Exchangers

Exchangers are engineering devices that enable the transfer of energy or matter between two streams at different conditions, without allowing the streams to mix. They are used to either heat or cool process streams, or to remove or add dissolved ions in solutions.

Heat exchangers transfer thermal energy between fluids separated by a solid barrier. Common configurations include shell-and-tube and plate heat exchangers. Performance is characterized by heat-transfer area, the overall heat-transfer coefficient, and driving temperature difference. Design must account for fouling, pressure drop, material compatibility, and operating costs.

Ion exchangers use resins to swap ions in solution with ions bound to the resin. Cation and anion exchangers are used for water softening, demineralization, and purification. Key metrics include exchange capacity, selectivity, and breakthrough. Resin beds require periodic regeneration with reagents to restore capacity and are disposed or regenerated.

Other exchangers exist, including gas–liquid contactors and regenerative exchangers in energy systems. Across types, material selection, corrosion resistance, and maintenance are important. Exchangers are integral to HVAC, power generation, chemical processing, and water treatment.