Experimental study of electric field combined nanofluid to enhance vapor generation in the solar steam generator

Volumetric solar steam generation has a wide range of applications in many fields such as electricity generation, water purification, seawater desalination, and wastewater treatment. However, the efficiency of volumetric evaporation using nanofluids as photothermal conversion materials is still low. In this paper, electric field is applied to the volumetric solar steam generation system to enhance steam generation efficiency by utilizing the effect of electric field on nanoparticle resuspension as well as the formation and escape of nanobubbles. The results show that the electric field promotes steam generation at high solar radiation intensities and the promotion is enhanced with the increase of voltage. The steam generation of 0.09 vol% TiN-water nanofluid at 10 kV and solar radiation intensity of 3 sun significantly increases by 21.71 % than that without electric field. Electric field provides an external force for the movement of nanobubble-particle complexes, accelerating the process of rise, fusion, and escape of nanobubbles, and accelerating the resuspension as well as upward and downward circulation of nanoparticles in the cavity. Thus, the vapor generation efficiency is enhanced. The research in this paper provides theoretical guidance to enhance vapor generation in the solar steam generator.