Porous Nickel as a Selective Emitter for Surface Cooling in Various Environments

As large-scale manufacture of artificially engineered structures becomes more viable, the ability to create surfaces with a specific morphology and controlled radiative properties are becoming a possibility. By modifying geometric quantities, spacing, and topography of surface structures, the surface emissivity can be selectively tuned for specific wavelength bands; the objective for cooling applications is to maximize energy emitted from the surface while minimizing energy absorbed. Specifically, the design intent is to dramatically reduce the effect of solar irradiance on a surface-while simultaneously emitting energy from the surface within the atmospheric transmission window (mid-IR) for atmospheric applications, and emitting in similar low-input bands. Using Rigorous-Coupled Wave Analysis (RCWA) and computational modelling we explore optimal designs for passive system-level cooling in various environmental conditions including studies of humidity and air flow dependencies. Furthermore, we will show that significant system level cooling can potentially be achieved by porous nickel structures that does not require power or active cooling components.