parallel-flow heat exchanger

A parallel-flow heat exchanger is a device that transfers heat between two fluids flowing in the same direction. It's a type of heat exchanger, which is any device that moves heat from a hot fluid to a cold fluid.12

In a parallel-flow setup, one fluid typically flows through an inner tube while the other flows in the space surrounding it. Heat is transferred across the inner tube's wall, which acts as the heating surface. This method is used in various applications, including cooling petroleum fractions, preheating combustion air for boilers, and in nuclear power plants to cool metals. While effective, other flow arrangements like counterflow, where fluids move in opposite directions, and cross-flow, where one fluid moves perpendicular to the other, also exist.1