Study On Solar-driven High-temperature Steam Generation At Ambient Pressure

Traditional high-temperature steam generation processes with the consumption of fossil fuels lead to severe environmental impact,such as the emission of greenhouse gases and water pollutions.With the concern of sustainability,it is necessary to utilize renewable energies to produce high-temperature steam.Recent studies have focused more on the increase of energy conversion efficiency by optimizing the designs and materials.Increasing the temperature of steam generated by the solar-driven technology is another important study for applications that involve in high-temperature steam.It is challenging to further raise the temperature of the steam at ambient pressure under lower solar fluxes.This paper demonstrates a facile solar steam generator for the generation of high-temperature steam at ambient pressure.The steam generator consists of a coiled copper tube(CCT)that serves as both solar collector and vapor heater.Both the inner and outer surfaces of the CCT are coated with black superhydrophobic copper oxide layer to improve the solar absorption,and such layer helps the generation and transportation of water vapor during the heating process.Solar vapor is generated at the inlet of CCT through interfacial evaporation and subsequently heated inside the CCT as the vapor travels from the inlet to the outlet.By employing this approach,steam temperature that exceeds 100 °C under1-sun illumination is demonstrated.Furthermore,steam temperature could reach as high as 250 °C under 10-sun illumination at ambient pressure.Successful sterilization experiment was also performed in this work to demonstrate the potential application of the high temperature steam generated.Such demonstrated approach helps open up the potential usage of solar-driven interfacial evaporation in applications that involve high-temperature steam,including medical sterilization,chemical manufacturing and food processing.