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Air humidity, an unlimited renewable natural resource, is available to all mankind, except in few extreme climatic regions where the temperature is bellow 4oC or extreme arid zone. One cubic kilometer of air contains 10 to 40 tones of life-giving water. Nature continually recharges the atmosphere with humidity by evaporation from the world’s oceans, seas and fresh water bodies. Cost effective adsorption of atmospheric humidity and the use of heat to recover potable water, even in arid regions, is the backbone of the EWA Technologies Group’s state of the art patented technology that works hand-in-hand with Mother Nature.
The EWA technology is based on capturing of the air humidity and releasing this humidity as liquid water. The EWA technology is composed of three main stages:
1. Adsorption of air humidity
2. Desorption of the absorbed water
3. Condensation
In the first stage, the humidity is removed from the air using desiccation material. Since the absorption of the humidity is an exogenic process (involves heat release), the humidity absorption occurs spontaneously, and only minimal energy consumption (electricity) is required to allow the air to flow through the absorbing unit. The absorption unit was designed in a way that it adsorbs only the humidity from the air, and the dry air with any pollutants, including particles, gases and microorganisms is being thrown out back to the atmosphere without influencing the water quality. As a result of this selective absorption process no water treatment is required.
The release of the water from the desiccant involves wind drying, heating, and vacuum, as this combination enables the release of the water from the desiccant by using moderate heat and low energy consumption. Steams at relatively low temperature are spontaneously condensed, while cooling allows acceleration of the condensation process and preservation of the heat energy in order to minimized energy losses.
For minimal energy consumption, the combined three processes are integrated with: a) sophisticated airflow unit; b) pressure control unit; and c) coupling between the heat and cold process.. Furthermore, a pressure controlling valve, for the airflow and heat recovery control, allows condensation of the steams with minimal heat loss and preservation up to 80% of the energy consumption.
The absorption in the first stage of the process is the key element, which allows the technology to utilized ambient air even with very low Relative Humidity (RH) of about 10% or absolute humidity of 5g/cubic air. The desiccants selected for use in the EWA Technology enable operation at temperature range between 4 to 45oC.
Only minor electricity consumption is required, while the required energy is heat energy. Combining of residual (waste) or solar heat sources allows producing water at a cost of about US$0.5/ cubic meter of water (based on US energy prices).
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