Views: 0 Author: Site Editor Publish Time: 2026-02-13 Origin: Site
Air Handling Units (AHUs) are designed to condition air for comfort, process, or data-critical environments, and they can be equipped with a variety of heating and cooling methods depending on energy sources, system design, and application requirements.
Most common cooling method for medium to large AHUs
Uses chilled water supplied from a central chiller plant
Can achieve precise temperature control
Suitable for commercial buildings, data centers, and industrial processes
AHU contains refrigerant coils connected to a condenser/compressor system
Often used where a central chiller is unavailable
Suitable for small to medium AHUs
Can include multiple stages for high-precision temperature control
Uses water evaporation to pre-cool incoming air
Reduces cooling load on downstream coils or chillers
Effective in dry climates and energy-efficient designs
AHUs can be combined with RDHx, dry cooler, or heat exchanger loops
Captures free cooling from outdoor air or other systems
Reduces or eliminates mechanical cooling in mild climates
Most widely used heating option
Hot water from a boiler or heat pump passes through AHU coils
Provides even, controllable heat across large airflows
Uses saturated or superheated steam from a central boiler
Common in industrial, hospital, or district heating applications
Can achieve high heating capacity in compact coil size
Resistance heating elements integrated in AHU
Suitable for small to medium AHUs or backup heating
Fast response, no boiler or hot water system required
Typically used in data centers, offices, or retrofits
Combines multiple sources, e.g., hot water + electric backup
Provides flexibility and redundancy
AHUs can be configured with both heating and cooling coils in series or parallel
Series arrangement: air passes through cooling coil first, then heating coil (for dehumidification control)
Parallel arrangement: separate supply air streams with mixing dampers for energy optimization
| Factor | Consideration |
|---|---|
| Airflow volume | Determines coil size and type |
| Space constraints | DX coils are compact; chilled water coils may require larger AHU |
| Available utilities | Boilers, chillers, heat pumps, electricity |
| Temperature and humidity control | Steam coils provide fast heating; chilled water allows precise cooling |
| Energy efficiency | Free cooling, heat recovery, and high-efficiency coils reduce operational cost |
| Maintenance | Steam coils require blowdown/inspection; DX coils need refrigerant servicing |
AHUs are highly flexible in terms of heating and cooling options, making them adaptable for applications ranging from office buildings and hospitals to data centers and industrial plants.
Cooling: Chilled water, DX coils, adiabatic pre-cooling, heat recovery/free cooling
Heating: Hot water coils, steam coils, electric heaters, or hybrid systems
The final choice depends on available utilities, energy efficiency targets, space constraints, and operational requirements.
