Balance of heat management and salt-resistance on solar interfacial evaporator actively adjusted by the electric field with periodically changed direction

Abstract

Interfacial desalination is one of the most promising technologies in solar energy utilization, but it usually needs to balance the heat management and the salt-resistance. Dealing with this, the electric field with periodically changed direction for various reversing times could be used to regulate the interfacial desalination. Hence, the evaporator performances including the evaporation rate, evaporation efficiency, salinity of vapor and surface salt-deposition morphology are investigated in this paper. The experimental results show that the periodical electric field has regulative mechanisms of phase change heat transfer, ion diffusion, and salt crystallization on interfacial desalination. By changing the polarity of the high potential electrode, the salt crystals are rarely observable on the evaporator surface even in the 20 wt% NaCl solution, and the evaporation performance of evaporator would be distinct with different reversing time. Besides, the performance of evaporator could be maximized by the electric field with the reversing time of 20 s, which could increase the evaporation rate up to 36.5 % and the evaporation efficiency from 61.9 % to 90.7 %. The combination of the periodical electric field and the interfacial desalination technology with extremely low consumption could be deemed as a solution for the efficient solar utilization.