Water wave vibration-promoted solar evaporation with super high productivity

Abstract

Interfacial solar evaporation holds great potential for water desalination; other sustainable energy resources naturally coexisting with solar energy (e.g., wind and water wave), however, have rarely been exploited to augment solar evaporation, especially in closed conditions. Herein, we developed a novel system that had an interfacial solar evaporator integrated with an angularly vibrating cantilever beam, harnessing both solar and water wave energies when floating on water surfaces for efficient water desalination. Super high evaporation rates of ~ 3.1 and 1.9 kg m−2 h−1 under simulated sunlight and vibrations were obtained in open and closed conditions, respectively. In outdoor tests floating on lake water surfaces, the cantilever beam effectively responded to realistic water waves of varying low frequencies and amplitudes, and the system delivered a high condensate collection rate of ~ 1.8 kg m−2 h−1. Mechanism studies revealed that the vibrating cantilever beam promoted vapor flow and condensation on selective surfaces. The cantilever beam enabled the direct mechanical energy transfer from water waves to moisture flow without using any electronics, resulting in great system-operation-maintenance simplicity. This work provides new insights on advancing solar desalination with the simultaneous and rational utilization of multiple sustainable energy resources.