What is an Air-Cooled Heat Exchanger (ACHE)? Working Principle & Types | CSTHEATEXCHANGER

In petrochemical refineries, power generation plants, chemical complexes, and natural gas pipelines, water availability is often restricted by environmental regulations or geography. Air-Cooled Heat Exchangers (ACHE) provide high-capacity, 100% water-free thermal rejection directly to atmospheric air.

At CSTHEATEXCHANGER, we engineer and manufacture custom Air-Cooled Heat Exchangers (ACHE / Fin-Fan Coolers) compliant with API 661 and ASME Section VIII standards. Below, our thermal engineers explain how ACHEs operate and how to choose between forced-draft and induced-draft designs.

1. How an Air-Cooled Heat Exchanger (ACHE) Works

An ACHE operates via external forced-convection heat transfer:

1. Fluid Flow: Hot process fluid (hydrocarbon vapor, steam, water/glycol, thermal oil) flows inside finned tubes under pressure.

2. Air Flow: Large electric motor-driven axial fans blow or pull high volumes of ambient air across the outside of the finned bundle.

3. Direct Thermal Rejection: Heat conducts from the fluid through the tube wall and extended fins into the passing airstream, rejecting heat directly to the atmosphere with zero water loss and zero chemical treatment.

2. Forced Draft vs. Induced Draft Configurations

┌────────────────────────────────────────────────────────────────────────┐
│                   FORCED DRAFT VS. INDUCED DRAFT ACHE                  │
├─────────────────┬──────────────────────────────────────────────────────┤
│ Forced Draft    │ Fans located BELOW tube bundle. Pushes air upward.   │
│ (Most Common)   │ • Easier ground-level fan and motor maintenance.     │
│                 │ • Handles higher fluid temperatures safely.          │
├─────────────────┼──────────────────────────────────────────────────────┤
│ Induced Draft   │ Fans located ABOVE tube bundle. Pulls air through.   │
│                 │ • Superior air distribution across entire face.      │
│                 │ • Eliminates hot air recirculation & rain damage.    │
└─────────────────┴──────────────────────────────────────────────────────┘

3. Contact CSTHEATEXCHANGER for Custom ACHE Sizing

Eliminate cooling water constraints with utility-grade air-cooled heat exchangers. Contact CSTHEATEXCHANGER today for API 661 engineering calculations and datasheets.

• Website: www.cstheatexchanger.com

• Email: info@cstheatexchanger.com

• Phone / WhatsApp: +86 0519 8878 2189 / +86 181 3659 3690

• Manufacturer: Changzhou Vrcoolertech Refrigeration Co., Ltd., Changzhou, Jiangsu, China