... glass 3.37) Solar working station8) With heat pipe: anti-freezing > -35 degrees centigrade9) Water capacity: 150L, 200L, 250L, 300L, 500L ... Thickness,1.8mm,Insulating layer,compressed rock woolHeat Pipe pure red copper TU1+water,transfer power>=150W,Working pressure,4Mpa,welding ... boron and silicon content 3.3,Structure,Gradual change SS-AL-Nx/Cu selective absorption coating,Vacuum Degree,P<=5* ...