Discusses field data from two buildings with cold air distribution which indicate that the fan energy consumption of continuously-operating, fan-powered mixing boxes can offset the energy savings resulting from downsized central fans. Presents the fan energy data from buildings and discusses them, along with simulations of alternative air distribution options. Also presents estimates of relative fan power based on nameplate ratings and theoretical calculations. Discusses options for minimising fan energy in cold air distribution systems.

KEYWORDS: Buildings, air conditioning, low temperature, air, fans, energy consumption, air terminals, models, calculating, air distribution.