Evacuated tubes are made up of two layers of borosilicate glass, also called “pyrex”. Borosilicate glass is a strong glass that can withstand high temperature. The outer tube is transparent allowing UV rays to pass through with minimal reflection. The inner part is coated with a thermal radiation absorbing layer, aluminum nitride (AlN). This layer also reduces reflection in order to increase absorption. The two tubes are sealed at one end and the air in the gap between them is evacuated.
Vacuum space act as an insulator and once the radiation is absorbed through the evacuated tubes the heat that is generated will not escape into the atmosphere. This is similar to a common known "thermos bottle".Downlload our brochure
A heat pipe is situated within each evacuated tube engulfed by an aluminum heat fin. The tube is tightly sealed to prevent any water, dust or air from entering and affecting the performance of the heat pipe and the aluminum heat fin.
A heat pipe is an extremely efficient thermal conductor that transfers large quantities of heat via a thermal conducting fluid. A small amount of this fluid is sealed inside the heat pipe. Once the heat pipe is heated due to the absorbed solar energy the fluid inside it vaporizes and rises to the condensing zone where the heat is transferred to the water flowing through the manifold. The loss of heat causes the vapour to condense and flow back down the heat pipe where the process is once again repeated. The heat pipe is made of copper in order to maximize the heat transfer rate. It can transfer heat 10 000 times more efficient than any other heat conductor.