Water extraction from air and desalination

Abstract

This invention is a water producer that extracts water from the air. One embodiment of the invention adiabatically compresses and heats the air. The heated air is cooled through a counter-flow heat exchanger so that it becomes supersaturated and water condenses. The air is then cooled further and passed back through the heat exchanger to recover its former heat. It then passes through an adiabatic expander to recover energy. A second embodiment utilizes a unique isothermal compressor / expander to compress the humid air isothermally so that the air becomes supersaturated with water, and the water condenses. The air is then cooled to remove the heat of condensation of the water and returned to the isothermal compressor / expander to recover energy. A third embodiment draws in humid air through a counter-flow heat exchanger to cool it down below its dew point so that water is collected. The air is then cooled adiabatically and passed back through the counter-flow heat exchanger and on to a compressor, which compresses the air back to ambient pressure and pushes the air out. These embodiments can be used to desalinate seawater, brackish water, or desiccant aqueous solutions by having a humidifier evaporate water from the liquids to make the input air to the water producer very humid.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This claims priority to and the benefit of Provisional U.S. Patent Application Serial No. 60 / 746,271, filed May 3, 2006, the entirety of which is hereby incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]The earth's atmosphere carries an enormous amount of water. At 50% relative humidity, the amount of water flowing in a 10 mile per hour wind over a farmer's square-mile farm in Kansas with a clear sky overhead amounts to 6.9 billion gallons per day. That is 21,140 acre-feet, enough to cover the farmer's land to a depth of 33 feet of water every day. The winds over the U.S. carry far more water than all the American rivers combined. Most of that water is carried back out over the oceans without being used.[0003]There are many places in the world that have a severe shortage of water, but machinery could be built to supply water from the air. Most water extraction mechanisms require a lot of energy. Some of them use refrigerati...

AI Technical Summary

Benefits of technology

[0009]An added advantage to one of the devices described below is that if solar energy is available, the solar heat can be introduced at a specific point in the cycle, and it can generate electric power, and the use of the solar energy is very efficient. This eliminates the problem of having to set up a separate engine to drive the Water Producer.

[0019]It is another object of the present invention to provide methods to effectively allow approximate isothermal compression and expansion.

Problems solved by technology

Most water extraction mechanisms require a lot of energy.

One problem is that when air is compressed adiabatically, it gets hot, and that lowers the relative humidity.

The problem with this design is that the air that is being compressed gets hot before it reaches the porous medium.

But this would mean that the device would be very slow and would take a long time to produce a gallon of water.

That will not work with their system, because if their system is isothermal, any extra heat produced by water condensation would be absorbed by the same mechanism that keeps the air isothermal.

Parenthetically, it should be noted that one of the problems with the Spletzer patent discussed above is that the water is deposited in a porous material at the end of the cylinder in which the piston is located.

Furthermore, and water clinging to the inside of the pores of the material will evaporate.

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