Convection Cooling Enhancement for Energy Conversion Systems Using Rhombic-Dodecahedral-Zeolitic-Imidazolate-Framework-8-Nanotextured Surfaces

Abstract

Evaporative cooling is an efficient approach for removing heat from nuclear reactors, solar power plants, solar panels, and energy storage devices, such as lithium-ion batteries and fuel cells. Nanotextured surfaces can provide improved evaporative cooling by increasing the total surface area to enhance the heat transfer rate and reducing the temperatures of local hotspots. In this study, we introduced rhombic dodecahedral zeolitic imidazolate framework-8 (ZIF8), a class of metal-organic frameworks, via impregnation to create nanotextured surfaces. The impregnation time was varied to obtain various thicknesses of ZIF8. We found that the increased surface area of ZIF8 improved convection cooling, which considerably reduced the temperature of the heated substrate. Air, mist (buoyant aerosols), and spray (inertial droplets) were independently used as coolants to compare the cooling performance of noncoated (bare) and ZIF8-coated substrates. Compared to the noncoated substrate, the optimal ZIF8 film yielded temperature reductions of $\Delta T=13$ °C and 10°C for air and spray cooling, respectively.