An expert system for heat exchanger selection/design has been developed. The first of three parts is a database that contains information about the different types of heat exchangers. The second part helps the user select a suitable heat exchanger, and the last part helps the user design a shell-and-tube heat exchanger. The important aspect of the expert system is that the database and the if-then rules are dynamic, which means that they can be deleted or added in the course of running the expert system. This provides the user-modifiable aspect of the expert system. The variables, the relational operators, and the logic operators in the if-then rules are stored in a rule file as integers. The system can read/write/translate/execute the if-then rules, which comprise five conditions.

KEYWORDS: heat exchangers, expert systems, selecting, designing, databases, shell and tube heat exchangers.