The Nations First Net-Zero Electric Commercial Building

The 31 Tannery Project, located in Branchburg, N.J., serves as the corporate headquarters for Ferreira Construction, the Ferreira Group, and Noveda Technologies. The building includes nine miles of radiant heat (80 zones), high performance rooftop units, a 96% efficient condensing boiler plant, 223 kW dc solar photovoltaic system, solar domestic hot water, integrated Web based direct digital controls system and pervasive voice/data/video system with kiosk displays.

During construction, monitoring for the two-story building’s renewable energy systems, conventional energy systems and high-efficiency systems was installed along with standard building controls. This allowed the building team to learn from operations and interactions of the systems, a critical component of commissioning. System integration and interactivity, employee awareness, dedication and feedback, and visualization and commissioning displays contributed to the sustained level of performance.

Performance Process

How did a company that builds roads and bridges achieve a net zero building? Ferreira’s Director of Engineering, Edward Brzezowski, P.E., Member ASHRAE, developed the project, drawing on their experience in building design, sustainability, construction management, commissioning and renewable energy. Using standard construction materials and readily available resources, the team applied three approaches to maximize results and return on investment: energy efficiency, renewable energy, and real-time monitoring and visualization of energy.

To explain the process and benefits of energy efficiency + renewable energy + monitoring and visualization, the Ferreira team uses a diet + exercise + personal trainer metaphor. Dieting or adding energy efficiency is a good start for an out-of-shape building.

Adding exercise or renewable energy increases results. However, having a personal trainer, or a monitoring and visualization solution, to watch the progress, track results, motivate by showing the progress, refocus efforts when slipping, say what to do next, and say if things are being done right provides the greatest results in the shortest period of time and allows for continuous improvement. All three components helped achieve the net zero electric building.

Grid-Tied Photovoltaics

Attached to 31 Tannery’s standing seam metal roof are 1,276 solar photovoltaic panels. Being new construction, rooftop penetrations and systems, such as the rooftop unit (RTU) and shop ventilation system, were kept to the north side of the building to maximize performance of the rooftop solar photovoltaic array. The solar electric system produces on average 500 kWh per day in the winter and 1,300 kWh per day in the summer. On a cloudy or overcast day, the combined inverter output typically measures 30–40 kW ac. On a sunny day, design conditions of 200 kW ac have been reached.

Electric Room

The electric room includes the building’s main and distribution panels, two 100 kW ac 277/480V three phase solar inverters, and a transfer switch for a future 200 kW gas-fired emergency generator. Although solar panels generate electricity in dc (direct current) power, most building systems use ac (alternating current) power. Inverters connected to the rooftop solar panels convert the dc (kW dc) power from the solar panels to ac (kW ac) power. The inverters have a capacity of 223.3 kW dc and allow LAN-based communications. Custom software monitors, in real time, the energy use and flow in and out of the building.

Live Building Data

For more information about this project and other Noveda projects please visit www.noveda.com or wikipedia

Additionally you can visit the sister 31 Tannery Project