Harvesting drinking water from the air with the power of space

Obtaining fresh drinking water from the air has been very energy intensive for a long time. Researchers at ETH Zurich have now invented a currentless technology that uses the cooling of space for this.

The new device essentially consists of a specially coated pane of glass that both reflects solar radiation and radiates its own heat into space via the atmosphere. As a result, it cools down to 15 degrees Celsius below the ambient temperature. On the underside of this disk, water vapor from the air condenses to form water. I have published a  dew point  calculator for this.

The Swiss researchers want to bring this technology to the south. It would be ideal to propagate such radiative cooling. So not only fields could be irrigated with water. At the same time, the fields could be cooled by up to 15 ° C, thus ensuring a good harvest. The heat stress is already causing enormous crop failures.

It’s also a bit of a moral obligation, because our wealth also comes from burning fossil fuels. However, the rising temperatures are increasingly affecting the poorer south. These radiation coolers represent a CO2 compensation, as the effect of the CO2 can be compensated in this way.

Relieving women from the burden of collecting water by providing a faucet for every household could enable them to contribute 122 million additional working days per year to the global economy

Women and girls can also benefit from this, as drinking water often involves a considerable amount of work in the south. Making southern communities resilient to heat waves and slowing down refugee movements has tremendous benefits, and one dollar invested in water resilience can translate into a return of $ 21, as detailed in the  FT article  .

If you would like to support this and other solar radiation management techniques, please contact me  .

Tautemperatur berechnen[Quelle][Zero Mass Water Review]

Td = 243.12 * A / (17.62 – A)


A = Log(RH / 100) / Log(2.718282) + (17.62 * Ta / (243.12 + Ta))

RH = relative humidity (%)

Ta = air temperature (degrees celsius)

Td = dew point (degrees Celsius)

1 m³ air cooling 1° Celcius is about 38 BTU/hr or 11 Watt(1 BTU/hr = 3.412141633 Watt)

Ta = air temperature (degrees celsius)

Relative Feuchte



T/(°C) XH20 (abs) rH Beladung bei 100 % rH
-20 0,0010 100% 0,75 g(H2O)/m3(Luft)
-15 0,0016 100% 1,2 g(H2O)/m3(Luft)
-10 0,0025 100% 1,9 g(H2O)/m3(Luft)
– 5 0,0040 100% 3,0 g(H2O)/m3(Luft)
0 0,0060 100% 4,5 g(H2O)/m3(Luft)
5 0,0086 100% 6,4 g(H2O)/m3(Luft)
10 0,0121 100% 9,1 g(H2O)/m3(Luft)
15 0,0168 100% 12,6 g(H2O)/m3(Luft)
20 0,0230 100% 17,5 g(H2O)/m3(Luft)
25 0,0313 100% 23,5 g(H2O)/m3(Luft)
30 0,0418 100% 31,4 g(H2O)/m3(Luft)
35 0,0555 100% 41,6 g(H2O)/m3(Luft)
40 0,0728 100% 54,6 g(H2O)/m3(Luft)

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