Bioinspired design and optimization for thin film wearable and building cooling systems

Abstract

In this work, we report a paradigmatic shift in bioinspired microchannel heat exchanger design toward its integration into thin film wearable devices, thermally active surfaces in buildings, photovoltaic devices, and other thermoregulating devices whose typical cooling fluxes are below 1 kW m−2. The transparent thermoregulation device is fabricated by bonding a thin corrugated elastomeric film to the surface of a substrate to form a microchannel water-circuit with bioinspired unit cell geometry. Inspired by the dynamic scaling of flow systems in nature, we introduce empirically derived sizing rules and a novel numerical optimization method to maximize the thermoregulation performance of the microchannel network by enhancing the uniformity of flow distribution. The optimized network design results in a 25% to 37% increase in the heat flux compared to non-optimized designs. The study demonstrates the versatility of the presented design and architecture by fabricating and testing a scaled-up numerically optimized heat exchanger device for building-scale and wearable applications.

Biological and Bioinspired Thermal Energy Regulation and Utilization

“…Aizenberg et al further empirically derived the sizing rules and developed a numerical optimization method to enhance the mass flow and temperature distribution uniformity (Figure 13c). 116 With the optimized design, the heat dissipation flux can be increased by 37%, if compared to the nonoptimized one. This optimized microchannel heat exchanger could be integrated into wearable devices, buildings, and photovoltaic devices for temperature regulation.…”

“…This optimized microchannel heat exchanger could be integrated into wearable devices, buildings, and photovoltaic devices for temperature regulation. 116 The hierarchical vascular structure in leaf veins and in plant stems (Figure 13d) also inspired the fabrication of advanced cooling textiles. Ding et al fabricated a cooling textile woven with aligned PU/boron nitride nanosheet (BNNS) fibers (Figure 13e, left).…”

“…By circulating room-temperature water inside the vascular network (Figure b), the temperature of the window could be reduced by 7–9 °C. Aizenberg et al further empirically derived the sizing rules and developed a numerical optimization method to enhance the mass flow and temperature distribution uniformity (Figure c) . With the optimized design, the heat dissipation flux can be increased by 37%, if compared to the nonoptimized one.…”

“…With the optimized design, the heat dissipation flux can be increased by 37%, if compared to the nonoptimized one. This optimized microchannel heat exchanger could be integrated into wearable devices, buildings, and photovoltaic devices for temperature regulation …”

“…(c) IR images showing the temperature distribution of vascular structure before (i) and after (ii) optimized design. Reproduced with permission from ref . Copyright 2021 IOP Publishing.…”