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S.A.W.E.R.– Drinking Water from Desert Air

Published: 07. 01. 2021

The autonomous unit S.A.W.E.R. (Solar Air Water Earth Resource) generates drinking water in the dry hot climate which can be used for consumption, feeding livestock or for plants irrigation. The system getting water from air and cultivating the desert into fertile garden.

In practice, large amounts of water would be needed to make such a change. But where in the desert can one find such huge quantities of water? From the air using the Sun! Even desert air contains a small amount of water vapour. But the climate conditions of the desert do not allow for an easy extraction of water from the air with the use of a conventional cooler, that would condense the water with low temperature. That can be done in the European climate conditions, but not in a barren area suffering from water shortage.

Solar Air Water Earth Resource (S.A.W.E.R.) is composed of two systems, one for extracting water out of the desert air and the other for cultivating the desert into fertile land.

The unit works using the principle of adsorption and desorption of air humidity. Its main part is the sorption unit with a desiccant exchanger that allows for dehumidification even of air with low content of water vapor that can be found in desert conditions.

pracoviste/12116/SAWER/4-08_07_18.jpgThe unit takes the outside air in, dehumidifies it and returns the dehumidified air into the outside environment.
Extracted water molecules accumulated in desiccant are then released at high temperature to smaller amount of air to increase its humidity. High humidity from the air then condenses on the built-in cooler in the unit as liquid water. This way, it is also possible to get water in desert conditions where ordinary condensing coolers do not produce any.

The S.A.W.E.R. unit can be operated in a totally autonomous way without the need of energy from external sources. The energy for its operation is taken from the local environment: electric energy for powering the cooling unit and fans is taken from photovoltaic panels, heat for heating the air is taken from solar thermal collectors, and cold for pre-cooling the air is taken from combined photovoltaic/thermal collectors used for cooling in the nighttime. The operation is complemented with the energy storage in the form of battery repository and heat and cold storage tanks. Therefore, the S.A.W.E.R. unit is suitable for areas without any infrastructure at all.

pracoviste/12116/SAWER/Sawer_schema_EN.jpgThe S.A.W.E.R. type unit uses the total flow rate of outside air of 2000 m3/h and its average daily production is 100 liters in the dry and hot desert environment (climatic conditions of Riyadh) in autonomous operation. If the unit is connected to network, its production is approximately double. In such environment, the S.A.W.E.R. unit production of water, as compared to ordinary condensation-only units, about eight times higher.  

The system for the acquisition of water from the air, developed by the University Center of Energy Efficient Buildings and the Faculty of Mechanical Engineering of the Czech Technical University in Prague.

The University Centre for Energy Efficient Buildings (UCEEB) and the Faculty of Mechanical Engineering of the Czech Technical University in Prague are working on the development of the technology S.A.W.E.R. in cooperation with the Botanical Institute of the Academy of Sciences of the Czech Republic.

The Botanical Institute of the Academy of Sciences of the Czech Republic is developing a desert cultivation system that uses part of the obtained water for a special photobioreactor, an artificial medium used to cultivate microalgae to produce polysaccharides and retain nutrients in the water.

The S.A.W.E.R. system for the pavilion representing the Czech Republic at the EXPO 2020  world fair in Dubai. Getting water from air and cultivating the desert into fertile garden will be the central exhibition topic of the Czech pavilion.

Photogallery