Thermal Management of the Solar Evaporation Process.

Abstract

Solar-driven interfacial evaporation has caught wide attention for water purification due to its green and environment-friendly properties. The key issue is how to effectively utilize solar radiation for evaporation. To fully understand the thermal management of the solar evaporation process, a multiphysics model has been built by the finite element method to clarify the heat transfer process for the improvement of solar evaporation. Simulation results indicate that the evaporation performance can be improved by tuning the thermal loss, local heating, convective mass transfer, and evaporation area. The thermal radiation loss of the evaporation interface and thermal convection loss to the bottom water should be avoided, and local heating is good for evaporation. Convection above the interface can improve evaporation performance, although it would enhance the thermal convective loss. In addition, evaporation also can be improved by increasing the evaporation area from 2D to 3D structures. Experimental results confirm that the solar evaporation ratio can be improved from 0.795 kg m-2 h-1 to 1.122 kg m-2 h-1 at 1 sun with a 3D interface and thermal insulation between the interface and bottom water. These results can provide a design principle for the solar evaporation system based on thermal management.