An Integrated Algorithm for The Thermal Design of a Heat Exchanger

ABSTRACT: The thermal design of a shell and tube heat exchanger is executed basically by the procedure developed by Kern. However, physical properties, tube sizes and estimation of the other design parameters like heat transformer coefficients, pressure drops on tube side and shell side etc., require reference to tables and plots. With the advent of computers and their very fast development, very powerful and low cost computers with huge memory are available in the market. Hence, all the tables and data from plots can be stored in the computer (or the data can be correlated by using linear or non-linear equations by the method of least squares ‘fit) and for varied industrially important systems, the thermal design can be executed with considerable ease. It should be noted that if it is necessary to execute the thermal design for a number of exchangers for a chemical plant with varying flow rates and temperatures, it could be done by using matrices to develop the computer program and also store the short-cut equations related with physical properties, tables, graphs etc. the heat exchanger can be accurately designed if the exchanger is divided into numerous sections. This is done so as to get precise values of all the output design variables affecting the cost of the exchanger. It is concluded that the concept of designing heat exchangers by dividing into sessions has been found to be compatible with the results obtained by conventional methods. Further, extensive information in the form of output variables are obtained and simple shortcut equations obtained are quite accurate (fro plant practice) and compact. More importantly, if the systems used in the different exchanger are similar, then in one stroke the short-cut equations give adequate results sufficient for the design of a number of exchangers without actually going through the sequence of conventional thermal design. It should be noted that the principle of dividing equipment into thermal sections can be used extensively for varied unit operations best process equipment