working principle:
The selective coating on the inner cover of the evacuated tubes converts solar energy into heat energy and water in evacuated tubes absorbs the heat. According to temperature rises along with density drops, and weight goes down, hot water will go up to exchange with cold water in tank. In this way, the temperature of the water in tank goes up.

Specifications:

Model NO.	SBT-NOP05	Tank diameter	420∕460 mm
Inner Tank Materia & Thickness	Imported SUS304 2B Stainless steel ;	Outer tank Materia & thickness	Galvanized steel∕ stainless steel
Bracket material & thickness	Galvanized steel	Heat insulation layer Materia & thicknessl	Imported polyurethane foam 50mm
Size of Vacuum Tube	47×1500mm∕58×1800mm	Qty of Vacuum Tube	18∕20∕24pcs
capacity	110,130,155,200L	warranty	3 years for whole system