In modern buildings, ensuring proper air circulation, temperature control, and indoor air quality is crucial for comfort, productivity, and safety. Air Handling Units (AHUs) play a central role in heating, ventilation, and air conditioning (HVAC) systems by conditioning and distributing air throughout buildings. Whether in commercial complexes, hospitals, hotels, or industrial facilities, AHUs are indispensable for creating a healthy and comfortable indoor environment. Refcon Engineers, a leading Air Handling Unit manufacturer, provides efficient and reliable AHUs tailored for various applications. In this blog we explained how exactly does an Air Handling Unit work? Let’s break it down in simple terms, step by step.
What is an Air Handling Unit?
An Air Handling Unit (AHU) is a large device used in heating, ventilation, and air conditioning (HVAC) systems to regulate and circulate air inside buildings. This process keeps the environment inside comfortable, safe, and healthy for everyone. AHUs are usually installed on rooftops, in basements, or in mechanical rooms.Air handling unit HSN code 8415 is used in GST and invoices for Air Handling Unit (AHU) They may work alone or in combination with chillers, boilers, and ventilation systems, depending on the size and type of the building.
There are various types of Ahu Units available like floor mounted air handling unit, double skin air handling unit, single skin air handling unit, custom air handling unit, commercial air handling unit. Refcon Engineers leading industrial air handling unit manufacturers, offer high quality, precise ahu units at affordable prices.
Air Handling Unit (AHU) Working Principle
The journey of air inside an AHU happens in a well-structured sequence. Here’s how it works in detail:
Air Intake – Bringing Fresh Air Inside
- The process begins when the AHU pulls in air from two sources: fresh outside air and recirculated indoor air.
- The combination of both is carefully balanced through louvers and dampers. This helps maintain energy efficiency while ensuring indoor spaces never feel suffocating.
- By allowing a portion of fresh air continuously, AHUs keep the indoor environment lively and oxygen-rich.
Filtration – Cleaning the Air
- Once air enters the AHU, the first line of defense is the air filters.
- These filters trap dust, pollen, bacteria, smoke particles, and other airborne contaminants.
- Advanced systems may use multiple layers of filters (like pre-filters and fine filters) to ensure maximum cleanliness. This step is especially critical in hospitals, labs, and clean rooms where air quality is non-negotiable.
Cooling and Heating Coils – Conditioning the Air
- After filtration, the air moves through a set of coils. Depending on the requirement, these coils are supplied with chilled water (for cooling) or hot water/steam (for heating).
- On a hot summer day, the chilled water coils cool down the air, while in cold winters, heating coils warm it up.
- This ensures that the air delivered to rooms always feels comfortable, regardless of outside weather.
Humidity Control – Balancing Moisture Levels
- Comfort is not just about temperature; it’s also about the right level of moisture.
- If the air is too dry, humidifiers inside the AHU add moisture. If it’s too damp, dehumidification systems remove excess humidity.
- This balance prevents dryness in skin and eyes, reduces allergies, and keeps wooden furniture, electronics, and other sensitive equipment safe.
Blower/Fan Section – Pushing the Air Forward
- Powerful blowers or fans installed inside the AHU now take charge of moving this conditioned air.
- They push the air into the network of ducts, ensuring it reaches every corner of the building—from the top floor of an office tower to the basement of a shopping mall.
- The design of these fans ensures even distribution so that no area feels stuffy or left out.
Air Distribution – Delivering Comfort Everywhere
- The ductwork connected to the AHU acts like the blood vessels of the system, carrying fresh and conditioned air to different rooms.
- At the same time, return air ducts bring some portion of used air back into the AHU to be filtered and conditioned again.
- This cycle not only saves energy but also keeps the indoor environment consistently fresh.
Exhaust System – Releasing Stale Air
- Not all indoor air is reused. A certain percentage of stale air is expelled outside through the exhaust system.
- This prevents the buildup of carbon dioxide, odors, and contaminants inside the building.
- By balancing supply air, return air, and exhaust, the AHU maintains both freshness and efficiency.
Air Handling Unit Diagram
AHU Unit works like the lungs of the building—drawing in air, cleaning it, adjusting the temperature and humidity, and then distributing it to every corner.
To understand it better, let’s take a look at the diagram of an Air Handling Unit (AHU) and see how each part plays its role step by step.
Types of AHU Unit
- Modular AHU: A Modular AHU is designed with separate sections or modules that perform specific functions such as filtration, heating/cooling, and humidification. These units are highly flexible, allowing easy transport, installation, and maintenance. The modular design also makes it possible to expand the system in the future as building requirements grow. Commonly used in large commercial buildings, hospitals, and office complexes, modular AHUs provide reliable air handling while allowing customization for various applications.
- Compact or Small AHU: Compact AHUs are ideal for areas where space is limited, such as small offices, classrooms, or retail spaces. Despite their smaller footprint, they provide complete air handling capabilities, including air filtration, heating or cooling, and humidity control. Often pre-assembled for easy installation, compact AHUs are a convenient solution for facilities that require efficient air conditioning without occupying significant space.
- Packaged AHU System: A Packaged AHU integrates all components into a single, self-contained unit, usually installed on rooftops or outdoors. This configuration saves indoor space and simplifies installation. Packaged AHUs are widely used in hotels, office buildings, and industrial facilities. They often come with advanced features like heat recovery systems, digital controls, and energy-efficient components, making them suitable for large-scale applications requiring consistent airflow and climate control.
- Custom or Special-Purpose AHU: Custom AHUs are specially designed to meet the unique requirements of sensitive environments such as cleanrooms, hospitals, pharmaceutical labs, and industrial processes. These units can incorporate high-efficiency filters, precise temperature and humidity control systems, and corrosion-resistant coatings for chemical environments. Manufacturers like Refcon Engineers specialize in creating these custom solutions, ensuring optimal performance, energy efficiency, and compliance with specific industry standards.
- Rooftop Air Handling Unit: Rooftop AHUs are installed on building rooftops to save valuable indoor space while providing conditioned air to the entire building or selected zones. These units are connected to duct systems that distribute air efficiently throughout commercial buildings, large retail spaces, and multi-story facilities. Rooftop AHUs are designed to withstand weather conditions and often include robust insulation and weatherproof casings.
- Centralized AHU: A Centralized AHU serves as a single air handling unit for an entire building or multiple zones. By managing air quality, temperature, and humidity from a central location, these units ensure uniform indoor conditions throughout the facility. When combined with variable air volume (VAV) systems, centralized AHUs offer high energy efficiency, making them ideal for large commercial complexes, hospitals, and industrial plants where consistent air quality and comfort are critical.
Conclusion:
An Air Handling Unit (AHU) is a vital device that cleans, cools, or heats air and supplies it throughout a building or industry, ensuring a comfortable and healthy environment. Proper AHU design and maintenance saves energy and extends system life. Refcon Engineers focuses on reliability, the latest technology, and customer satisfaction with its high-quality AHUs. If you are looking for a durable and efficient AHU solution for your project, Refcon Engineers is a trusted choice.
