Video Overview
Learn how air handling units are designed to operate and view a cooling-type unit at a recreational facility.
An air handling unit (AHU) takes outside air, filters it, and pushes it through a building using ductwork. The AHU can also complement a heating and cooling system, such as a chiller, cooling tower, or boiler, and will contain heating and cooling coils to provide the distribution of comfort air. The video reviews a cooling-only AHU at large recreational facility. To learn about inspection procedures and common defects, take the Inspecting Commercial HVAC Systems Online Course.
Design Variable Examples
An AHU system does not provide a standard sequence of operation because there are so many design variables. Some of the differences in units are as follows:
- Some provide only airflow, and the heating and cooling is located in a Variable Air Volume Box (VAV).
- Some provide constant cooling from a chiller and cooling tower, and heating is provided through a resistance (coil) heating element.
- Some provide constant cooling from a chiller and cooling tower, and heat is provided by a boiler and through a heat-emitting device located in the AHU.
- Some provide constant cooling from a chiller and cooling tower, and heat is provided by a boiler through a heat-emitting device located in a VAV.
The AHU shown in the video is located in the center of a recreational facility, and is not next to an outside wall. Fresh air is provided to this unit by a different air handling vessel located on the outside of the building, which forces air over to the unit. The air passes through filters and a simple cooling coil loop. This particular AHU is a cooling-only unit. Chilled water, produced by a chiller and cooling tower, comes through pipes into the coil. The air passing over these chilled pipes is what produces the cool air that is distributed throughout the building.
Cooling-Only AHU
Additionally, the AHU shown in the video works in conjunction with VAV boxes installed throughout the building that function as zoning devices. VAV systems allow a building to maintain more balanced conditions by regulating airflow to different areas, helping equalize temperatures throughout the space. The Variable Air Volume (VAV) Boxes in Commercial Buildings video reviews how the VAV boxes at the recreational facility operate as part of the AHU and other HVAC systems. For a downloadable inspection procedure guide, refer to the AHU and VAV Box Inspection Checklist.
Commercial HVAC Inspection Training
Learn more about AHU and VAV systems in the Inspecting Commercial HVAC Systems Online Course, which includes a downloadable coursebook, inspection checklists, and a certificate upon completion.