... collector in tubes. 1. Features compare to vacuum tube collector(1) More energy output from a unit area, less roof occupied;(2) ... pressure, better stagnation performance;(4) Graceful outline, well matched to the building;(5) Stable quality, free maintenance and long ... 4)Integrated frame design, nice outlook, stable structure, easy to install;(5)Integrated polyurethane foaming, thicken back and side ...