M SERIES
These tubes relies on the Thermo siphon principle, the construction of these tubes is of dual glass tube geometry made of borosilicate glass.
They have 2 layers of glass tubes where on the inner layer an absorbent coating is added (AL-N/AL) and the outside tube is clear.
Between the 2 layers is a vacuum of 5×10-3 Pa wish acts as an insulator, so whatever energy is absorbed will not be remitted back into the atmosphere, inside the inner tube is filled with water that works on the thermo siphon principle where inside the tube itself too streams of water are created one carrying the cold water from the tank to the tube and the other carrying the hot water back into the tank in order to heat it.
T SERIES
These tubes also relies on the natural principle Thermo siphon, their construction is similar to the M-series tube as in the dual concentric glass tube geometry, but the coating on the inner tube differs where for the heat pipe it is SS-C/Cu coating, another difference is that the inner tube doesn’t contain water but it contains a heat pipe.
The working principle is:
The selective coating on the inner cover of the evacuated tubes converts solar energy into heat energy and transfers heat to the heat pipes via aluminum fins. The liquid in the heat pipe changes into vapor which rises to the condenser.
The heat then passes through the heat exchanger and the vapor becomes liquid, returning to the base of the heat pipe.
The heat conducts to the heat transfer liquid (water or water/Glycol) via a copper collector pipe.
This transference of heat into the liquid creates a continuous circulation as long as the collector is heated by the sun.