Heat Exchanger Design, Heat Exchanger Sizing

Design Tips         
Thermal design and sizing of heat exchangers is often relegated to senior engineers because of the complexity of the task and the number of parameters involved.  A sound foundation in process engineering and familiarity with the mechanical aspects of heat exchangers ensures successful designs that satisfy the process requirements for years without failure.
We aim to provide some helfull design guidelines and tips to help engineers engaged in the thermal design and sizing of heat exchangers.

Outlines the different type of heat transfer equipment such as Shell-and-Tube heat exchangers, Plate-and-Frame or Compact heat exchangers and Air-cooled heat exchangers.  Also provides criteria for heat exchanger type selection.

Outlines the construction details of shell-and-tube heat exchangers.  Details such as the shell, tubes, tubesheets, baffles, tie rods and spacers, pass partitions and channels are discussed.  Different types of tube-to-tubesheet joints are explained and typical applications for shell-and-tube heat exchangers are listed.

Outlines common operating problems for air cooled heat exchangers (ACHE) such as: reduced air flow, dirty tube bundles, fan blade pitch, fouling, control and process conditions changes.  It also offers solutions to many of these common problems.

Discusses overall and film heat transfer coefficients and how they are calculated.  Offers typical values for overall heat transfer coefficients and film heat transfer coefficients.

Describes fouling mechanisms encountered in heat transfer equipment such as scaling and crystallization fouling, particulate and sedimentation fouling, corrosion fouling, chemical fouling, freeze fouling and biological fouling.  Pictures of each type of fouling are provided to help with identification.  Design tips to minimize fouling in heat exchangers are also provided.

Discusses the use of fouling factors in the design of heat exchangers and the physical and economic considerations which influence the selection of fouling factors.  A link to typical fouling factor values is provided.

Start-Up and Shutdown Procedures

Discusses the sequence for introducing at start-up and for removing at shutdown the hot and cold fluids in shell and tube heat exchangers to avoid damage from differential thermal expansion.