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Home Industry Operative Principle of an Air Handling Unit (AHU)

Operative Principle of an Air Handling Unit (AHU)


Air Handling unit or AHU is an assembly of air conditioning components (such as fans, cooling coils, filters, humidifiers, and dampers) integrated into a self-contained package and installed as a single unit, which is connected to a system of metal ductwork that distributes the conditioned air.

There are mainly two types of AHU:
Simple flow: the AHU, whether works in 100% fresh air, or air intake, or works with the two of them.

Dual flow: the AHU is working with the most optimal configuration, by choosing between the quantity of fresh air, totally treated air, air intake, return air, according to the situation.

How does a simple flow AHU work? It is very easy to understand:
The AHU pumps the designed external air, which will be treated in temperature and humidity, as well as the quality of components with different types of filters. This treated air will be carried to respective areas using ducting.

For a dual flows AHU, besides the first objective explained previously, the AHU will extract the air from the areas that can’t be recycled back in the AHU (air too polluted or areas which require a percentage of extracted air) and will be rejected out of the structure.

Primary Objectives of the AHU:

  • Fresh air intake (which replaces the air polluted)
  • Air treatment (by filtration)
  • Humidity and temperature control of the air supply
  • Structure easy to install in each type of architectural configuration
  • Minimal surface facilities are required.

The AHU provides pre-cooling (preheating) of the ventilation air and thus take care of only a relatively small part of the cooling (heating) load. Besides, the energy for pre-cooling (preheating) does not come from the AHU itself but is provided by an external source, such as a chiller (boiler or furnace). Some AHUs like dual-stream VMC is working with exchanges boxes for effecting heat energy recovery, thanks to the use of the heating recovered to heat the air intake.

  • The dual-flow AHUs know how to work according to different working systems.
  • The different types of filtration:
  • Total recycling: no fresh air is brought, air treatment is working as a closed circuit, only with the ambient air,
  • Partial recycling: part of the air treated is rejected and replaced by fresh air.
  • 100% Fresh air: the air intake flow equals the air supplied. It becomes, therefore, interesting to retrieve the energy brought by a heat recovery unit on the air intake ‘polluted’.

At Waves Aircon, an ISO 9001-2015 certified company, we are a pioneer in the field of air management systems and equipment. we believe that clean and optimized air supply is the key to a healthy living and productive working environment.

We are the sole manufacturing unit in India, to be certified by the ‘Eurovent’, which is the European Federation of 15 national associations which evaluates the products of 11 countries which works in the sectors of refrigeration, air conditions as well as ventilation.

Our expertise is in making 100% customized solutions for our customers. We maintain the highest standard possible in the manufacturing process as per international norms and committed to providing an unrivaled depth of range and expertise in all aspects of the design, manufacture, testing, installation, service, and maintenance of our air handling equipment.

We have so many examples of customized AHU, that it is just not possible to include everything in just one page, but we assure you that we are the best in this business and YOU are in safe hands,

For our complete product range, please visit our website or post your query at