Enhanced thermoelectric system by dual-band radiative cooling for all-day energy harvesting

Amidst the escalating global energy requirements and environmental concerns, the pursuit of efficient, sustainable energy solutions has emerged as a critical global priority. Combining radiative cooling (RC) with thermoelectric technology presents new possibilities for all-day, zero-energy temperature differential power generation. Here, we propose a system that combines a dual-band radiative cooling (DRC) structure with thermoelectric technology, achieving continuous and stable power generation through optimized RC performance. The DRC structure exhibits excellent broadband radiation characteristics in both the 8–13 μm and 16–25 μm bands, with average emissivities of 83.2 % and 67.5 %, respectively. Furthermore, the system maintains good cooling performance under various incidence angles and heat transfer coefficients. Upon integrating the cold side of the thermoelectric generator with the DRC component, the system demonstrates outstanding performance in dry, high-temperature environments, achieving a maximum temperature difference of 6.6 K and a power density of 0.28 W m−2. Compared to traditional single-band selective emitters and broadband RC technologies, the design combining the DRC structure with thermoelectric technology exhibits superior performance in temperature difference and output power. Thus, the system offers an efficient, economical, and eco-friendly way to maintain cooling and ensure uninterrupted power, achieving energy conservation.