Air-Cooled Heat Exchangers (ACHEs) in HVAC & Industrial Cooling
Air-cooled heat exchangers (ACHEs) are widely used in HVAC systems and industrial cooling applications where water conservation, maintenance simplicity, and environmental regulations are key concerns. Unlike water-cooled systems, ACHEs rely on ambient air to dissipate heat, making them ideal for dry climates or locations with water restrictions.
Key Components
| Component | Function |
| Finned Tube Bundles | Maximize surface area for heat transfer. |
| Axial/Centrifugal Fans | Provide airflow (forced or induced draft). |
| Headers & Manifolds | Distribute fluid into tubes. |
| Plenum Chamber | Ensures uniform airflow across tubes. |
| VFDs/Louvers | Adjust fan speed/airflow for temperature control. |
| Support Frame | Structural stability for outdoor installation. |
Types of ACHEs in HVAC & Industrial Cooling
A. Based on Application
- HVAC Condensers
- Used in air conditioning & refrigeration (e.g., rooftop units, chillers).
- Typically use refrigerants (R-134a, R-410A, ammonia).
- Industrial Process Coolers
- Cool machinery, hydraulics, compressors, and data centers.
- Handle water, oils, glycol mixtures, or chemicals.
- Dry Coolers
- Closed-loop systems cooling water/glycol without evaporation.
- Used in data centres, breweries, and power plants.
- Fluid Coolers (Hybrid)
- Combine air + minimal water spray for adiabatic cooling.
B. Based on Fan Design
- Forced Draft (Fans below tubes) → Easier maintenance.
- Induced Draft (Fans above tubes) → Better airflow distribution.
Advantages in HVAC & Industrial Cooling
No Water Consumption – Ideal for arid regions.
Lower Maintenance – No scaling, algae, or water treatment needed.
Energy Efficiency – VFD fans optimize power usage.
Compact & Modular – Can be roof-mounted or skid-mounted. Environmentally Friendly – No water discharge or chemical treatment.
Common HVAC & Industrial Applications
HVAC Systems
- Chiller condensers (replacing cooling towers).
- Rooftop AC units.
- Heat pump systems.
Industrial Cooling
- Compressed air aftercoolers.
- Hydraulic oil cooling.
- Data centre cooling (dry coolers).
- Plastic injection moulding machines.
- Power plant auxiliary cooling.
Design Considerations
- Ambient Temperature (critical for sizing).
- Airflow Control (VFDs for energy savings).
- Material Selection (copper/aluminum fins for corrosion resistance).
- Noise Restrictions (low-noise fan designs for urban areas).