​The present study investigated modeling and optimization of a multi-tube heat exchanger (MTHE) network considering the effect of different on the tube side. After thermal modeling in ε-NTU method, optimization was performed from the perspective of increasing effectiveness and decreasing total annual cost as 2 objective functions, using 8 parameters, including number of MTHE and concentration. In addition, was performed at 3 various cold mass flow rates and different including AL₂O₃, and ZrO₂ (water). The results show that the Pareto front was improved in case, and the rate of improvement in CuO case, especially in higher effectiveness and lower mass flow rates is more significant compared with the other studied cases. In addition, because of the improved thermal performance of MTHE network in the case, the heat transfer surface area and consequently the volume of MTHE network for fixed values of effectiveness are significantly reduced. Finally, after display of the results of the design parameters versus effectiveness, sensitive analysis of particle concentration on the objective functions was performed for typical and the results were discussed.