... tank here . The characteristic of Heat Pipe Solar Collectors1) Reliable, efficient, twin-glass evacuated tubes. 2) Red copper(TU1) heat pipes, ... fuel cost.The Principle of ThermosyphonMetal Heat Pipe Solar Collector consists of a vacuum tube, a heat pipe, a metal heat ... circulation as long as the collector is heated by the sun. The details of material1. Vacuum tube: Φ58×1800mm2. Condensor: Red copper ...