99600c1d_Collector___Solar_Water_Heater__Evacuated_Tube_Collector
[S.No] 13 [Flat Plate Collector] Old technology at higher prices [Evacuated Tube Collector] 
Advanced technology at competitive prices that is System Cost per unit water is low.
Comparison between Evacuated Tube Collector & Flat Plate Collector - Solar Water Heater
Evacuated Tube Collector