Trane TRG-TRC014-EN manual Glossary, supply air Conditioned air delivered to a space

Glossary

constant-volume fan, packaged so that the airflow paths are in series.

This provides a constant volume of supply air to the space when operating.

static regain duct design method Method of designing an air duct system that strives to maintain a fairly consistent static pressure throughout the entire duct. Recommended for sizing the supply ducts upstream of the terminal units in a VAV system. The design of a static regain duct system often requires the use of a computer program.

supply air Conditioned air delivered to a space.

supply duct static-pressure control Method of VAV system static-pressure control that mounts the static-pressure sensor somewhere in the supply duct system, allowing the supply fan to decrease speed and lower the static pressure in the system under part-load conditions.

supply duct system Transports the primary air from the central air handler to the VAV terminal units and then on to the space diffusers.

system resistance curve Plot of the static pressure drop that the system (including the supply ductwork, duct fittings, terminal units, diffusers and return grilles, coils, filters, dampers, and so forth.) creates over a range of airflows.

unoccupied mode Typical nighttime operating mode of the system. The building does not require ventilation because it is not occupied, and the space temperatures are controlled to unoccupied set points.

variable-pitch blade control Method of fan modulation used on vaneaxial fans. The capacity of the fan is modulated by adjusting the pitch angle of the actual fan blades.

variable-air-volume system Type of air-conditioning system that varies the volume of constant-temperature air supplied to meet the changing load conditions of the space.

VAV reheat terminal unit Type of single-duct VAV terminal unit that can provide space heating using a small heating coil.

VAV terminal unit Sheet-metal assembly installed upstream of space diffusers. Its purpose is to vary, with the purpose of varying the quantity of air delivered to the conditioned space.

warm-up/cool-down mode Typical operating mode for transition from the unoccupied mode to the occupied mode. It establishes the space occupied comfort conditions as rapidly as possible because they were allowed to drift from occupied set point during the unoccupied mode, usually to save energy.

TRG-TRC014-EN 89