Gridless Water Generation from Ambient Air

Howell John, HUJI, Faculty of Science, The Racah Institute of Physics



Cleantech, Environment,


Water, Gridless, Sustainability, Low Carbon, Circular Economy

Current development stage

TRL3 Experimental Proof of Concept


Water scarcity is a pressing global concern and the availability of clean water and sanitation is one of the United Nations’ 17 sustainable development goals. Reports show that over half of our planet’s population suffers from water shortages for at least one month a year. Air-water-generation is a compelling approach because water vapor is intrinsically renewable, local and potable. Passive methods are of immense value because they do not require power to drive water generation. Currently, maximum yields for passive devices are unacceptably low, ranging up to 0.6L/m2 a day.

Our Innovation

  • A novel device architecture for passive radiative cooling that overcomes parasitic effects and confounding functions
  • A system whereby the new theoretical upper limit for daily water generation is between 2-3 L/m2
  • The system hardware does not use external power; its carbon footprint is effectively zero


The research group has proposed a new system design that surpasses previously projected theoretical yields, by separating the radiative emitter and the dew collector. The proof-of-concept validated the model when tested under lab conditions.

The operating costs of such a device approach zero, limited to the cleaning of parts and surfaces. There are no moving parts in the final design.



There is a constant need for access to potable, low-cost and carbonless water. Technologies that can do so at local scale will be of perennial interest. Such a technology may be combined with other systems (e.g. local gardens) to provide a source of low-cost, clean water.