Coiled Tubular Heat Exchangers

Abstract

The development of the coiled tubular heat exchangers (CTHE) is closely related to the development of cryogenic technology. The first commerical liquefaction of air, made in 1895 by von Linde [¹] in Germany and shortly thereafter by Hampson [²] in England, was achieved by the use of two types of coiled tubular exchangers. The first Linde exchanger consisted essentially of a long, helically wound concentric tube. Figure 1 shows a reproduction of the first Linde design of 1896 for an apparatus for the continuous production of “oxygen-rich air.” In this design, compressed air was divided into two streams and cooled in separate countercurrent coiled tubular heat exchangers with a low-pressure oxygen-rich stream O⁺ and a low-pressure nitrogen-rich stream N⁺, obtained by partial condensation of air. Various improvements to this heat exchanger type have since been built. Obviously, this design gives true counterflow, but relatively poor overall heat transfer coefficients due to channel flow on the low-pressure side.