Glossary of Applied Air HVAC Terminology

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Saturation Temperature
Also referred to as the boiling point or the condensing temperature. This is the temperature at which a refrigerant will change state from a liquid to a vapor or visa versa.
Sensible Cooling Load
e heat gain of the building due to conduction, solar radiation, infiltration, appliances, people, and pets. Burning a light bulb, for example, adds only sensible load to the building. This sensible load raises the dry-bulb temperature.
Sensible Heat
Heat, that when added or removed, causes a change in temperature but not in state.
Sound Attenuators
Components which are inserted into the air distribution system and designed to reduce airborne noise which is propagated along the ducts.
Specific Speed
A dimensionless parameter based on fan rotational speed, flow rating and pressure rating. It's a tool used to select the type of fan for a specific application. Each Different fan type achieves peak efficiency at a unique specific speed range.
Split System
Refrigeration or air conditioning installation, which places condensing unit outside or away from evaporator. These unit are connected together by a supply and return refrigerant lines.
Standard Cubic Feet Per Minute (SCFM)
The volumetric rate of airflow at standard air conditions.
Static Efficiency
A measure of an air mover's efficiency based on its air horsepower in terms of flow and static pressure vs. required shaft input power.
Static Pressure
The difference in air pressure between the suction side and pressure side of the blower. Unit of measure is inches of water column (in. wc) or Pascals (Pa).
Stator
The part of the motor that is fixed, typically found in the hub of the fan.
Subcooled Liquid
Liquid refrigerant which is cooled below its saturation temperature.
Superheated Vapor
Refrigerant vapor which is heated above its saturation temperature. If a refrigerant is superheated, there is no liquid present.
System Impedance
The resistance to air flow when moving air through an airflow system. Examples: air filters, air grilles and abrupt changes in flow direction.
System Operating Point
The point of operation of the air mover on its air performance curve. It is described by an airflow and static pressure point. The operating point is that point on the air mover performance curve where the system resistance curve crosses the air performance curve.