ILFI's approach to achieving net-zero energy began by lowering the building’s electricity consumption as much as possible before designing renewable energy systems to offset that consumption. Conservation strategies were organized into passive and active approaches. The net impact of these conservation measures reduced Brock’s predicted energy consumption down to a very low Energy Use Intensity (EUI) of 15.5 kBTU/sf/yr.
Energy modeling efforts began during the earliest design phase and informed energy conservation priorities, as well as the building orientation and form. The team developed a natural ventilation strategy to address bi-directional wind patterns. The building was designed to take advantage of the natural breezes prevalent near the Chesapeake Bay, with windows and even walls designed to open up and take advantage of airflow. The building was designed to maximize diffused daylighting from the north while shielding the building interior from direct sunlight from the south. In all of these cases, extensive computer modeling was used to optimize each of these selections. Even the roof and wall construction were modeled to determine the optimal R-value.
An iterative design process was also used to determine the most energy-efficient active systems to implement on the project. The mechanical system uses a variable-refrigerant flow (VRF) system with geothermal wells. Electric lighting was modeled to ensure that target light levels would be provided and with no overlit spaces. In addition, a photosensor dimming-control system was used in almost every space to reduce the electric lighting when sufficient daylight is present.
Photo: Courtesy of Dave Chance
