The renovation of the historic Francis Scott Key Hall, a 48,000 SF dormitory at George Washington University, addressed outdated HVAC systems that surpassed their useful life. The university sought to update these systems in a way that supported its strategic goal of enhancing energy efficiency and reducing its carbon footprint. To achieve this, the university enlisted B&N to develop comprehensive design/build plans for mechanical, plumbing and electrical renovations.
Energy Efficient Solutions
One key solution was the installation of a magnetic-bearing chiller in the cooling plant. This chiller was designed to operate as a "low lift machine," with the ability to receive cooler condenser water from the tower during the fall and spring seasons. This approach helped achieve the lowest kilowatts per ton for the entire cooling plant.
Simultaneously, the building's ventilation system underwent improvements to deliver sufficient outside air to offset total building exhaust. B&N increased ventilation to enhance air quality and achieve proper building pressurization, which minimizes the risks of vapor intrusion and mold growth. A dedicated outside air system with a reheat coil was introduced to provide neutral-temperature air to all spaces throughout the year. Despite the increased ventilation, which typically means higher energy usage, the facility’s overall energy costs were reduced by 27%.
The project also included a new condensing boiler plant equipped with fully redundant variable primary hot water pumps. Sizing all new heating coils for entering water temperatures of 140 degrees allowed the boiler plant to operate in condensing mode year-round, maintaining an efficiency of 92%. Additionally, a fully redundant condensing hot water heating plant with an improved recovery and booster pump system was introduced to further reduce energy consumption.
To optimize control and ensure efficient operation, a new building automation system was integrated. This helped reduce energy consumption and simplify maintenance requirements over the system's lifetime.
For this project consideration of life cycle costs was crucial to ensure that the proposed solutions aligned with system constraints without costly upgrades for the owner. The Energy Utility Index (EUI) for the site was reduced by an impressive 29.7%. The renovation process included phased construction, which allowed the building to remain operational as a dormitory throughout the project. This comprehensive approach not only modernized the HVAC systems but also aligned with the university’s sustainability goals and minimized disruption to the building’s occupants.