| 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 Unit | AHU | An 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 System | BAS | A 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 System | BCS | A 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 System | BMS | A 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 Coil | CC | |
| Central Processing Unit | CPU | The part of a computer that inteprets and executes instructions. |
| Cooling Water | CW | Energy contained in cold water used to supplement energy recovery. |
| Dehumidification | | The process to remove atmospheric moisture. |
| Dry Bulb Temperature | DB | The temperature of air measured by a thermometer freely exposed to the air but shielded from radiation of moisture. |
| Dew Point | DP | The atmospheric temperature (varying according to pressure and humidity) below which water droplets begin to condense and dew can from. |
| Exhaust Air | EA | Commonly known as return air. The air mechanically removed from a building. |
| Electrical Cabinet | ECA | |
| Energy Recovery Coil | ERC | Energy Recovery Heat Exchanger |
| Exhaust Heat Recovery Coil | EHRC | |
| Energy Recovery System | ERS | A 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-Cooling | FC | An 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 Coil | HRC | |
| Heat Recovery System | HRS | A 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 Conditioning | HVAC | |
| Heating Water | HW | |
| Latent Heat | | The quantity of heat absorbed or released by a substance undergoing a change of state. |
| Light-Emitting Diode | LED | A device that lights up and displays information when electricity passes through it. |
| Outside Air | OA | Air taken from the external atmosphere not previously circulated through the building. |
| Pre-Heat Coil | PHC | Preheat 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 Exchanger | PHx | A plate heat exchanger is a type of heat exchanger that uses metal plates to transfer heat between two fluids. |
| Plate & Frame Heat Exchanger Cooling Water | PHE-CW | |
| Plate & Frame Heat Exchanger Heating Water | PHE-HW | |
| Return Air | RA | Describes the air leaving a room. It may be recyled or purged to the environment. |
| Return Air Humidifier | RA-HUM | |
| Running Around Recovery System | RARS | A 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 Coil | RHC | |
| Sensible Heat | | Heat exchanged by a body or thermodynamic system that has as its sole effect a change of temperature. |
| Supply Air | SA | Air that has been conditioned entering a space. |
| Supply Air Humidifier | SA-HUM | |
| Supply Heat Recovery Coil | SHRC | |
| Supply Heat Recovery Coil - Pre Heater | SHRC-PH | |
| Supply Heat Recovery Coil - Supplenmentary Heater | SHRC-SH | |
| Uninterruptable Power Supply | UPS | A 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 Drive | VFD | Power control conversion devise for 3 phase motors. |
| Virtual Private Network | VPN | A 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 Temperature | WB | The temperature at which water, by evaporating into air, can bring the air to saturation at the same temperature. |
| Watchdog Timer | WDT | An electronic timer that is used to detect and recover from computer malfunctions. |
