Improve energy and comfort performance of large office buildings using integrated interior and exterior zone air-handling units

The interior zone and exterior zone air-handling units (AHU) can be connected through their return air ducts to become a new air-handling unit system, named OAHU system, which allows optimal choice of outside air intake and decouples sensible and latent cooling in a zone with lower sensible
load. This minimum system modification reduces the building thermal energy consumption and improves indoor air quality in the zone of higher load. For a typical building in a hot and humid climate (San Antonio, Texas), the annual thermal energy savings is estimated to be 276 kilojoules for each square meter of floor area per year, or 24.3 kBtu for each square foot of floor area per year. For a cold climate (Minneapolis, Minn.), the annual thermal energy savings is estimated to be 195 kilojoules heating and cooling energy for each square meter of floor area, or 17.2 kBtu for each square foot of floor area. This paper presents the system models, the simulation procedures, and the
simulation results.