The objective of this project is to retrofit Department of War (DoW) buildings with Active Chilled Beam (ACB) systems to improve energy efficiency, optimize performance, and reduce costs. The initiative aims to demonstrate both the technical and economic feasibility of ACB systems in DoW facilities, while evaluating their impact on energy performance, heating, ventilating, and air conditioning system energy consumption. The project includes the installation of ACB systems at a demonstration site and the development of models, methods, and documentation to support the broader adoption of this technology.

ACBs are cooling terminal units that integrate a hydronic cooling system with primary ventilation systems to provide improved thermal and energy performance. Connected to the main air handling unit, an ACB includes a ventilation duct, air nozzles, and a heat exchange coil. It operates by utilizing a chilled water heat exchanger installed within a ceiling terminal to remove sensible cooling loads in occupied spaces. ACBs improve energy efficiency by reducing fan energy use, improving chiller performance with relatively warm water, and eliminating the need for reheating. They also offer benefits such as lower maintenance costs due to fewer moving parts, suitability for retrofitting existing buildings with minimal space requirements, consistent ventilation rates, low noise levels, and improved occupant comfort. In this project, the ACB system will be designed and customized to improve performance and efficiency based on a thorough building assessment. Detailed installation instructions will be developed and the ACB system will be installed at the selected demonstration site.

More energy efficient and flexible building energy systems reduce annual operating costs and can improve buildings’ resilience to natural or man-made disruptions of the commercial electric utility. For the selected DoW facilities, the retrofit solution with ACB could provide several significant benefits. The improved efficiency will result in a 15% to 35% reduction in energy consumption and corresponding cost savings. ACB systems achieve this primarily through three factors: fan energy savings, cooling energy savings, and the elimination of reheating. The cost savings go beyond lower energy consumption; ACBs offer lower maintenance costs as there are no moving parts, no filters, and no condensate trays. Compared to fan coil unit systems, life cycle maintenance costs are only 5.36% over 20 years. Occupant comfort is also improved, as ACBs move air through slot diffusers using the Coanda effect, preventing direct airflow onto occupants and eliminating the need for dropped ceilings. (Anticipated Project Completion - 2028)