Optimizing structures to heat and mass processes is a hot research topic. Compared with conventional structural optimization method, the topology optimization method with highest freedom can design structures that go beyond human intuition. During the past ten years, we have developed topology optimization method for convective heat and mass transfer processes based on the adjoint method. The topology optimization method is then adopted to enhance heat and/or mass transfer processes related to chip cooling, PEM fuel cell, energy storage, etc. Structures with lower flow and heat resistance are designed and validated.