Using nanoparticle in the fluid is a novel engineering issue which could improve the performance of heat exchanger. The main goal of this study is determining the effect of different nanoparticle shapes on the thermoeconomic improvement of a shell and tube heat exchanger (STHE). For this purpose, Boehmite alumina is selected as a nanoparticle with the four different shapes including platelets, blades, cylindrical and bricks. Then the heat exchanger annual cost and effectiveness are optimized by considering the mentioned nanoparticle shapes additive and the results are compared with each other and with the absence of nanoparticle additive. Nine design parameters such as particle volumetric concentration and flow allocation are selected and optimization is performed for the different sets of hot and cold side mass flow rates. The optimum results reveal that heat exchanger thermoeconomic parameters are improved higher in the case of bricks as nanoparticle shape and generally followed by blades, cylindrical and platelets shapes. For example, 1.24% grown in the effectiveness and 3.75% reduction in the annual cost are observed in the case of blades shape nanoparticle compared with the case of without nanoparticle. In addition it is observed that, higher particle concentration is needed in the case of blades and bricks nanoparticle shapes as compared with the other studied shapes. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.