Effect of porous properties on self-cooling of fired clay plate by evaporation of absorbed water

Porous ceramic plates were prepared from clay and wood charcoal powder at 900 and 1100 °C and their porous properties, water absorption and the cooling effect of porous plates were investigated to produce eco-friendly porous ceramics for cooling by the evaporation of absorbed water. Porous properties were dependent on the firing temperature, and total pore volume, average pore size and porosity, which were 0.38–0.39 cm³/g, 0.15–0.17 μm and 49–50%, respectively at 900 °C and 0.31–0.33 cm³/g, 2.47–2.59 μm and 43–44%, respectively at 1100 °C. By the addition of wood charcoal powder, the cooling rate of porous plate fired at 1100 °C was 1.7 times faster than that of the plate fired at 900 °C and the cooling temperature difference (∆T) was around 2.3 °C at 22.5 °C and 52–54% of relative humidity and around 3.2 °C at 29 °C and 77–80% of relative humidity. The porous ceramic plates developed here are potential materials for cooling buildings.