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The role and application of AHU in the HVAC system

What is AHU?

AHU (abbreviated as Air Handling Unit) is a heat exchanger and heat treatment device that cleans the air commonly used in HVAC systems.


  • Commonly used in large air-conditioned spaces such as commercial centers, conference centers, 5-star hotels, indoor gymnasiums, office buildings, etc.

  • Use in clean room projects with high requirements for air treatment such as operating rooms/hospital experiments, precision equipment production rooms, or food in factories...

AHU – Air Holding Unit

The principle of operation of AHU

Depending on the needs of users, the AHU operates with the primary function of cooling/heating along with other parts such as dehumidification, and clean air by HEPA filter, ...

  • The AHU supplies cold air to the rooms that need air conditioning through the supply air outlet and returns the air to the AHU through the return air outlet and mixes fresh air at the mixing box.

  • Fresh air before entering the AHU is filtered through a pre-filter, usually a coarse filter and a fine filter, in case clean air quality is required, use a HEPA filter.

The principle of operation of AHU

Depending on the specific projects, AHU has modules with specifications suitable for the project, but the AHU has the most basic components:

  • Fan

  • Heater

  • Cooler

  • Air filter

  • Protective case

structure of AHU

Specifications for selecting AHUs when designing HVAC systems to increase the air quality in the AHU

  • Total Capacity: kW

  • Sensible Capacity: kW

  • Supply Air Volume: l/s

  • Coil Entering Air Temperature (DB-WB): oC

  • Coil Leaving Air Temperature (DB-WB): oC

  • Fresh Air Volume: l/s

  • Fresh Air (DB-WB): oC

  • External Static Pressure: Pa

  • Cooling/Heating Water Flow: l/s

  • On-Off Coil Water Temp: oC

  • Main Filter Type: Panel/Bag/Hepa Filter

  • Supply Fan Power: kW

In addition, choosing a quality air filter that is suitable for the design capacity has an important influence on the quality of the clean air supplied to the room.

Let's find out more about VAF™️ air purifier products - VIET AIR FILTER


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