energy-efficient boilers with dual-fuel burners capable of burning both digester gas and natural gas. Burning digester gas for building heating and hot water makes use of an energy resource produced onsite, while also reducing dependence on fossil fuels. There is also a decrease in greenhouse gas emissions at the WWTF because the excess digester gas is now used for heating and hot water instead of being flared off.

FST's second assignment for GLSD was a design-build project for the addition of solar photovoltaic systems - both ground-mounted and roof-mounted. FST worked with a solar subconsultant to evaluate and perform preliminary design of eight roofs and two land areas as potential sites for solar arrays. The project's contractor chose to complete design and construction at the two land areas, for a total capacity of about 441 kW. Specific design services included solar resource measurement, evaluation of electrical distribution system for optimal interconnection point, evaluation of roofs for structural integrity, wetlands permitting, and preparation of 20% design and performance specifications for a turnkey installation of a grid-tied PV system. FST and its subconsultant also assisted with an extensive evaluation of bids submitted in accordance with Massachusetts General Laws, Chapter 25A, Section 11C. Construction phase services included design and shop drawing review, periodic inspections, and preparation of a PV system performance commissioning report.


More Information

Owner: Greater Lawrence Sanitary District (GLSD)

Location: North Andover, Massachusetts

Highlights: Both projects received funding from the American Resource and Recovery Act (ARRA), and were on tight schedules for design, bid and award.