Glossary for expressions used in facilitiy engineering

Adiabatic cooling The process of cooling air by adding humidification.
Air volume Rate of airflow, normally expressed in cubic feet per minute (cfm) or cubic meter per hour (cmh).
Air Handling UnitAHUAn air handler, or air handling unit is a device used to condition and circulate air as part of a heating, ventilating, and air-conditioning (HVAC) system.
Building Automation SystemBASA computer-based control system installed in buildings System that controls and monitors the building’s mechanical and electrical equipment such as ventilation, lighting, power systems, fire systems and security systems.
Building Control SystemBCSA computer-based control system installed in buildings System that controls and monitors the building’s mechanical and electrical equipment such as ventilation, lighting, power systems, fire systems and security systems.
Building Management SystemBMSA computer-based control system installed in buildings System that controls and monitors the building’s mechanical and electrical equipment such as ventilation, lighting, power systems, fire systems and security systems.
Bypass A pipe used to convey fluid to or around another pipe.
Cooling CoilCC 
Central Processing UnitCPUThe part of a computer that inteprets and executes instructions.
Cooling WaterCWEnergy contained in cold water used to supplement energy recovery.
Dehumidification The process to remove atmospheric moisture.
Dry Bulb TemperatureDBThe temperature of air measured by a thermometer freely exposed to the air but shielded from radiation of moisture.
Dew PointDPThe atmospheric temperature (varying according to pressure and humidity) below which water droplets begin to condense and dew can from.
Exhaust AirEACommonly known as return air. The air mechanically removed from a building.
Electrical CabinetECA 
Energy Recovery CoilERCEnergy Recovery Heat Exchanger
Exhaust Heat Recovery CoilEHRC 
Energy Recovery SystemERSA system to reclaim and recycle waste heat from other sources, such as building exhaust air, in order to reduce the need for the primary energy source.
Filter A device to remove contaminants.
Free-CoolingFCAn economical method of using low external air temperatures to assist in chilling water that can be used in mechanical processes.
Hydronic Module Prefabricated unit containing mechanical equipment, controls, valves and sensors.
Heat Recovery CoilHRC 
Heat Recovery SystemHRSA system to reclaim and recycle waste heat from other sources, such as building exhaust air, in order to reduce the need for the primary energy source.
Humidity relative% r.H.The ratio of the partial pressure of water vapor in an air-water mixture to the saturated vapor pressure of water at a prescribed temperature.
Heating, Ventilation, Air ConditioningHVAC 
Heating WaterHW 
Latent Heat The quantity of heat absorbed or released by a substance undergoing a change of state.
Light-Emitting DiodeLEDA device that lights up and displays information when electricity passes through it.
Outside AirOAAir taken from the external atmosphere not previously circulated through the building.
Pre-Heat CoilPHCPreheat elements are the first element in the air stream following the intake and prefilter, which is a position that allows them to protect the rest of the system and building from freezing air.
Plate & Frame Heat ExchangerPHxA plate heat exchanger is a type of heat exchanger that uses metal plates to transfer heat between two fluids.
Plate & Frame Heat Exchanger Cooling WaterPHE-CW 
Plate & Frame Heat Exchanger Heating WaterPHE-HW 
Return AirRADescribes the air leaving a room. It may be recyled or purged to the environment.
Return Air HumidifierRA-HUM 
Running Around Recovery SystemRARSA very efficient type of energy recovery system that consists of heat exchangers in the supply and exhaust air streams, piping (containing a heat transfer fluid) between the heat exchangers and a pump. Sophisticated systems communicate with the BMS and include controls and monitoring equipment.
Re-Heat CoilRHC 
Sensible Heat Heat exchanged by a body or thermodynamic system that has as its sole effect a change of temperature.
Supply AirSAAir that has been conditioned entering a space.
Supply Air HumidifierSA-HUM 
Supply Heat Recovery CoilSHRC 
Supply Heat Recovery Coil - Pre HeaterSHRC-PH 
Supply Heat Recovery Coil - Supplenmentary HeaterSHRC-SH 
Uninterruptable Power SupplyUPSA device that supplies power on a short term basis when a primary power source is lost.
Ventilation The process of "changing" or replacing air in a space to provide high indoor air quality.
Variable Frequency DriveVFDPower control conversion devise for 3 phase motors.
Virtual Private NetworkVPNA network that uses a public telecommunication infrastructure, such as the Internet, to provide remote offices or individual users with secure access to their organization’s network.
Wet Bulb TemperatureWBThe temperature at which water, by evaporating into air, can bring the air to saturation at the same temperature.
Watchdog TimerWDTAn electronic timer that is used to detect and recover from computer malfunctions.