Design of Multipass Heat Exchangers: An Alternative Approach

Abstract

Multipass heat exchangers are often designed according to the rule of thumb FT ≤ 0.75. This criterion can give rise to poor designs. It is the slope (∂FT/∂P)R that is important, not just the absolute value of FT. Furthermore, in multishell arrangements, the number of shells required is usually evaluated by trial and error. This paper introduces an approach based on a new parameter that is an alternative to FT factors. The method is fully compatible with established design practice, takes account of the FT slope, and evaluates the number of shells explicitly in multishell cases.