Since 1939, Hudson Products has designed and manufactured air-cooled heat exchanger equipment to serve the oil, gas, refining, chemical, LNG and power generation industries. Through our commitment to innovation, Hudson has remained the world leader in this field for over 75 years.  All air-cooled heat exchangers are custom engineered by our experienced heat transfer and mechanical engineers in accordance with customer requirements and industry standards such as ASME, AWS, API 661 and ISO 13706.

Typical Applications

Fin-Fan® air-cooled heat exchangers are used to reject heat in a wide variety of applications. 

Here are just a few examples:

  • LNG: refrigerant condensing and sub-cooling, lube-oil cooling
  • Refining: reactor loop cooling, tower overhead condensing, product run-down cooling
  • Natural gas processing plants: tower overhead condensing, propane refrigerant condensing
  • Natural gas transmission: compressor inter-stage and after cooling
  • Chemicals: reactor cooling, condensing, product run-down cooling, packaged machinery cooling
  • Geothermal Power: Organic Rankin Cycle refrigerant condensing, steam turbine exhaust cooling, auxiliary cooling
  • Combined Cycle Power: auxiliary cooling, turbine exhaust cooling
  • Oil sands: glycol and water cooling for SAGD extraction


Individual bay sizes for shop assembled units up 70 feet x 22 feet and fan sizes from 2 feet to 18 feet.  Field erected bay sizes up to 70 feet by 54 feet with fan sizes up to 36 feet.

Components of Air-cooled heat exchangers

Fin-Fan® air-cooled heat exchangers consist of the following components:

  • One or more finned tube bundles of heat transfer surface.
  • Except in natural draft applications, an axial flow fan and drive system
  • A plenum between the bundle or bundles and the axial flow fan.
  • If grade mounted, a support structure high enough to allow air to enter beneath the air-cooled heat exchanger at a reasonable rate.
  • Optional header and fan maintenance walkways with ladders to grade.
  • Optional louvers for process outlet temperature control.
  • Optional recirculation ducts and chambers for protection against freezing or solidification of high pour point fluids in cold weather.
  • Hail guards
  • Optional variable pitch fan hub for temperature control and power savings.

Hudson Provides a Range of Customized Specifications

  • Bundle Configuration(Horizontal/Vertical/Sloped)
  • Fan Configuration (Horizontal/Vertical)
  • Draft Type (Forced/Induced)
  • Temperature Control (Variable Speed Fans/ Variable Pitch Fans/Air Recirculation/Louvers)
  • Construction (Shop/Field)
  • Fan Drive (Engine/Electric)
  • Proprietary winterization designs for low ambient temperatures and/or viscous or high pour-point fluids
  • Ultra-high pressure serpentine coil design

Only Hudson:

  • Possesses both heat transfer and fan engineering expertise to ensure customers get the best engineering solution; in addition to our Tuf-Lite® fans Hudson also manufactures Cofimco aluminum fans 
  • Provides Hy-Fin Extruded and Extruded Serrated finned tubing manufactured using our proprietary extruded finning process to the highest quality standards in the industry; and we ensure the very best aluminum-to-tube bond by thermally testing the finished fin-tube. 
  • Manufactures our own long-life self-aligning fan bearings and   shafts specifically designed for critical services.
  • Brings 75+ years of expertise and know-how to air cooled heat exchanger


Induced Draft
Forced Draft
Large Fan Field Erected
Induced Draft

The induced draft configuration positions the fans above the exchanger bundle. High velocity hot air exhaust reduces the risk of hot air recirculation, and plenums protect the exchanger bundle from the elements. Induced draft exchangers are well suited for lower process temperatures and for applications  where hot air recirculation is a concern.

Forced Draft

In the forced draft configuration, fans and mechanical components are positioned below the exchanger bundle. Because the fans are in the cool air stream, horsepower requirements are slightly lower and maintenance personnel are protected from high exit air temperatures. Forced draft exchangers are well suited for high-temperature service.


Air-cooled heat exchangers in very cold climates and/or involving viscous or high pour-point fluids may require winterization for freeze protection and process temperature control. To prevent process fluids from freezing and to protect the exchanger, the exchanger is equipped with automatic louvers and recirculation chambers to mix warm exhaust air with cold inlet air and plenum heaters for start-up.

Large Fan Field Erected

Our large fan field erected units are available in bay sizes up to 70 feet by 54 feet and fan diameters up to 36 feet.  Our modular design and construction expertise allows for fast and dependable field erection.  Benefits of the large fan design include:

  • Fewer fans, drives and power transmission sets to install and maintain
  • Simplified foundations with fewer support columns
  • With a velocity recovery stack installed, improved efficiency and less risk of hot air recirculation
  • Overall reduced installation time and cost for large banks of coolers

First introduced in 1949, the Combin-aire® is a water-assisted air-cooled heat exchanger. In Combin-aire cooling, high temperature ambient air is first pre-cooled by direct contact with water. Then the cooled air flows through a demister before contacting the fin-tube elements.  Cooling with Combin-aire overcomes the limitation of high ambient temperatures while minimizing water use and with no pluming.


Fin Types
Header Options
Mechanical Components
Fin Types
Hudson Hy-Fin® Extruded Fins: 

Extruded fins are applied by forming the fins from the metal of a tubular aluminum sleeve into which the fluid handling tube has been inserted. The extruded finning machine literally squeezes the fins out in a close spiral shape from the material of the aluminum sleeve. This extrusion raises the fins to their required height, leaving a substantial thickness of aluminum totally encasing the fluid handling tube. This design offers excellent resistance to corrosion as the aluminum fin completely encloses the metal of the tube and provides the best bond between fin and process tube.

Hudson Hy-Fin® Extruded Serrated Fins:

Extruded Serrated fins are formed by taking the standard extruded finned tubes and cutting longitudinal serrations along the entire length of the finned tubes. The serrations improve the heat transfer rate and allow for smaller footprint designs.

Embedded Fins: 

Embedded fins are applied by first plowing or rolling a continuous spiraling groove into the outer surface of the tube. A strip of fin material is then wound on edge into this groove followed by a mechanical process that either peens or rolls the tube material against the inserted fin. The integrity of this process can only be verified by a fin pull test. Preferred design for cyclical temperatures and high temperature service.

Wrap-On Fins: 

Wrap-on fins are applied by feeding a thin strip of heat conducting metal (usually aluminum) into a machine which first forms a small “foot” at one edge of the strip (L-Base). The strip is wound tightly around the tube and retained by staples at both ends of the tube. Most economical option and offers some protection from corrosion. Not recommended for severe service.

Header Options
Plug-Box Headers

The plug box header consists of tube sheet, plug sheet, top, bottom, and end plates welded together to form the header. Holes are drilled and grooved in the tube sheet so that the tubes can be rolled in place. Holes are drilled and threaded in the plug sheet opposite each tube to allow access to the tubes. Partitions are welded in the headers to establish the tube-side flow pattern, which generates suitable velocities in as near countercurrent flow as possible for maximum mean temperature difference. Partitions and stiffeners (partitions with flow openings) also act as structural stays. Horizontally split headers may be required to accommodate differential tube expansion in services having high fluid temperature differences per pass.

Removable Cover Headers

Bolted removable cover plates are used for improved access to headers in severe fouling services or where complete access to the inside of the header boxed is desired. The removable cover header is constructed similarly to the plug box header except that a flanged and gasketed solid cover plate replaces the plug sheet. Cover plate headers are limited to approximately 400 psi in design pressure.

Pipe and U-Bend Headers

Pipe and U-bend headers are utilized for very high pressure applications. These designs are more expensive and difficult to access the tubes, but necessary for design pressures above approximately 5000 psi.

Tube-to-Tubesheet Joints

Standard is a rolled tube-to-tubesheet joint, but seal-welded and strength-welded construction is also available.

Mechanical Components

The air moving device for a Fin-Fan® air-cooled heat exchanger is commonly an axial flow, propeller type fan that either forces the air across the bundles (forced draft) or pulls it across (induced draft). To provide redundancy in case a mechanical unit falls and to provide the basic control achievable by running one fan or two, a bundle or set of bundles is usually provided with two fans. Depending on design requirements and customer preference, a Fin-Fan® may be supplied with Hudson Tuf-Lite® fiberglass fans or Cofimco aluminum fans.


Fans are typically driven by electric motors according to customer specifications. Speed reduction is typically accomplished with high-torque positive type belt drives, which uses sprockets that mesh with the timing belt cogs. Also available for high horsepower applications or according to customer preference, are right angle gear drives. Bearings for fan shafts are specially made for Hudson for severe duty use in Fin-Fan® exchangers.


Typical accessories may include:

  • Ladders and maintenance access platforms.
  • Steam coils for auxiliary heating
  • Louvers for air flow control
  • Louver actuators
  • Auto variable pitch fans
  • Vibration switches or monitors
  • Bug screens
  • Special access doors
  • Hail guards
  • Header personnel guards
  • Ultra high Pressure serpentine coil designs