Design optimization for evaporation property of coal fly ash-based evaporator during solar-driven interfacial evaporation process.

Solar-driven interfacial evaporation has recently attracted many attentions due to its energy-saving and environmentally friendly advantages. Researches on structural parameters optimization for the ceramic interfacial evaporators to improve their evaporation performance are lack. In this work, ceramic evaporators with different structural parameters are prepared using coal fly ash as the main material. A comparative experimental study was carried out under natural light. Water transport rate and maximum water transport volume of evaporators are introduced to explain the effect of structural parameters on the evaporation performance. Results indicate that smaller pore size and higher porosity can enhance the water transport and improve the evaporation rate. Evaporators with higher porosity has higher maximum water transport volume, thus the evaporation rate can be reduced due to the increase of the thermal conductivity of the evaporator. The optimized evaporator shows a high average evaporation rate of 4.72 kg·m·h under a solar irradiation of 0.66 kW·m, and an average evaporation rate of 5.85 kg·m·h under one sun irradiation, with the mean pore size of 0.2204 μm and the porosity of 0.2855. This work provides a direction for structural parameters optimization in designing high-performance ceramic evaporators.