Solar-driven high-temperature steam generation at ambient pressure

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 superhydrophobic layer prevents the condensation and clogging 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 under 1-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.