Are there any types of solar water heaters that do not store water in heat absorbing tubes?

Yes, solar heat absorbing tubes are generally divided into two types, namely single vacuum tubes and double vacuum tubes, but there is water in vacuum tubes, which are more commonly used in the south, and the price will be relatively lower. Double vacuum tubes It is also called double vacuum supertube. Heating is done by evaporation of the medium in the vacuum tube. The advantage is that it will. does not explode due to freezing and water expansion in winter. But the price will be a little more expensive! I hope this helps you!