Method of designing heat exchanger group and processing plant

A method of designing a heat exchanger group, which is installed in a processing plant configured to process fluid to be processed and includes a plurality of air cooled heat exchangers (ACHEs), the method comprising:

• a first step of setting at least one design variable selected from a design variable group consisting of a design variable relating to a tube bundle to be provided to each of the ACHEs, a design variable relating to each of heat transfer tubes to be included in the tube bundle, and a design variable relating to a fan to be provided to each of the ACHEs, and the number of installed ACHEs in the heat exchanger group as variable parameters and setting a variable range of each of the variable parameters;
• a second step of setting a design value of each of the ACHEs, which is included in the design variable group and includes a value of the design variable non-selected as the variable parameter;
• and
• a third step of, after the setting of the design value, calculating Pareto solutions for at least two objective functions selected from an objective function group consisting of an installation length of the heat exchanger group when the plurality of ACHEs are arranged in one row, a total heat transfer area of the heat transfer tubes to be included in the heat exchanger group, and total power consumption of the fans included in the heat exchanger group with use of a computer while changing the variable parameters.