Bosarge Family Education Center, 2013 ZNEBA Winner. Robert Benson Photography.
Coastal Maine Botanical Gardens
The winner of NESEA’s annual Zero Net Energy Building Award offers not only energy efficiency, but ideally also comfort, affordability, reliability, and elegance. Congratulations to everyone involved in this project. You are leading the charge on making sustainable energy practices the norm in the built environment.
Architects: Maclay Architects & Scott Simons Architects
Energy Consultant: Energy Balance
Mechanical & Electrical Engineer: Allied Engineering
Sustainability and LEED Consultant: Thornton Thomasetti
Structural Engineer: Becker Structural Engineers
Civil Engineer: Knickerbocker Group
General Contractor: HP Cummings
Building Systems Fabricator: Bensonwood
Lighting Designer: J & M Lighting Design
Acoustical Consultant: ACENTECH
Commissioning Engineer: Investment Engineering
Specifications: Lowell Specifications
Landscape Architect: AECOM
Our winner in a climate with the most heating degree days
Read what the judges had to say…
“After much deliberation, this year’s judges chose to give the 2013 Zero Net Energy Building Award to Maclay Architects of Waitsfield, Vermont, who collaborated with Scott Simons Architects of Portland, Maine on The Bosarge Family Education Center in Boothbay, Maine. With a record number of entries this year, the judges had to identify a project that particularly stood apart from the others. The Bosarge Family Education Center, part of the Coastal Maine Botanical Gardens, did so in two major areas: building innovation and public impact.
Not only did this northernmost building achieve net zero energy in a challenging climate with the most heating degree days, it was also pre-assembled primarily off-site. The building’s impressive airtightness levels are a testament to the builder, Bensonwood of Walpole, New Hampshire, the design team and the process. It also brings great hope to the industry which has relied mostly on custom, site-built and intensively resourced structures in order to achieve such energy performance levels.
The center was also recognized by the judges as a beautifully designed, natural light-filled building that echoed rural Maine forms in a crisp, warm and contemporary way, a structure that represents proudly the potential of what a net zero building can look like. The added flexibility to the interior spaces allows for the possibility of housing multiple occupancy conditions, something for which a low energy building is ideally suited.
Maybe most importantly, of all project submissions, this building represents the net zero building with the greatest potential public impact. As the only entry of the group and the first NESEA Zero Net Energy Building Award winner that is a public, non-denominational building, this building will serve as a showcase to many, wearing its credentials on its sleeve through “truth walls” and live energy monitoring.”
In the words of Maclay Architects…
“The Bosarge Family Education Center at the Coastal Maine Botanical Gardens was designed through a collaboration between our firm, and a local Maine architecture firm, Scott Simons Architects.
The client wanted to construct a new education center adjacent to their existing visitor’s center to serve as a model of sustainable, energy-efficient design. From the outset, the client outlined strict environmental guidelines with the goal of a LEED-Platinum, net-zero, beautiful building blending into the context of the surrounding gardens. The building was also to be an active teaching tool by outwardly demonstrating energy and resource conservation to visitors.
This net-zero building is designed around a central open gallery: a gateway to the gardens. Two wings extend from this central core into the landscape, one housing administrative functions and the other flexible public space. Extensive glass enhances the connection to nature for occupants.
The pre-determined site was a confined parcel adjacent to an existing visitor’s center. Located in a valley, this site presented a challenge to the design team of maximizing the solar access critical to net-zero performance. In addition, the client wanted to preserve as many of the large coniferous trees as possible. The site, along visitor’s central circulation path, allows the staff to be connected to the arrivals and departures of guests.
The orientation of the building allows for the use of passive solar strategies, optimizes the orientation of the roof-mounted PV and solar hot-water panels, and minimizes the impact to the existing site and trees. Meters provide real-time energy data for all systems. Signage and a “truth wall” educate visitors about the buildings sustainable features. The highly insulated building envelope, high levels of daylight, and automatic controls optimize occupant comfort.
The client set forth a strict schedule for the project in order to preserve the experience of visitors during the high summer season. To meet this tight schedule a panelized construction system was used which allowed for off-site fabrication, minimized on-site waste, site impact and time. This project is the first net-zero project by our office completed utilizing a panelized system, and through careful thought and construction, it meets the air infiltration standards required for net-zero buildings. The panelized process offers a level of control and precision in a factory environment. The envelope design and building assembly now established within the prefabrication parameters can be adapted for other projects.
The building design brings to life the mantra, “If a plant designed a building…”
The Bosarge Family Education Center is occupied by office personnel full-time during working hours and is often used by visitors and for larger group activities on the weekends and evenings, especially during the summer season. The office staff in the building comprises 10-20 people depending on seasonal occupancy and daily needs. Events in the space are common and include 20-200 people. Therefore, occupancy is assumed at a higher number than just office staff.
≈ 300 Days of Occupancy
≈ 9,000 Person Days of Occupancy
COST OF CONSTRUCTION
Square footage of conditioned space – 8,200 SF
Construction Cost – $3,200,000
Cost/SF – $390/SF
MAJOR ENERGY RELATED SYSTEMS
- Building Envelope
Sub Slab – R-20, 4” EPS rigid insulation
Slab Edge Joint – R-20, 4” EPS rigid insulation
Slab Perimeter – R-20, 4” EPS rigid insulaiton
Above Grade Wall – R-40, dense pack cellulose in 11–7/8” I-stud cavity
Roof – R-60, dense pack cellulose in 16” I-stud cavity
- Doors/Windows (U-value and SHGC):
Windows: Low-e, tri-pane, argon filled, FSC certified
0.16 U-value, 0.24-0.16 SHGC, 0.57-0.629 VLT
0.154 U-value maximum
Skylights (Type 1) 16 mm nanogel-filled polycarbonate inner layer
Skylights (Type 2) Triple-glazed, low-E2, argon filled, 0.27 U-value
Exterior doors, Low-E2, tri-pane, argon filled, 0.42 U-value
- Mechanicals Systems
Space heating – Mitsubishi, single-phase air source heat pump
Space cooling – provided by air source heat pump if needed
Hot water – solar domestic hot water
Ventilation – manual and automatically operated clerestory windows and skylights provide venting, ERV with automatic CO2 and airflow sensors provides all ventilation while recovering ≈ 70% of heat from exhausted air.
- Renewable Energy
135 rooftop panels & 102 ground mounted panels
45 kW peak power
47,000 kWh estimated annual output
LED, High-efficiency and Super-T8 throughout
Daylight dimming and cutoff in classrooms in all public spaces, bi-level (manual on and auto off) in offices and other small spaces
To see the poster board presentation for the Bosarge Family Education Center please click here.