How Altieri is Working Toward Net Zero Energy Design

When the Barnes Foundation Museum moved to Philadelphia from Merion, Pennsylvania, the foundation’s staff knew they needed to create a safe environment for the collection without sacrificing elegance. Their architect commissioned the help of Altieri, a consulting engineering firm that specializes in leading-edge engineering systems for cultural and educational buildings. The building was designed not only to visually complement the diverse artwork inside, but also to protect it for many years to come.

The building is LEED Platinum certified thanks to its super efficient mechanical, electrical, and plumbing (MEP) solutions. “When we design a museum, we understand that the owners are going to be living with it for the next century,” says Kristen Butts, associate principal at Altieri. “Sustainable design is central to what we do.”

As a conservation-focused organization, it was important to the Barnes Foundation team that the museum was designed to minimize environmental impact. As a nonprofit, they also want to keep the utility bills low. The energy model developed during design showed a 44% energy improvement over the baseline model set by LEED. Due to the museum’s popularity, the occupancy far exceeded standard occupancy profiles for museums. After the building had been in operation a few years, the energy model was revisited to more closely record its occupancy. Though the metered energy usage was higher than originally documented, the energy efficiency measures became more pronounced. With Altieri’s design, the calibrated building model showed a 62% reduction in energy compared to the calibrated baseline, cutting back on HVAC, electrical, and water-related energy costs and resource use.

The space requires a consistent temperature of 70 degrees Fahrenheit and 50% relative humidity. This means often sub-cooling to dehumidify then reheat the building. “We discovered during the design of the project how important it was to have heat recovery chillers for this purpose,” says Butts, who completed the energy model and LEED filing for the project. Heat recovery chillers simultaneously provide cooling and hot water for use in reheat coils.

Ventilation is controlled through a dedicated air processing unit fitted with enthalpy wheel for heat recovery. The unit regulates the amount of outside air that passes into the building based on carbon dioxide levels in the space. These solutions reduce wasted energy by recovering heat and moisture from the exhaust airstream in winter, and transferring heat and moisture from the ventilation air to the exhaust air in summer, so when new air comes in it doesn’t require as large of a temperature and humidity adjustment.

The art collection is housed in a 12,000-square-foot gallery alongside rotating exhibits, classrooms, indoor gardens, and serene courtyards. In non-collection areas where requirements aren’t as stringent, active chilled beam systems control climate. One of Altieri’s guiding principles in designing mechanical systems for cultural institutions is to avoid using active equipment or hydronic piping systems above art exhibits or collections areas to avoid potential for leans or disrupting installations with maintenance.