A magnetic-enhanced 3D solar-absorbed structure inspired by cold evaporated heatsink for vapor generation

Solar energy is promising for application in vapor generation and desalination that is reliant on conventional high-temperature fluid methods due to its renewable energy properties. Existing desalination technology has encountered a bottleneck due to high energy consumption, low water purity and high costs. In this work, a novel magnetic three-dimensional solar vapor generator inspired by cold evaporated heatsink is designed based on carbon fiber felt, which has the ability to efficiently absorb solar energy and evaporate seawater. In addition, a seawater desalination coupling salt production device is built, utilizing the photo-thermal interface as a means of accelerating both the evaporation and salt extraction processes using a magnetic field. Experiments and simulations are conducted to analyze the effects of materials, surface properties, device structure, solar illumination intensities and magnetic field conditions on evaporation efficiency. The results show that the device is able to achieve cold evaporation and harvests energy from the environment, reaching an evaporation efficiency of 130.7% under 1 sun illumination. Furthermore, with a magnetic field power of 5 kW m−2, the device is able to achieve a remarkable evaporation rate of 7.05 kg m-2h−1 under 1 sun illumination, which enables rapid fresh water extraction in extreme conditions. The device is simple in structure, cost-effective, and can be widely used in areas that face water and salt shortages.