Non-presurrized Solar Water Heater

The evacuated tube is made up of 2 layers of glass. The solar energy passes through the outer glass and is absorbed by the selective coating on the inner glass, thus the inner tube becomes hot. The water inside the tube is heated by the inner glass and naturally rises up into the water tank above through thermosiphon flow, and the cold water inside the water tank drops down and is heated. Therefore the water inside the water tank is heated.