Heat pipe vacuum tubes are absorber of solar collector,most of radiation(i.e heat)from the sun is absorbed by this sealed head

High-efficient solar vacuum tubes are made from untra-strong and heat resistant Borosilicate 3.3with a double structure.The inner tube surface is coated with an absorbant coating which adopts magnetron sputtering plating technique.It can high efficient absorpt solar radiation and reflect thermal energy of inner tube inside to keep warm.Air of the gap between two glass pipes is exhausted in order to make the gap to become vacuum space,and an aluminum flake is fixed under the bottom of the tube in order to improve vacuum degree further.A copper heat pipe is located in the centre of inner tube.Most of radiation (i.e heat) from the sun is absorbed by this sealed heat pipe.