The innovation team ITEWA (Innovation Team for Energy, Water & Air) led by Prof. Wang Ruzhu from School of Mechanical Engineering at Shanghai Jiao Tong University, published a research paper titled "Passive and continuous moisture pump for humidity regulation via simultaneous water adsorption and desorption" in the Cell sister journal the Device. To address the demand for dehumidification in various scenarios, this paper proposes a passive continuous humidity pump via simultaneous adsorption and desorption. Incorporating a salt-impregnated composite sorbent, the moisture pump features a three-dimensional "wristwatch" structure that spatially separates the adsorption and desorption processes to enable the simultaneous adsorption and desorption process, thus realizing continuous dehumidification. Breaking through the limitations of traditional continuous dehumidification technologies that rely on active energy input, this paper provides a valuable proposition for the design of future humidity control technologies. Yu Jiaqi, a Ph.D. student from School of Mechanical Engineering at Shanghai Jiao Tong University, is the first author of the paper, with Professor Wang Ruzhu as the corresponding authors.

Humidity control is an important function for high-humidity environments, including residential, offices, factories, and also greenhouses. However, most dehumidifing technologies consume significant amounts of electricity or require complicated mechanical components to achieve continuous operation. These components are often difficult to manufacture and often expensive. Therefore, researches on low-cost, high-efficiency passive continuous dehumidification technology are important for the sustainable development of the future building humidity control.

To achieve continuous and passive dehumidification, a sorption-based moisture pump is propose, which is installed between the wall of buildings. Under solar radiation, the outdoor-side sorbent of this moisture pump increases its temperature, thus triggering its desorption to release water vapor. The indoor-side sorbent maintains around room temperature, conducting the corresponding water adsorption process. To achieve this process, a salt-impregnated composite sorbent (LiCl@ACF) is designed in the shape of a wristwatch. This structure contributes to establishing a high-temperature gradient of the sorbent between the indoor side and the outdoor side, further allowing simultaneous adsorption and desorption processes to occur. In a stable high-humidity setting, the average dehumidification rate of the moisture pump attains 256.20 g m-2 h-1, which is much higher than that of the two-dimensional LiCl@ACF. Begin with an initial state of saturated water uptake, the indoor humidity could be decreased from 70% to 50.8% by this sorbent-based moisture pump. Furthermore, in the greenhouse model with the outdoor experiment, 3D-LiCl@ACF demonstrated a capacity to maintain proper humidity level, after the humidity of the prototype with bulk desiccant had exceeded RH80% for 5.5 hours.This paper also compares the moisture pump with other active and passive dehumidification technologies in terms of energy consumption and cost. It demonstrates that the proposed moisture pump outperforms the data reported recently, indicating its potential for scaling up and promotion.

Prof. Wang Ruzhu's innovation team in the field of energy-water-air has long been committed to addressing fundamental scientific problems and key technologies at the forefront of the interdisciplinary intersection of energy, water, and air. Their aim is to achieve comprehensive solutions at the material-device-system level through interdisciplinary approaches, driving breakthroughs in related fields. In recent years, the team has published a series of interdisciplinary papers in high-level journals such as Science, Nature Communications, Joule, EES, Advanced Materials, and more.

Paper Links: https://doi.org/10.1016/j.device.2024.100429