Effects of pigment volume concentration on radiative cooling properties of acrylic-based paints with calcium carbonate and hollow silicon dioxide microparticles

Radiative cooling paints offer a sustainable method for reducing energy demand in buildings. This work investigates the effects of particle volume concentration (PVC) of calcium carbonate (CaCO3) and hollow silicon dioxide (SiO2) microparticles in acrylic-based paints on cooling capability. Paint solar reflectance increases as the total PVC increases until a peak PVC is reached. The addition of CaCO3 improves solar reflectance due to an enhancement in near-infrared reflection but decreases thermal emission. The paint, with a total PVC of 0.45 and a CaCO3:SiO2 PVC ratio of 1:1, offers the right balance between solar reflection and thermal emissivity and achieves the best cooling performance. This work demonstrates that the CaCO3-SiO2 paint system allows tuning of the radiative cooling performance.