... Solar Keymark. 2.24mm heat pipe 3.Nick coating heat pipe 4.working pressure :0.6Mpa 5.Made in China solar water heating ... systemHeat pipe solar collector, solar collector, solar thermal panel, solar water heater system, 1) ... typeXianke XKPC58-15/20/25constructionVacuum tube solar collectorno. of collector pipes15,20,25tube ... wool insulation solar energy heating system