St. John Tradewinds News

Turning Sunshine into Water

I am constantly looking for new and exciting sustainable living products to use here in the islands. A few weeks ago, I wrote about the Humless battery system that you can use as a backup power device or as a solar-powered off-grid battery system.

Lately I have been reviewing a product called SunToWater which turns air into water—no kidding!
It is kind of like a dehumidifier, but much more efficient. The water it produces is distilled drinking water. It has been approved by the EPA and the FDC for portable [do you mean “potable” here?] water systems.

Here is how it works, in three stages. First, absorption: Small fans blow air over salty materials inside the unit. The salt absorbs up to 6 times its weight in water. The end result is the system collecting up to 40 to 100 gallons per day.

The second stage is extraction. The water generator uses the sun’s heat to bake the water out of the salt and into a closed loop of hot humid air. The hot air is then funneled through a condenser that extracts the water within it. This water then condenses into a collection tank as pure distilled water, ready to use in your garden or swimming pool. The cycle can repeat itself multiple times a day.

For drinking water, the SunToWater units go through a third stage—remineralization. When we sweat, our bodies lose minerals we need, such as calcium, sodium, and potassium. Distilled or reverse osmosis water does not contain these important minerals, which also help us to absorb drinking water better. This process adds important minerals back into the water, making it good for drinking.

The water can also be collected and saved for later use during a natural disaster or other emergency.

Each water generator can be operated off-grid using solar power. SunToWater consumes about 510 watts per hour of operation. You would need about fifteen 210-watt solar panels to run the water generator daily, along with two solar thermal units.

The downside is that they are not cheap. The current price tag is around $10,000, although the unit carries a ten-year warranty. Let’s do the math.

You will be making water for your house daily, so say you make 70 gallons a day, 490 gallons a week, and 1,960 gallons in a month. That equals 23,560 gallons in a year, equivalent to almost six 4,000-gallon truckloads of water at $400 to $450 per load. Buying that much water would cost about $2,500 annually, so in four years, a SunToWater unit would pay itself off.

These systems can be stacked, so if you need a lot of water, you could double or even triple your production. Then your pool would be full, your plants would be green, and you would not have to do rain dances during dry season!

For a greener tomorrow,
Dan Boyd
Lovango Cay

Dan Boyd of Island Solar is a Virgin Islands Energy Office authorized vendor. For more information, call Boyd on his cell phone at 340-626-9685 or by email at islandsolarvi@gmail.com.