Bilayer thermal harvesters for concentrating temperature distribution

Highly efficient thermal harvesting techniques are unfailing themes in the field of heat transfer. Owing to the unique and powerful manipulations on thermal field, great potentials on further promoting conventional harvesting techniques with tailored metamaterials have been presented. However, current harvesting schemes are mostly designed with independent wedge cells based on spatial transformations. Hence, the anisotropic parameters and difficult processes cannot be avoided, which restrict their potentials in practical applications. In this paper, such concern is addressed with the presentation of a class of bilayer harvesters for concentrating temperature distribution, which is designed by directly solving static heat transfer equations of adjacent regions without spatial transformations. Satisfied harvesting behaviors in tailored regions and non-distortional thermal profiles in ambient are numerically demonstrated. Furthermore, approximate harvesting efficiencies reveal that the previous meta-harvesters based on transformations can be efficiently replaced and innovated by the proposed schemes with homogeneous structures. The findings illustrate a novel and alternative function of designing efficient thermal harvesters for temperature distributions with homogeneous materials and simple structures, which present greater potentials on combining and motivating conventional harvesting techniques, such as solar thermal collector, and heat storage. (C) 2019 Elsevier Ltd. All rights reserved.