31.72 Fresh water from the sea (Sunwater Company solar stills installations). Heat from the sun, passing through the sloping glass cover, warms the salt water. Moisture vapor rises, condenses on che glass, and runs down inot a collection trough. At the outlet of the stills, the fresh water is drained by the small flexible tubes into a collection pipe, shown running down to lower left. The four large tubes allow some brine to overflow each day, automatically cleaning out salts. The stills do not need to be opened for cleaning.