Nanoparticle-based solar vapor generation: An experimental and numerical study

Steam generation by nanofluid under solar radiation has attracted intensive attention recently. Due to strong absorption of solar energy, nanoparticle-based solar vapor generation could have wide applications in many areas including desalination, sterilization and power generation. Steam generation of different concentrations of gold nanoparticle dispersions under focused sunlight of 5 sun and 10 sun were performed in this work. A numerical model combining radiative heat transfer, moisture transport, and laminar flow was established to investigate the temperature profile, evaporation rate above the surface and radiative intensity distribution inside the nanofluid. It was found that localized energy trapping at the surface of nanofluid was responsible for the fast vapor generation. To convert more solar radiative energy into latent heat of water (i.e., to vaporize water) at the surface, a new method was proposed to optimize the range of nanofluid concentration and optical depth for future solar vapor generator design