Abstract: Method and apparatus for abstracting water from air wherein in a first phase of a recurring cycle a stream of cool, moist air from the atmosphere first cools a first heat storage condenser (1) and then humidifies a hygroscopic medium (14); in a second phase a stream of warm air additionally heated by solar radiation expels moisture from the hygroscopic medium and carries the moisture into said first heat storage condenser (1) where it condenses, releasing condensation heat, and drains away; in a third phase another stream of cool, moist air from the atmosphere first cools a second heat storage condenser (2) and then rehumidifies the hygroscopic medium, and in a fourth phase another stream of warm air heated by solar energy again expels the moisture from the hygroscopic medium and carries the moisture to said second heat storage condenser where it condenses and drains away, and wherein the warm air streams of the second and fourth phases, are preheated using the heat of condensation picked up by the said secon