Located in Williamstown, MA, the Highland Woods Senior Housing project is a 40-unit apartment complex designed to be Net Zero capable. Fast tracked to address the housing needs of residents displaced by Tropical Storm Irene, the project was one of the first multifamily housing projects in Massachusetts to achieve net zero energy capability. HEA designed the building’s mechanical, electrical, plumbing and fire protection systems.
HEA’s HVAC design included individual high-efficiency (23+/- SEER, 9.25 min. HSPF) mini-split heat pump systems to heat and cool to each residential unit as well as a high-efficiency Variable Refrigerant Flow (VRF) system to condition the common spaces. VRF systems constantly modulate the amount of refrigerant being sent to evaporators. As such, VRF units work only at the required rate, resulting in less energy consumption than on/off systems.
Outdoor air to common spaces is provided by energy recovery ventilators (ERVs). Each ERV is equipped an enthalpy cross-counterflow heat exchanger, hot water post heater, frost protection, bypass for free-cooling and two supply/exhaust fans with ECM motors for optimal energy efficiency. ERVs also provide ventilation for residential units through outdoor air delivered to the corridors.
A high efficiency condensing boiler provides supplemental heat to common areas located along the building’s perimeter as well as each ERV’s hot water coil. Boiler controls include supply water reset based on outdoor air temperatures, allowing the supply temperature to be reduced as outdoor temperatures rise.
Domestic hot water for residential units is provided by instantaneous water heaters. Each serves two units. Low flow plumbing fixtures were specified throughout the building.
LED lighting and occupancy sensors are utilized throughout the building. Since seniors have special lighting needs, particular attention was placed eliminating abrupt changes in lighting levels between contiguous areas. The project also included a rooftop-mounted photovoltaic system to provide on-site green power generation capability. The building faces south for optimum solar exposure.
Fire Protection Systems