This kind of project solar collector is vacuum tube collector. It is widely used on commercial project for a hotel, school or a swimming pool.
1. Economical project solar system, no need circulation pump
2. Three water tanks. Inner tank is made of 0.4mm SUS304, outer tank is 0.4mm SUS304 or color steel. 55mm polyurethane for keep the hot water warm
3. Two 500L solar collector