The following Wiki entry provides a comprehensive overview of air handlers. In the context of mobile heating and cooling systems, they distribute the generated heat or cold efficiently and safely on construction sites, in industrial halls, or in event tents.
Table of Contents
What Is an Air Handler?
It is a central component in the heating, ventilation, and air conditioning (HVAC) industry, whose main task is to condition and circulate air. It is a large, box-shaped device that contains various air treatment modules, including fans, heating and cooling coils, filters, and dampers.
What Are Air Handlers Used For?
They regulate the air quality, temperature, and humidity in a building and distribute the treated air via a duct system (or directly) to the space being served.
How Do Air Handlers Work?
The operation is based on a sequential process in which the air passes through various treatment stages before being delivered into the room.
- Air Intake and Mixing: It draws in either outside air (fresh air) and/or exhaust air (return air) from the building. In a mixing chamber, the ratio of outside and return air is controlled via dampers to efficiently achieve the desired supply air temperature and ensure indoor air quality.
- Filtration: The intake air is passed through filters to remove dust, pollen, dirt particles, and other pollutants. This not only protects the downstream components but also ensures clean supply air.
- Conditioning (Heating/Cooling): The filtered air flows over heat exchanger coils. These coils can be operated with hot water, steam, cold water, or a refrigerant (glycol-water mixture in mobile applications) to heat or cool the air.
- Humidity Control: Depending on the requirements, the air handler can also be used for dehumidification (by overcooling to create condensation) or for humidification of the air.
- Air Circulation: A powerful fan (blower) draws the treated air through the components and pushes it into the duct system (or directly) into the area to be supplied.
Components of an Air Handler
A device consists of several components, which can vary depending on the application:
| Component | Function |
|---|---|
| Fan | Circulates the air through the unit and the duct system; often designed as a centrifugal fan. |
| Filter | Removes particles from the air, ranging from simple panel filters to HEPA filters. |
| Heating and Cooling Coils | Heat exchangers that regulate the air temperature using hot water/steam or cold water/refrigerant. |
| Mixing Chamber | Regulates the ratio of outside air and return air for temperature and air quality control. |
| Silencer | Reduces the operating noise generated by the fan. |
| Vibration Isolators | Flexible connections and springs to prevent the transmission of fan vibrations to the building. |
What Types of Air Handlers Are There?
They are classified according to various criteria, with the application and design being the most common distinguishing features:
- Terminal Units / Fan Coils: Small devices for local use, often containing only a filter, a coil, and a fan.
- Makeup Air Units (MAU) / Fresh Air Handling Units (FAHU): Units that condition 100% outside air and do not use return air.
- Rooftop Units (RTU) / Packaged Units (PU): Devices designed for outdoor use, typically on roofs.
- Mobile Air Handlers: Specially designed for temporary use, often compact and robust units that can be quickly connected to mobile heating or cooling systems.
Types of Mobile Air Handlers
They are often designed as air recirculation coolers or ventilation systems and are characterized by high performance (e.g., 50 kW to 150 kW) and easy transportability.
| MW24 Example | Main Function | Medium | Power (Example) |
|---|---|---|---|
| Air Handler Ventilation System | Heating and air distribution | 30% water-glycol mixture | 75 kW / 150 kW |
| Air Handler Recirculation Cooler | Cooling and air distribution | 30% water-glycol mixture | 50 kW / 70 kW |
These mobile units typically use large-diameter hot air hoses (e.g., 500 mm) to distribute the conditioned air evenly over a distance of up to 30 meters.
What Do Air Handlers Have to Do with Mobile Heating and Cooling?
It plays a crucial role in mobile heating and cooling technology. While a mobile heating unit generates the heat, the air handler is the link that transfers this heat into the air and distributes it throughout the room.
Uses in the Mobile Sector
Mobile devices are used in situations where fast, flexible, and powerful temperature control is required. The applications are diverse:
- Construction Site Heating: Heating of building shells to accelerate construction processes or prevent frost damage.
- Industrial and Warehouse Halls: Efficient temperature regulation in large, open spaces.
- Event Venues: Controlled air circulation and pleasant temperatures in marquees, temporary halls, or at events.
- Special Applications: Optimal operating conditions in server rooms (cooling) or controlled air in healthcare facilities.
The devices from Mobile Wärme 24 are indirect systems. This means they do not contain their own combustion chamber but function as heat exchangers. They are connected via hoses to an external mobile heating unit (or cooling unit), which supplies the hot (or cold) water-glycol mixture. The air handler then blows the room air over the coils to absorb the heat and release it into the room. This ensures clean and safe heating, as no combustion gases enter the space to be heated.
In the field of mobile heating and cooling, air handlers are therefore often used as indirect systems on construction sites, in industry, at events, or for special applications.
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Sources:
The Engineering Mindset. (seen on Oct 10, 2025). Air Handling Units Explained.