... ,CE,CCC.... Heat pipe vacuum tubesHeat pipe vacuum tubes is the application to the solar industry of heat ... of heat pipe classified by in-service conditionSolar vacuum tubes specifications StructureAll-glass double-tube co-axial structureGlass materialHigh ... 1900mm 2000mm 2100mmAbsorber MaterialAluminum,copper,stainless steelAbsorptive CoatingSS-CU-AL-N/ALAbsorption Coefficientα≥0.92Emittance<8% (80°C) ...