tri-target solar vacuum tube,tri-target solar evacuated tube Advantage: High pressure withstanding ability High absorption efficiency Low heat loss Stable and ageing-resistant coating Anti-freezing Workability in tough weather 10 Years warranty ISO 9001:2008 certified The absorver layer is coated with stainless steel,aluminum and copper in an environment of entire nitrogen.The selective coating is more stable with when stainless steel is added,and the absorptance is higher.Since copper is more efective than aluminum in reducing infrared conduction,heat loss is greatly cut down when copper is coated as the infrared-reflecion layer. The vacuum jacket which is of high vacuum degree is a kind of superior insulation.It reduces heat loss and protects the water in the tube from freezing. Solar evacuated glass tube can ptoduce hot water even tough water.That's why it is suitable to be used in areas and regions where is very cold or always cloudy. If you wanna get more information about our products,please contact us.Thank you.