Mean Temperature Difference for Shell-and Tube Heat Exchangers with Condensing on the Shell Side

Abstract

Shetl-and-tube heat exchangers with condensing on the shell side usually have a nonlinear heat release curve and a variable shell-side heat transfer coefficient. Using an effective average coolant temperature, it is possible to separate the calculation of the mean temperature difference from the heat transfer coefficient. Thus, it is possible to calculate the weighted mean temperature difference before the heat transfer coefficients are calculated. As a result, the complexity of the calculations is greatly reduced from present incremental procedures. When compared to a detailed incremental calculation of the mean temperature difference, tht maximum error is about 2%. A manual incremental method is also presented, which requires only moderately more work than industrial methods that use average heat transfer coefficients.