A Complete Guide To Air Handling Units
What is an air handling unit? An air handling unit, or air handling unit is a machine used in a manufacturing setting to regulate and distribute air as a part of an air conditioning, ventilation, and heating system. An air handling unit is usually a large heavy metal box with many heat-absorbing or cooling components, blowers, air filters or blowers, intake ducts, noise dampers, and duct return pipes. Air handling units are sometimes called air compressors. They can be found in refrigeration lines, air conditioning systems, welding or metal processing plants, chemical plants, pulp mills, pharmaceutical plants, printing plants, transportation processes, and many other businesses. In these applications, the air handling unit is the central air processing unit.
A typical air handling unit has an integrated design with thermostat control, temperature and humidity alarms, separate blower and air filtering mechanisms, separate air handling sections, and electrical wiring. Air handlers must have a constant airflow supply to operate effectively. Air handlers should have well-functioning controls and adequate insulation to protect mechanical parts from excessive heat, cold, or both. This equipment should also have sufficient power to accommodate any anticipated load on it.
When an air handling unit is installed, there may be an existing duct system in use. If so, this duct system can be utilized to expand the air volume in the duct system to accommodate the additional air handling equipment. Some existing duct systems may also be expanded to include air ducts that extend to interior spaces such as offices or machine rooms. The expansion of ductwork improves system efficiency by improving air circulation, reducing moisture absorption and evaporation, and reducing duct noise.
The air handling unit's cooling fan is located in the intake duct and is usually behind a door-mounted thermostat. The intake fan is powered by a set amount of horsepower. It pulls air from the intake duct and passes it through a precision-insulated, sealed air flow meter or thermal measuring device. The thermal measuring device measures the air flow and changes are noted. The cool air is then blown by the air handling unit's blower into the appropriate duct system for the application. The air handling unit's control module then interprets the changes noted and modifies the desired temperature for the air flow.
The air handling unit's blowing fan does not have a direct connection to the receiving air supply. However, it does create a vacuum, which is transferred to the mixing box. The mixing box is typically a closed box made of metal such as sheet metal, but it can be constructed from other materials as long as it is sufficiently rigid to remain in place when air pressure is applied to it. An air handling unit usually installs an air filter in the drawing or blow-through path of the supply so that the air entering the mixing box is cleaned of dust and particulates before entering the recipient.
A final component is an air handling unit that contains one or more heating coils. Heating coils are placed in an enclosed metal housing so that air passing through them can heat up and radiate heat into the recipient. The air handling unit also contains a power-driven heater. This unit is connected to the heating coils through electrical wiring or an air handling unit duct system.