Efficient radiative cooling with bi-rhombic metamaterial and its application in thermoelectric power generation

In this work, we have not only demonstrated a bi-rhombic radiative cooling metamaterial but also explored its application in power generation. It exhibits ultrahigh broadband emission in both the first and second atmospheric windows. The net cooling power reaches up to a value of 165.09 W/m2 in the daytime. Based on the analysis of the electric field distribution, such high emissivity in the atmospheric window derives from the patterned metamaterial and the inclusion of the dielectric layer. Moreover, excellent cooling performance is maintained at different incident angles and heat transfer coefficients. The cold end of the thermoelectric generator is coupled to the radiative cooler, which allows for a maximum temperature difference of 8.28 K during the daytime, resulting in continuous and stable power generation. Therefore, the design of bi-rhombic radiative cooling metamaterial provides a simple, economical, and environmentally friendly method to achieve efficient cooling and continuous power generation, thereby enhancing the efficiency of energy utilization.