Search results
Results from the WOW.Com Content Network
Most commonly, VAV boxes are pressure independent, meaning the VAV box uses controls to deliver a constant flow rate regardless of variations in system pressures experienced at the VAV inlet. [2] This is accomplished by an airflow sensor that is placed at the VAV inlet which opens or closes the damper within the VAV box to adjust the airflow. [2]
Such a control sequence is supported by a pollutant sensor (e.g. carbon dioxide sensor), a variable frequency drive (VFD) on the fan supplying the zone, individual VAV boxes with reheat serving each space in the zone, and airflow measuring stations. [4] Research has been conducted on the application of DCV in constant-air-volume (CAV) systems.
Most new commercial buildings have VAV systems. VAVs may be bypass type or pressure dependent. Pressure dependent type VAVs save energy while both types help in maintaining temperature of the zone that it feeds. Abbreviated VAV. zoning system A zoning system sections a building or a space into zones which are controlled independently of each other.
A damper is a valve or plate that stops or regulates the flow of air inside a duct, chimney, VAV box, air handler, or other air-handling equipment. A damper may be used to cut off central air conditioning (heating or cooling) to an unused room, or to regulate it for room-by-room temperature and climate control - for example, in the case of ...
DOAS air handling unit with heat recovery wheel and passive dehumidification. A dedicated outdoor air system (DOAS) is a type of heating, ventilation and air-conditioning system that consists of two parallel systems: a dedicated system for delivering outdoor air ventilation that handles both the latent and sensible loads of conditioning the ventilation air, and a parallel system to handle the ...
For example, a conventional heat pump system used to heat a building in Montana's −57 °C (−70 °F) low temperature or cool a building in the highest temperature ever recorded in the US—57 °C (134 °F) in Death Valley, California, in 1913 would require a large amount of energy due to the extreme difference between inside and outside air ...
Also called resource cost advantage. The ability of a party (whether an individual, firm, or country) to produce a greater quantity of a good, product, or service than competitors using the same amount of resources. absorption The total demand for all final marketed goods and services by all economic agents resident in an economy, regardless of the origin of the goods and services themselves ...
Some examples of digital inputs would be a door contact switch, a current switch, an air flow switch, or a voltage-free relay contact (dry contact). Digital inputs could also be pulse inputs counting the pulses over a period of time. An example is a turbine flow meter transmitting flow data as a frequency of pulses to an input.