Good Thinking

Self-contained SmartFarm grows plants using water drawn from the air

Self-contained SmartFarm grows...
The current prototype is a miniature proof-of-concept model – full-size systems could be used in locations such as rooftops within cities
The current prototype is a miniature proof-of-concept model – full-size systems could be used in locations such as rooftops within cities
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The current prototype is a miniature proof-of-concept model – full-size systems could be used in locations such as rooftops within cities
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The current prototype is a miniature proof-of-concept model – full-size systems could be used in locations such as rooftops within cities
The research team, from left to right: Asst. Prof. Tan Swee Ching, Mr. Qu Hao, Ms. Yang Jiachen and Dr. Zhang Xueping
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The research team, from left to right: Asst. Prof. Tan Swee Ching, Mr. Qu Hao, Ms. Yang Jiachen and Dr. Zhang Xueping
A diagram of the SmartFarm system
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A diagram of the SmartFarm system
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In many parts of the world there may not be much precipitation, but there is a fair amount of water vapor in the air – particularly at night. An experimental new device draws in that vapor, then uses it to irrigate edible plants.

Known as the SmartFarm, the small-scale prototype was designed by a team at the National University of Singapore, led by Asst. Prof. Tan Swee Ching. It's essentially a transparent acrylic box that has kangkong vegetable plants growing in soil on the bottom – on top, a hydrogel panel lies beneath a solar-powered motorized cover.

The copper-based hydrogel is very absorbent, readily drawing water vapor from the cool night air while the cover is open. An integrated timer closes it at dawn, with the sun's rays subsequently heating the hydrogel through the clear cover material. The gel responds by releasing its stored water in the form of vapor, which condenses into liquid on the inside of the cover.

When that cover periodically slides open throughout the day, the condensation gets wiped off along the inside edges of the box and trickles down the insides of the walls, running into the soil. According to the scientists, the gel can absorb up to 300 times its weight in water at night. During the day, it releases that water at an hourly rate of 2.24 grams of water per gram of gel.

The research team, from left to right: Asst. Prof. Tan Swee Ching, Mr. Qu Hao, Ms. Yang Jiachen and Dr. Zhang Xueping
The research team, from left to right: Asst. Prof. Tan Swee Ching, Mr. Qu Hao, Ms. Yang Jiachen and Dr. Zhang Xueping

In fact, the hydrogel was previously tested by the Hawaii Space Exploration Analog and Simulation (HI-SEAS) research project, as a possible means of controlling humidity in greenhouses on space missions. And what's more, the released water meets World Health Organization standards for drinkability.

The team is now investigating methods of scaling the technology up for large-scale applications, which could potentially include multi-tiered, produce-growing urban rooftop setups.

Source: National University of Singapore

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4 comments
Mator
Great. I like this type of invention and research. 👍
Worzel
Having lived in Singapore, it has an almost constant humidity of 90% or more, so plenty for this device to work with. Whether it would function effectively in a dry climate, where it would be most needed is yet to be shown.
Karmudjun
Well it certainly is clear and irrefutable that the hydrogel's affinity for water vapor in the driest climates is nothing short of remarkable. I remember a different technique was used to wring potable water out of South American dry mesa terrain using a type of sail material. I just can't remember what the energy cost was for the proven dry climate capture of low vapor pressure gaseous water. That has been shown for one decade or more. Proven, irrefutable. The hydrogel should require less energy than the previous capture technology trialed in the desert, maybe it will have a greater capture rate too! Unfortunately, the Singapore trials make no comparison with previous desert air - water vapor harvesting technologies. The source information is just as sparse! But good report Ben, keep informing us of cutting edge technologies. Maybe in the future they will give real world info like actual cost, not "economical", actual anticipated daily water release, not "each 1 g releases 2.2 g water/hr (really, no time limit, just each gram releases 2.2g water per hour? Even on the Equinox that would be 26.88 grams of water/day....impossible!
Don Duncan
Perfect where desert meets ocean. The morning fog is collected.