In this study

an optimization method based on genetic algorithm and entransy dissipation theory is applied to the optimization design of the plate fin and tube heat exchangers in fan coil units. Two examples

i.e. the heat exchanger in a cooling dry fan coil unit and the heat exchanger in a heating fan coil unit

are studied and reported. Both of the two heat exchangers have plate fin and tube structure

but with different conditions and constraints. The optimization objective selected is the entransy dissipation based thermal resistance

and the design variables are the transverse tube pitch

longitudinal tube pitch

tube outside diameter

fin pitch and number of fins. To evaluate the performances of the heat exchanger

the heat transfer rate

air side and water side pressure drop

total pumping power and effectiveness are used as the evaluation index. The optimization results show that both the entransy dissipation based thermal resistance and other performances are improved

under the specific conditions in the current study.