Soojusvaheti

Soojusvaheti is the Estonian term for a heat exchanger, a device that transfers thermal energy between two or more fluids at different temperatures while keeping the fluids physically separate. It is used in heating, cooling and energy systems to recover waste heat or to control process temperatures. Heat exchangers rely on conduction through a solid wall separating the fluids and on convection within each fluid, and they may use different flow configurations, with counterflow arrangements generally offering higher thermal efficiency than parallel flow.

Common types include shell-and-tube, plate, air-cooled and compact heat exchangers. Shell-and-tube exchangers consist of a bundle of tubes inside a shell, allowing one or more fluids to flow inside the tubes and the other fluid around them. Plate heat exchangers use corrugated metal plates to form a series of channels. Air-cooled exchangers transfer heat to ambient air, typically via fins and tubes. Compact and microchannel designs maximize surface area per volume for compact installations.

Performance is described by the heat transfer rate Q, the overall heat transfer coefficient U, the heat transfer area A, and the temperature driving force, often expressed as the log mean temperature difference ΔTlm. Design must consider pressure drop, fouling, material compatibility, corrosion, and thermal expansion. Common construction materials include stainless steel, copper and aluminum. Applications include heating and cooling in HVAC, power plants, chemical processing, refrigeration, oil and gas, and automotive radiators.

Standards and safety follow sector-specific codes and standards. Shell-and-tube exchangers are commonly categorized by the Tubular Exchanger Manufacturers Association (TEMA) standards; plate exchangers by manufacturer guidelines and applicable engineering standards; design codes from ASME or EN may apply to pressure-containing components.