Heat Exchanger

Heat exchanger, abbreviated as HE or HEX, is a device used to transer heat from one medium to another at different temperatures.  The heat transfer can be air or a liquid such as water or oil.

A heat exchanger has many functions.  They are critical to the process industries as they used to condense, heat, cool, or chill a fluid.  It also can be used to change the phase of a fluid (liquid to vapor or vapor to liquid) like a boiler.  Heat exchangers can be a direct contact HEX or an indirect contact type HEX. 

In a direct contact heat exchanger, heat transfer continuously occurs by the mixing of two process streams.  An example of this is a cooling tower, commonly found in power plants where a stream of hot air is consistently mixed with cooler water.  The water cools the hot air and exits the top of the cooling tower.  Warm water exits the bottom of the tower, is recollected, cooled and used again. 

An indirect contact type heat exchanger transfers heat by maintaining a separation between the two process streams.  Examples of an indirect contact type HEX are Shell and Tube Heat Exchangers and Air Cooled Heat Exchanger (also known as a fin-fan)


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Heat Exchanger Types

  • Extended surface
    • Plate fin
    • Tube fin
      • Heat pipe wall
      • Ordinary seperating wall
  • Plate
    • Coil
    • Plate
      • Brazed
      • Gasketed
      • Welded
    • Printed circuit
    • Spiral
  • Tubular
    • Double pipe
    • Pipe coils
    • Shell and Tube
      • Cross flow to tubes
      • Parallel flow to tubes
    • Spiral tube
  • Regenerative
    • Fixed matrix
    • Rotating hood
    • Rotary


Heat Exchanger Standards

API Standards

  • API Std 530 - Calculation of Heater-tube Thickness in Petroleum Refineries
  • API Std 660 - Shell-and-Tube Heat Exchangers
  • API Std 661 - Petroleum, Petrochemical, and Natural Gas Industries—Air-cooled Heat Exchangers

ASTM Standards

  • ASTM B395 / B395M - Standard Specification for U-Bend Seamless Copper and Copper Alloy Heat Exchanger and Condenser Tubes
  • ASTM B543 / B543M - Standard Specification for Welded Copper and Copper-Alloy Heat Exchanger Tube
  • ASTM B743 - Standard Specification for Seamless Copper Tube in Coils
  • ASTM B903 - Standard Specification for Seamless Copper Heat Exchanger Tubes With Internal Enhancement
  • ASTM B919 - Standard Specification for Welded Copper Heat Exchanger Tubes With Internal Enhancement
  • ASTM B944 - Standard Specification for Copper-Beryllium Welded Heat Exchanger and Condenser Tube (UNS No. C17510)
  • ASTM B956 / B956M - Standard Specification for Welded Copper and Copper-Alloy Condenser and Heat Exchanger Tubes with Integral Fins
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Fin-fan Heat Exchanger
Heat Exchanger Types
Shell and Tube Heat Exchanger
Shell and Tube Heat Exchanger TEMA Designation

Tags: Equations for Heat Exchangers