WHAT IS THE MAIN FUNCTION OF AHU?

Air handling units (AHUs) are essential components of heating, ventilation, and air conditioning (HVAC) systems in various buildings, ensuring occupants' comfort and indoor air quality. Understanding the main functions of an AHU is crucial for comprehending its role in maintaining a conducive indoor environment.

Functions of an AHU

1. Air Circulation:

   • AHUs are responsible for circulating air throughout a building, ensuring proper ventilation and preventing air stagnation.
   • They draw in fresh outdoor air, filter it to remove contaminants, and distribute it to various rooms through a network of ducts.
   • Simultaneously, they exhaust stale indoor air, removing pollutants, odors, and excess moisture.

2. Temperature Control:

   • AHUs play a crucial role in maintaining a comfortable indoor temperature.
   • They can heat or cool the air passing through them, using various methods such as hot water coils, electric heating elements, or refrigerant coils.
   • By regulating the temperature of the air, AHUs ensure a pleasant and productive indoor environment.

3. Humidity Control:

   • AHUs help control indoor humidity levels, preventing excessive dryness or moisture.
   • In humid climates, AHUs dehumidify the air by removing excess moisture through condensation or desiccant wheels.
   • In dry climates, they humidify the air by adding moisture through steam generators or water spray nozzles.

4. Air Filtration:

   • AHUs are equipped with air filters to remove particulate matter, dust, pollen, and other airborne contaminants from the air.
   • These filters improve indoor air quality, reducing the risk of respiratory issues and allergic reactions among occupants.
   • Different types of filters are available, ranging from basic dust filters to high-efficiency particulate air (HEPA) filters, depending on the required level of filtration.

5. Ventilation:

   • AHUs provide ventilation by introducing fresh outdoor air into the building while exhausting stale indoor air.
   • Adequate ventilation is essential for maintaining good indoor air quality, diluting pollutants, and preventing the buildup of harmful gases.
   • AHUs can be equipped with energy recovery ventilators (ERVs) or heat recovery ventilators (HRVs) to minimize energy losses during ventilation.

Conclusion

Air handling units (AHUs) perform multifaceted functions that are vital for maintaining a comfortable and healthy indoor environment. They circulate air, control temperature and humidity, filter the air, and provide ventilation, ensuring the overall well-being of occupants. Proper selection, installation, and maintenance of AHUs are crucial for achieving optimal performance and meeting the specific requirements of different buildings.

Frequently Asked Questions

1. What are the different types of AHUs?

   • AHUs can be classified based on their configuration, functionality, and application. Common types include rooftop AHUs, horizontal AHUs, vertical AHUs, and dedicated outdoor air system (DOAS) AHUs.

2. How is the capacity of an AHU determined?

   • The capacity of an AHU is typically measured in cubic feet per minute (CFM) of air that it can handle. Factors such as the size of the building, number of occupants, and desired indoor conditions influence the required capacity.

3. What are the energy-saving features available in AHUs?

   • AHUs can incorporate energy-efficient technologies such as variable-speed fans, efficient motors, heat recovery wheels, and economizers. These features reduce energy consumption and operating costs.

4. How often should AHUs be serviced or maintained?

   • Regular maintenance is essential for ensuring optimal performance and longevity of AHUs. The frequency of maintenance depends on the operating conditions, but it is generally recommended to conduct routine inspections and maintenance every 3-6 months.

5. What are the signs that an AHU needs to be replaced?

   • Reduced airflow, increased noise levels, higher energy consumption, and inability to maintain desired temperature and humidity levels are common indicators that an AHU may need to be replaced. Additionally, age, deterioration, and lack of spare parts can also necessitate replacement.