1.Vacuum tube
Evacuated tubes are the absorber of the solar water heater. They absorb solar energy converting it into heat for use in water heating. Each evacuated tube consists of two glass tubes made from extremely strong borosilicate glass. The outer tube is transparent allowing light rays to pass through with minimal reflection. The inner tube is coated with a special selective coating (Al-N/Al) which features excellent solar radiation absorption and minimal reflection properties. The top of the two tubes are fused together and the air contained in the space between the two layers of glass is pumped out while exposing the tube to high temperatures. This "evacuation" of the gasses forms a vacuum, which is an important factor in the performance of the evacuated tubes. The vacuum in the evacuated glass tube is less than 5¡Á10-3pa This can only be reached and maintained over a long period of time through a specialised evacuation process in production resulting in an almost total elimination of convection and conduction losses from the tube.
 2.Heat pipe
The heat pipes used in sunstar solar collectors have a boiling point of only 25¡æ . So when the heat pipe is heated above 25¡æ the water vaporizes. This vapour rapidly rises to the top of the heat pipe transferring heat. As the heat is lost at the condenser (top), the va pour condenses to form a liquid (water) and returns to the bottom of the heat pipe to once again repeat the process.
Each heat pipe is tested for heat transfer performance and exposed to 250¡æ temperatures prior to being approved for use. For this reason the copper heat pipes are relatively soft. Heat pipes that are very stiff have not been exposed to such stringent quality testing. Given this strict quality control and high copper purity, the life expectancy of the heat pipe is even longer than that of the solar tube.
3.TM70 Tube
The new evacuated heat-pipe tube is a revolutionary breakthrough in solar thermal technology as well as the symbol of a great leap in solar thermal utilization field after mankind's continuous researches year after year.
The tube has the following advantages:
1).Heat-pipe conduction,no water inside,thus it is successfully prevented from the defects of tube block and low power output caused by water fouling and deposits of mud and sand.
2).It prevents the tube from being easily broken caused by the volume expansion when the water in tube freezes in frigid season.
3).Start up quickly.Energy inside the tube can be taken out within 2 minutes under sunshine.The stagnation temperature of the heat-pipe can reach 220¡æ.
4).High efficient selective absorptive coatings and vacuum heat insulation technology ensure the tube to get higher heat output in cloudy weather and in moist area, especially in winter.
5).Solar collecting plate is installed and sealed inside the tube of high-quality borosilicate glass with 5x10-3Pa of vacuum, so it cannot be corroded event in moist area.
6).It perfectly solves the fetal defect of the common all-glass vacuum tube solar water heater, which cannot run if one of the tubes is out of work.
 
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