The current unprecedented surge in population, combined with rising individual consumption of food, water, and natural resources, has begun to strain Earth’s capacity to sustain human life. The technology of solar steam generation which exclusively focusses on effective conversion of solar energy to thermal energy is highly anticipated to aid resolve this issue, specifically: the water issue. However, a novel concept that bypasses the application of the prevalent conventional technologies that employ complicated optical concentrators to enhance water evaporation, must be developed. At present, efficient solar steam generators have been seen to depend on efficient light-absorbers in the evaporators. Since metal-based absorbers are quite expensive, multilayer-composite absorbers have been developed. Nonetheless, these absorbers suffer from potential structural weakness and interfacial barriers to heat/mass transfer. Therefore, it is imperative that an inexpensive absorber of high energy conversion efficiency, possessing porous structures for efficient water desalination and of excellent mechanical robustness be developed.
Recently, Sun Yat-sen University researchers investigated the applicability of carbonized melamine foams obtained through one-step calcination as integrative solar absorbers to realize highly efficient solar steam generation. This was the first time such an application was being attempted. Their work is currently published in Journal of Material Chemistry A.
The research method employed commenced with preparation of integrative solar absorbers where the commercial melamine foams were heated in a tube furnace under nitrogen atmosphere. Next, the researchers characterized the porosity of materials > 99% with pore sizes in submicrometers as evidenced by the scanning electron microscopy. Additionally, cyclic compression tests indicated the mechanical robustness of the foams. Lastly, the system was tested for energy conversion efficiency.
The authors observed that the optimized integrative solar absorbers portrayed exceptional light absorption for solar energy due to the features of lightweight, high porosity, mechanical robustness innate from melamine foams, as well as low thermal conductivities attributed to the appropriate pore scale and high nitrogen content, beneficial for the decrease of thermal diffusions. In addition, they noted that the integrative solar absorbers could work out efficient water evaporation under a high humidity of 90%.
In summary, study by Sun Yat-sen University scientists presented a pioneering expedite where it was shown that carbonized melamine foams derived from commercial melamine foams via one-step calcination process could be used in high efficiency solar steam generation. Generally, it was seen that upon comparison with former reports, the optimized integrative solar absorbers reported herein exhibited one of the best performances for solar steam generation. Altogether, owing to their facile preparation, reusability, and aforementioned astonishing performance, the integrative solar absorbers can be anticipated to be possible solar absorbers for commercial, renewable and transportable solar steam generations.
Xiaofeng Lin, Jiayao Chen, Zhongke Yuan, Meijia Yang, Guojian Chen, Dingshan Yu, Mingqiu Zhang, Wei Hong and Xudong Chen. Integrative solar absorbers for highly efficient solar steam generation. Journal of Material Chemistry A, 2018, volume 6, page 4642.
Go To Journal of Material Chemistry A