As a facility management professional, it is essential to have a comprehensive understanding of the different types of air handler units (AHU) used in commercial HVAC systems. Aims to provide a comparative analysis of three commonly used air handler units: chilled water air handler unit, package air handler unit, and direct expansion (DX) air handler unit.
By exploring their unique characteristics, working principles, and applications, can gain valuable insights into their suitability for various HVAC system configurations.
Chilled Water Air Handler Units
A chilled water air handler unit is a type of HVAC system that uses chilled water as a medium to cool and dehumidify the air. It consists of a cooling coil, a supply fan, filters, dampers, and a heating coil (optional). The chilled water coil removes heat from the air, and the supply fan circulates the conditioned air throughout the building.
Chilled water AHU maintenance:
- Regularly clean or replace air filters to ensure optimal air quality and airflow.
- Inspect and clean the cooling coil to remove any dirt, debris, or microbial growth that may obstruct heat transfer.
- Check and adjust belt tensions, lubricate bearings, and ensure proper fan operation.
- Monitor and maintain the chilled water system, including pumps, valves, and controls.
- Periodically inspect and test the air handler unit’s overall performance and energy efficiency.
Direct Expansion (DX) Air Handler Units
DX air handler unit is a self-contained HVAC system commonly used in commercial buildings
A direct expansion (DX) air handler unit, also known as a rooftop unit (RTU), is a self-contained HVAC system commonly used in commercial buildings. It uses refrigerant as the cooling medium and includes a compressor, evaporator coil, condenser coil, supply fan, filters, and optional heating elements. DX air handlers provide both cooling and heating functions.
DX AHU maintenance:
- Regularly clean or replace air filters to ensure proper airflow and prevent dust buildup.
- Inspect and clean the evaporator and condenser coils to maintain efficient heat transfer.
- Check and clean the condensate drain line to prevent clogs and potential water damage.
- Verify the refrigerant charge and inspect for any leaks.
- Monitor and maintain the compressor, fans, and electrical components.
- Periodically assess the overall performance and energy efficiency.
Package Air Handler Unit
A package air handler unit is a self-contained DX HVAC system typically installed outdoors or on the rooftop of a building. It combines heating, cooling, and ventilation functions into a single unit. The package air handler includes a heating and cooling coil, supply fan, filters, dampers, and sometimes a heat recovery system.
Package AHU maintenance:
- Regularly clean or replace air filters for proper air quality and system performance.
- Inspect and clean the heating and cooling coils to maintain efficient heat transfer.
- Check and clean the condensate drain line to prevent clogs and water damage.
- Monitor and maintain the fans, belts, bearings, and electrical components.
- Ensure proper operation of the control system and safety devices.
- Periodically assess the overall performance and energy efficiency.
How Help With Air Handler Unit Management
In all cases, regular preventive maintenance is crucial to ensure the optimal operation, energy efficiency, and longevity of the air handler units. It is recommended to follow manufacturer guidelines and consult qualified technicians for specific maintenance procedures. WTI Pure Air Control Services has been assessing, cleaning, and restoring AHUs since 1985! All in one, solutions for managing air handler units in commercial and institutional facilities. These include HVAC Assessments, HVAC Steam Cleaning, and HVAC Restoration.
Understanding the differences between chilled water air handler units, package air handler units, and DX air handler units is crucial for mechanical engineers and HVAC maintenance professionals. Each type has its own advantages and is suitable for specific applications. By considering factors such as system size, efficiency requirements, and control capabilities, one can make informed decisions while designing and maintaining commercial HVAC systems.
