Air adjustments for every hour (ACH)
The quantity of periods for every hour that the volume of a distinct room or constructing is equipped or eliminated from that space by mechanical and organic ventilation.
Air handler, or air handling unit (AHU)
Central unit consisting of a blower, heating and cooling components, filter racks or chamber, dampers, humidifier, and other central devices in direct speak to with the airflow. This does not contain the ductwork by the constructing.
British thermal unit (BTU)
Any of quite a few units of electricity (warmth) in the HVAC market, every a bit far more than 1 kJ. Just one BTU is the electricity required to increase one particular pound of drinking water one particular diploma Fahrenheit, but the numerous air conditioning unique kinds of BTU are centered on unique interpretations of this “definition”. In the United States the electrical power of HVAC systems (the level of cooling and dehumidifying or heating) is in some cases expressed in BTU/hour as a substitute of watts.
Chiller
A product that gets rid of warmth from a liquid via a vapor-compression or absorption refrigeration cycle. This cooled liquid flows by pipes in a constructing and passes by coils in air handlers, admirer-coil air conditioning units, or other systems, cooling and ordinarily dehumidifying the air in the constructing. Chillers are of two kinds air-cooled or drinking water-cooled. Air-cooled chillers are ordinarily outside the house and consist of condenser coils cooled by admirer-pushed air. Water-cooled chillers are ordinarily within a constructing, and warmth from these chillers is carried by recirculating drinking water to outdoor cooling towers.
Coil
Devices that performs warmth transfer when mounted within an Air Managing unit or ductwork. It is heated or cooled by electrical usually means or by circulating liquid or steam in just it. Air flowing across it is heated or cooled.
Condenser
A element in the essential refrigeration cycle that ejects or gets rid of warmth from the technique. The condenser is the hot aspect of an air conditioner or warmth pump. Condensers are warmth exchangers, and can transfer air conditioning warmth to air or to an intermediate fluid (these kinds of as drinking water or an aqueous remedy of ethylene glycol) to carry warmth to a distant sink, these kinds of as ground (earth sink), a overall body of drinking water, or air (as with cooling towers).
Regular air volume (CAV)
A technique developed to present a frequent air volume for every unit time. This expression is applied to HVAC systems that have variable offer-air temperature but frequent air movement rates. Most household compelled-air systems are little CAV systems with on/off management.
Controller
A product that controls the operation of portion or all of a technique. It might simply just change a product on and off, or it might far more subtly modulate burners, compressors, pumps, valves, fans, dampers, and the like. Most controllers are automated but have consumer input these kinds of as temperature set details, e.g. a thermostat. Controls might be analog, or digital, or pneumatic, or a mix of these.