High Velocity Systems
High velocity heating and cooling systems use a special fan coil and air handling unit that generates high pressure air forced through small diameter ducts. The main supply trunk is either a rectangular or round duct that supplies air to flexible, insulated, 2" diameter plastic feeder ducts. Air passes through sound-suppressing tubing at the end of a duct run before entering the room through a plastic collar fitting. According to manufacturers, air is supplied at 440 to 1200 cubic feet per minute (CFM).
High velocity systems use standard outdoor condensing units for air conditioning and heat pump systems. As an option, a water coil can be mounted in the air handling unit for boiler heating or chilled water cooling. Alternatively, adding a bank of electric heating elements to the air handler can provide heating capability to a high velocity air-conditioning system. High velocity system air handlers can satisfy cooling capacities between 18,000 and 60,000 BTUH and heating capacities between 24,000 and 143,000 BTUH.
The mini duct air distribution system is quick and easy to install. The small flexible, insulated tubing is designed to fit the existing structure without major remodeling. The tubing requires approximately 1/10th the space of conventional central air conditioning.
High velocity air distribution systems are distributed by certified contractors, or may be purchased directly from the manufacturer or distributor. Howecer, it is important to note that some heating and cooling professionals are unfamiliar with high velocity ducts. The systems commonly require a greater number of outlets--(about 5 outlets per ton of cooling, or one outlet for every 2400 BTUs of heating), --adding to material costs and installation time.