Comparison of energy consumption between displacement and mixing ventilation systems for different U.S. buildings and climates

A detailed computer simulation method was used to compare the energy consumption of a displacement ventilation system with that of a mixing ventilation system for three types of U.S. buildings: a small office, a classroom, and an industrial workshop. The study examined five typical climatic regions as well as different building zones. It was found that a displacement ventilation system may use more fan energy and less chiller and boiler energy than a mixing ventilation system. The total energy consumption is slightly less using a displacement ventilation system. Both systems can use a similarly sized boiler. However, a displacement ventilation system requires a larger air-handling unit and a smaller chiller than the mixing ventilation system. The overall first costs are lower for the displacement ventilation if the system is applied for the core region of a building.