A Thin Walled Double Pipe Counterflow Heat Exchanger. Heat exchangers are typically classified according to flow arrangement and type of construction. The simplest heat exchanger is one for which the hot a schematic of a counterflow heat exchanger is shown in figure 18.11.
The double pipe heat exchanger works via conduction, where the heat from one flow is transferred through the inner pipe wall, which is made of a conductive material such as steel or aluminum.
The high stresses produced by differential thermal expansion between outer and inner pipes flow pattern is strictly counterflow; The double pipe heat exchanger is one heat exchanger pipe inside another larger pipe for either counter flow or parallel flow pattern. Consider we have a double pipe heat exchanger, with the inner tube of diameter 20mm (neglect thickness) and outer tube of diameter 30mm. This heat exchanger consists of two concentric pipes of different diameters.