Solar heat harvesting and transparent insulation in textile architecture inspired by polar bear fur

Solar thermal technology is a promising key strategy for future renewable energy production. Various concepts exist that use solar collectors and heat mirrors, built from rigid materials, to gather thermal energy from solar radiation. A new approach is the utilization of textile materials to build solar thermal collector systems with flexible material properties, lightweight design and improved material-efficiency. A solar collector, based on a multi-layer arrangement of technical textiles and foil membranes, has been realized by the ITV Denkendorf (Institute of Textile Technology and Process Engineering Denkendorf). The proposed collector system allows transparent insulation in textile-based buildings while gathering thermal energy simultaneously. The system is inspired by the transparent insulation and heat harvesting strategies of polar bear fur and can inform textile-based envelopes of future transparent buildings. In this study, different material arrangements and the influence of different parameters on the temperature distribution along the collector were tested. Air temperatures up to 150 °C (302 °F) could be generated inside the collector system. Furthermore, a closer look at the polar bear fur and other related principles in nature delivered additional concepts for energetic optimization.