A Calculation of Nodal Temperatures

In this appendix, calculation of nodal temperatures in HEN is described using an example. Consider a HEN with two hot streams and one cold stream, whose data are in Table 7.A.1. Assume the number of nodes is 4 on each of the three streams, and nodal temperatures supplied by the user for all streams are given by the following vector [Equation (7.A.1)]  

In the above, the first, second and third rows correspond to streams HI, H2 and Cl, respectively. The HEN stmcture generated by the optimizer can take a maximum value of 4 for nodes, but the temperature of the stream leaving the 4th node needs to be calculated. This is the reason for having 5 nodal temperamres for all streams in when the maximum number of nodes is only 4. Initial nodal temperatures can be any values within the stream supply and target temperatures, and they need not include target/supply temperatures (as seen in the third row of t ). 

Assume the HEN structure generated by optimizer = ( ) here, the first row 

After heat exchanger 1 calculations, is given by Equation (7.A.2)  

Similarly, calculations for outlet temperatures of heat exchanger 2 are  

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