... works even freezing -36 Solar water heaterTechnical Parameters Heat Pipe Solar Collector Spec.(mm) Φ47×1500 Φ58×1800 ... 20 / 25 / 30 Vacuum Tube Borosilicate glass, red copper heat pipe, aluminum fin Manifold Copper flow passage, PU insulation, Aluminium alloy ... , related accessories and interconnecting pieces, etc.Heat Pipe Solar Collector:1) Heat pipe solar collector for thermal collection, with a ...