Pathways to Energy‐efficient Water Production from the Atmosphere

Abstract

Atmospheric water harvesting (AWH) provides a fascinating chance to facilitate a sustainable water supply, which obtains considerable attention recently. However, ignoring the energy efficiency of AWH leads to high energy consumption in current prototypes (ca. 10 1 to 10 2 MJ kg −1 ), misfitting with the high-strung and complicated water-energy nexus. In this perspective, a robust evaluation of existing AWHs is conducted and a detailed way to high-efficiency AWH is paved. The results suggest that using cooling-assisted adsorption will weaken the bounds of climate to sorbent selections and have the potential to improve efficiency by more than 50%. For device design, the authors deeply elucidate how to perfect heat/mass transfer to narrow the gap between lab and practices. Reducing heat loss, recovering heat and structured sorbent are the main paths to improve efficiency on the device scale, which is more significant for a large-scale AWH. Besides efficiency, the techno-economic evaluation reveals that developing a cost-effective AWH is also crucial for sustainability, which can be contributed by green synthesis routes and biomass-based sorbents. These analyses provide a uniform platform to guide the next-generation AWH to mitigate the global water crisis.

Sorption‐Based Atmospheric Water Harvesting: Materials, Components, Systems, and Applications

“…The results indicate that the use of cooling-assisted adsorption can weaken the limits of climate in sorbent selections, and recent studies estimate a 50% enhancement in the efficiency of SAWH. [128] To summarize the material and design sections, the novel synthetic sorbents (e.g., MOFs and hydrogels) have surpassed the traditional sorbents. However, hygroscopic hydrogels usually limit the amount of water generated per unit time because of slow sorption kinetics.…”

“…Despite the material level tests, which place a small amount of adsorbent in an ideal condition with the highest mass and heat transfer coefficient, in a system level, the design of the bed and condenser plays an important role in achieving this ideal condition. To narrow the gap between lab-scale and real-size AWHs, Feng et al [130] explored how to improve heat and mass transfer. They concluded that reducing heat loss, recovering heat, and structured sorbent are the main paths to improve efficiency on the device scale, especially in a large-scale SAWH.…”

Redesigning Natural Materials for Energy, Water, Environment, and Devices

“…64 Although the abundance and low cost of cellulose materials move atmospheric water harvesting one step closer to market, the overall thermodynamic efficiency and system design are still the major bottlenecks to commercialization and competitive market share. 65 PART 3: WEARABLE DEVICES Some properties and phenomena mentioned in the preceding sections also relate to device design and implementation as another important branch. With the development of materials, fabrication processes, and system design, functionalizing naturally fibrillated materials facilitates applications in optics, 68 acoustics, 69 electronics, 70 and optoelectronics.…”

Sustainable Hierarchical-Pored PAAS–PNIPAAm Hydrogel with Core–Shell Structure Tailored for Highly Efficient Atmospheric Water Harvesting

“…2−4 Related studies showed that atmospheric water is very rich, accounting for about 10% of the lake water in the world. 5 Therefore, atmospheric water harvesting technology has attracted the interest of researchers and become one of the effective ways to capture freshwater.…”

“…If continues, it is estimated that the number of people over the world with water shortage is expected to reach 5 billion by 2050, which will have a severe impact on global water security . In response to this serious problem, people have adopted some effective methods to develop freshwater resources on the earth, such as seawater desalination, sewage treatment, atmospheric water harvesting, etc. − Related studies showed that atmospheric water is very rich, accounting for about 10% of the lake water in the world . Therefore, atmospheric water harvesting technology has attracted the interest of researchers and become one of the effective ways to capture freshwater.…”