Leidenfrost limit enhancement via supersonically sprayed iron carboxylate framework for convection cooling

Abstract

Device cooling schemes are required to reduce the local temperature of solar panels and solar air heaters, while maintaining their radiative heat to maximize energy conversion. Therefore, an efficient cooling scheme was developed using textured surfaces augmented by highly porous materials for increasing their total surface area. In this study, highly porous iron carboxylate framework, MIL-100(Fe), Materials of Institute Lavoisier, was introduced to substrates to provide a highly textured surface. This significantly reduced the temperature of the surface that was subject to radiative heat during both air and mist (or aerosol) cooling. In the case of mist cooling, the proposed MIL-100(Fe)-coated substrates were superhydrophilic, which promoted close contact between the impacting aerosols and the heated surface. Single drop impact and evaporation experiments were conducted to quantify the rate of heat removal provided by the proposed MIL-100(Fe) coatings. These coatings provided an increase in the Leidenfrost limit from 140 to 200 °C. As such, the highly wettable and porous MIL-100(Fe)-coated layers promoted rapid evaporative cooling. The proposed layers were analyzed using scanning electron microscopy, x-ray diffraction, atomic force microscopy, and Brunauer–Emmett–Teller data to elucidate the reason for their increased heat transfer rate.