Solar hot water project, solar water heaters

1) Collector channel: Stainesssteel
2) Collector crust: PFDV
3) Tube with 58mm dim, 1.8m length or 47mm dim, and 1.5m length
4) Water capacity: 150L / 200L / 300L
7) Heat preservation: 72h - 80h
8) Hail resistance: 25mm