Wa­ter out of Desert air

Technowize Magazine - - Haute Money -

From Cal­i­for­nia to sub-sa­ha­ran Africa, we’re fac­ing a global wa­ter scarcity. Re­ceiv­ing less than 1cm of rain an­nu­ally and with wa­ter re­sources un­der threat, Peru’s cap­i­tal city Lima has had to get cre­ative at high al­ti­tudes where mu­nic­i­pal wa­ter de­part­ments can­not build reser­voirs. The Peru­vians with­out wa­ter move­ment has built vast nets to trap the thick sea fog and mist that reg­u­larly cov­ers hilly land­scape of Lima to pro­vide up to 400,000 liters of fresh wa­ter to the re­gion. In re­gions where it doesn’t rain much, nor are there many fresh­wa­ter sources – a sit­u­a­tion even more crit­i­cal as ur­ban pop­u­la­tions ex­pand rapidly – en­vi­ron­men­tal in­no­va­tors are con­quer­ing the cri­sis, re­source­fully, one step at a time.

A team of re­searchers at MIT and the Univer­sity of Cal­i­for­nia, Berke­ley have de­vel­oped a so­lar-pow­ered de­vice that can wring wa­ter from the desert air. The de­vice works at low power in arid con­di­tions, which means it could help re­mote desert com­mu­ni­ties with­out con­stant ac­cess to drink­ing wa­ter.

The new de­vice works like a de­hu­mid­i­fier, .i.e. it turns ex­cess wa­ter va­por in the air into liq­uid wa­ter. In­stead of us­ing elec­tric­ity, the wa­ter har­vester in the de­vice uses heat from the sun and a new ma­te­rial called an MOF (Metal­lic-or­ganic Frame­work). The ma­te­rial, MOF has a large sur­face area and pores that can be cus­tom­ized to cap­ture h2o mol­e­cules. The heat from the sun con­verts the h2o mol­e­cules into va­por, al­low­ing them to rise out of MOF’S pores and into the de­vice, which is a clear acrylic en­clo­sure. The cube houses a con­denser at the bot­tom of the ves­sel, di­rect­ing the wa­ter mol­e­cules

into a cham­ber be­low in which drink­ing wa­ter can be stores.

In dri­est parts of the world like the Sa­hara, the de­vice can pull 2.8 liters of wa­ter from the air over a 12 hour span. The so­lar-pow­ered de­vice could be used to help over 4 bil­lion peo­ple glob­ally who suf­fer from acute wa­ter short­age.

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