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
Carbon Dioxide
A by-product of natural gas combustion that is not harmful.
Carbon Monoxide
A colorless, odorless, highly poisonous gas produced when carbon burns without sufficient air nearby.
Centrifugal Fan
A device that draws air in axially and discharges it radially.
CFC (Chlorofluorocarbon)
A class of refrigerants. Generally refers to the Chlorofluorocarbon family of refrigerants. Sometimes called Freon.
CFD
Computational Fluid Dynamics is a computer-based mathematical model of fluids in a space.  In the HVAC industry CFD is used to simulate the direction, velocity, and temperature of air in a building.
CFM (Cubic Feet per Minute)
A standard measurement of airflow that indicates how many cubic feet of air pass by a stationary point in one minute. The higher the number, the more air is being forced through the system.
Charge
Amount of refrigerant placed in a refrigerating unit.
Chilled Beam
Chilled beams are a form of radiant cooling commonly used in europe.  Chilled beams can be "passive" (no external source of air is provided) or "active" (some amount of air is provided from an external source...usually the ventilation air required for a space).  Chilled beams are linear in nature normally measuring about 12" across and extending the length of a room.  Chilled beams are installed in the ceiling.
Circuit Breaker
A device that opens an electric circuit when an overload occurs.
Combustion
A reaction called rapid oxidation or burning produced with the right combination of a fuel, oxygen, and heat.
Comfort Zone
The range of temperatures, humidities and air velocities at which the greatest percentage of people feel comfortable.
Compressor
Pump of a refrigerating mechanism which draws a low pressure on cooling side of refrigerant cycle and squeezes or compresses the gas into the high pressure or condensing side of the cycle.
Condensate
The moisture collected on an evaporator coil.
Condensate Pump
A small pump used to pump condensate to a higher level.
Condenser Coil
Part of the outdoor portion of a split-system air conditioner or heat pump. By converting refrigerant that is in a gas form back to a liquid, the coil transfers heat carried by the refrigerant to the outside air.
Condensing Temperature
The temperature at which a vapor changes to a liquid.
Condensing Unit
Part of a refrigerating mechanism which pumps vaporized refrigerant from the evaporator, compresses it, liquefies it in the condenser and returns it to the refrigerant control.
Conduction
The transfer of heat through a solid material.
Convection
The movement of heat by fluid flow(e.g. air, water).