The brine output water
is depressurized as it runs through the output section of the Clark pump. The energy recovered during the depressurization is used to assist in the pressurization of the input water
, thus saving power. Here is an animated gif image from the Spectra website that illustrates how it is done:
The Spectra website is: http://www.spectrawatermakers.com/index.html
I'm far from an expert on this, but I do have a Spectra watermaker
on VALIS, and it does indeed put out almost one gallon of fresh water per Amp-Hour (at 12V). This is about half the power consumption
of the earlier generation of DC watermakers. There are one or two other companies who now have systems with comparable efficiency.