General arrangement of a shell-and-tube heat exchanger

2 General arrangement of a shell-and tube heat exchanger 

At each point in the heat exchanger, heat passes from the hotter fluid to the tube wall, and then from the tube wall to the cooler fluid. The tube wall will have its own dynamic response, and, just as it separates physically the two fluids, so it separates mathematically the calculations of the two fluid temperatures. Heat will also flow between the shell fluid and the shell wall, which will normally be heavily insulated to prevent heat flow to the environment. The shell wall will be relatively massive and cause a signiflcant slowing of the response of the shell-side fluid outlet temperature. 

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