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Harvesting Water with Calcium Chloride and Passive Solar Energy
Over the past week, a large percentage of Americans have realized that cooling and water accessibility are going to be major issues into the coming decades. Accessing fresh water, and being able to create it from salt water or atmospheric sources — a problem already felt in many equatorial countries for the better part of the last century — is going to become a mainstream idea in normally more temperate regions very soon.
I’ve had this idea floating around for a while, nothing earth shattering, but I really had this concept of the “moisture vaporators” in Star Wars, and imagined a device like that which could be almost like an appliance for individuals to collect fresh water, even when the humidity was very low.
Calcium Chloride (CaCl) is able to absorb large amounts of water, enough to turn into a brine. This is exploited in products like Damp*Rid to improve humid rooms and storage locations. By leaving CaCl in damp night air, we can collect moisture, creating a liquid brine. If we enclose that brine in a container, and heat it passively using the sun, the resulting water vapor can be condensed as pure distilled water. The now-dry CaCl may then be reused to collect more water. The only problem is this process is more efficient if we can seal the container while we collect the water.
