U-tube solar collector advantages: 

 1, the vacuum tube using the new gradient - interference in selective absorbing coating and nano-coating technology, solar absorption than 0.97, the thermal emission ratio is 0.05, have been close to the theoretical limit, creating the miracle of vacuum tube technology. 
 2, the header using thicker insulation, the insulation layer is 50mm thick. 
 3, the flow channel bold to ∮ 9.25, flow more smoothly. 
 4 manufacturers using three tubes in parallel and in series connection, cable music each root canal parallel, circulation more smoothly.