Optimization-based design of easy-to-make devices for heat flux manipulation

In this work, we present a new method for the design of heat flux manipulating devices, with emphasis on their manufacturability. The design is obtained as solution of a nonlinear optimization problem where the objective function represents the given heat flux manipulation task, and the design variables define the material distribution in the device. In order to facilitate the fabrication of the device, the material at a given point is chosen between two materials with highly different conductivity. By this way, the whole device can be seen, in the large scale, as a metamaterial having a specific anisotropic effective conductivity. As an application example, we designed the heat flux inverter shown in Figure a, which was so simple that it could be hand-made as shown by Figure b. The performance of this device for heat flux inversion was experimentally tested and validated (see Figure c), proving that it was more efficient than a more complex device designed using the classical transformation thermodynamics approach.221