Heat exchangers transfer thermal energy between fluids without direct contact, enabling process heating and cooling, energy recovery, and temperature control across industries. These essential devices range from simple shell-and-tube configurations to complex plate-and-frame designs optimized for specific applications.

Common heat exchanger types include shell-and-tube (versatile, proven), plate-and-frame (compact, high efficiency), air-cooled (no water required), and specialized designs like spiral, brazed aluminum, and double-pipe exchangers. Selection depends on fluids, temperatures, pressures, fouling tendencies, space constraints, and costs.

Fabricating heat exchangers requires tube-to-tubesheet welding or rolling, shell fabrication to ASME code, channel and head construction, baffle fabrication and installation, and hydrostatic testing to verify integrity. Material combinations address corrosion on both shell and tube sides while accommodating differential thermal expansion.

Heat exchanger performance depends on design—surface area, flow arrangement, turbulence promotion—and fabrication quality—tube joint integrity, baffle spacing accuracy, gasket sealing surfaces. Poor fabrication causes leakage, vibration, or performance degradation.