An air handling unit is a unit that controls how air moves through your home. The exchange unit is usually located outdoors and can be connected to both your heating and AC systems, moving hot or cold air as needed. Air handling units are the “lungs” of our neighborhoods. Together with heating or cooling systems (DX Coils, Chiller Groups, Boilers, etc…), they keep your home, office and all kinds of indoor spaces comfortable and clean in all seasons by managing the conditioned airflow.

The air handling unit cabinet houses the indoor components of your HVAC system and can fit additional devices that improve air quality and ventilation. This can include adding an electronic air filter, dehumidifier, and UV light for increased air quality and purification.

Many people are confused as to what the actual purpose of an air handling unit is and even though they are connected to their system. The critical point to remember is that air handling units do not heat or cool the air. Instead, these devices move air. If your heating system has another component that does this, such as a blower, then you don’t need an air handling unit either.

It is necessary to answer your question about how the air handling unit works differently for each system. Because the working principle of the air handling unit with heat recovery and the working principle of the air handling unit for comfort are not the same.

How does the air handling unit work?

The air handling unit structure consists of an aspirator to take in the air and a ventilator to supply the air. As the working condition of the air handling unit, fresh air must be transferred through the dampers. By adding a cooler to the air handling unit, water cooling can be provided in addition to ventilation. Within the working principle of the air handling unit, the system is prepared according to the environment to be used by adding the appropriate device for the purpose for which the system will be used.

If we answer your question in more detail about how the air handling unit works, we need to talk about the working conditions and structure of the air handling unit.

Air Handling Unit Cell Structure

The working principle of the air handling unit starts with the formation of the cell structure. Cells are manufactured in modular type and can be disassembled when desired. Cells are mounted to each other from the inside with bolts. When necessary, sight glass, start-stop button, door switch and lighting fixture inside are used for corrosion-resistant service covers. The air handling unit cell structure is resistant to 2500 Pa pressure.

Air Handling Unit Carcass

The carcass within the air handling unit structure is manufactured using an aluminium profile or optionally anodised aluminium. 40 carcass plastic corners for devices up to 1.000 – 15.000 m³/h capacity; 50 carcass and aluminium casting corner parts are used for devices larger than 15.000 m³/h capacity.

Air Handling Unit Panel

The panel system is of great importance for air handling unit working conditions. All panels are manufactured in a double-walled sandwich structure. The outer surface is PVC coated for air handling unit panels whose outer sheet thickness varies according to the standard size. For insulation, 20 -25 mm thick polyurethane is injected according to the capacity or stone direction of appropriate thickness is used.

Air Handling Unit Fans

Electricity and fan motor are on a single base in air handling units. Mounting of the fan base to the cell is made with anti-vibration rubber wedges. During the operation of the air handling unit, anti-vibration flexible bellows (connectors) are used in the installation of the fan-blowing nozzle to the cell.

Air Handling Unit Electric Motors

Another answer to your question about how the air handling unit works can be given by explaining how electric motors should be used. Double-speed motors can also be used in air handling units where three-phase motors are used as standard. Motors are IP54 or IP55 protection class.

Air Handling Unit Drive Mechanism

The drive system is the belt-pulley mechanism. Belts are narrow V belts. Pulleys are conical clamping bushes and cast. The drive mechanism is also included in the working principle of the air handling unit.

Air Handling Unit Heat Exchangers

The heating and cooling exchangers within the air handling unit structure consist of elements with aluminium lamellas on copper tubes. Collectors are made of anti-corrosive painted steel pipe. Heat exchangers are mounted in such a way that they can move on skids within the device.

Drip Trap and Condensation Pan

In air handling unit cooler exchangers, PVC or aluminium finned drip trap is used according to air passage rate. Drip trap blades are designed to hold maximum water and can be taken out of the device with slides.

Humidifier

Humidifier systems are also added to the power plant within the working principle of the air handling unit. There is a water-type deflector section, water circulation system, separator section, sealed control door and humidification pool of sufficient size.

Filters

Coarse Filtration (ISO 16890)

In the ventilation system; It is the filter group used as the first stage in the filtration of coarse particles (particle diameter of the largest pollutants).

Fine Filtration (ISO 16890)

In the ventilation system; It is a filter group used as the second and/or third stage for filtering fine particles. Ventilation systems such as air conditioning plants are the main places of use.

Absolute Filtration (HEPA)

Filters used for filtering pollutants with the smallest particle diameters with the desired efficiency are in filter classes called EPA, HEPA and ULPA.

Gas Phase Filtration

They are air filters that protect the environment, process and working personnel by controlling various gas phase pollutants (corrosive, toxic, irritating and odour effective) in mechanical ventilation systems of industrial and commercial areas.

Mixing Cells and Dampers

Fresh air damper and synthetic filter elements are used within the air handling unit structure. Dampers are selected according to a maximum 6m/sec air velocity.

Exhaust Cell

The exhaust chamber with indoor air and exhaust air damper is necessary for the operating principle of the air handling unit.

Silencer

For those who think about how the air handling unit works, we can talk about the importance of using a silencer. Silencers usually consist of 10-20 cm plates. It has the characteristics of other cells in terms of construction.

Heat Recovery Unit

There must be a heat recovery unit in the air handling unit structure. Economic use is provided thanks to aluminium plate and drum heat recovery systems.

Different systems are determined for each space as air handling unit working conditions. Air handling units provide comfort by keeping the humidity and temperature of the indoor air constant under the desired conditions. Air handling unit types perform heating, cooling, dehumidification, and humidification processes, which are the four known thermodynamic air conditioning functions. Whatever your needs are, you need to choose the features of the system according to your needs. It is important to get professional support for the air handling unit specific to your space.