A new device of 3D hollow-cone structure that can greatly increase the solar-thermal conversion efficiency has been developed by a team of Chinese scientists. Named as ‘Artificial Transpiration’, the device is inspired by the transpiration process of trees.
A report, published in April 2018 in the National Science Review, an English journal affiliated with the Chinese Academy of Sciences, informs that the cone structure is based on a graphene film. It can collect more sunlight throughout the day when compared with a flat device, as about 10 per cent to 50 per cent of sunlight is diffusive. Moreover, it has a special 1D water path within it, which can reduce the energy loss in conduction. As a result, the device can enhance the solar-thermal conversion rate to 85 per cent, much higher than the common devices that enhance conversion rate to only 40 per cent.
Scientists applied this device to solar waste-water treatment and the test showed that the device could not only recover clean water but also recycle heavy metals such as copper and cadmium. The device can be further optimised to have a longer life-time and recycle more heavy metal.
The device will open up new possibilities in utilisation of solar energy, as many sectors have refrained from using solar power because of its low conversion rate caused by losses in radiation, convection and conduction.