Not an air well per se but this might be of interest. This is from Phoenix.
The secret is out. We harvest dew and frost at
the Garden Pool. It is easy to do. Since we are in an arid climate we have to wait for the air temperature to dip low enough to reach the dew point. This happens for us in wintertime, usually in the form of frost. We have a shiny metal sloped-roof that faces east. When the sun melts the frost in the morning, or if enough dew has formed, it travels down the roof in to the rain gutters. That is what you need. It is really that simple.