This will definatly heat the water in the pipe, if you want to heat the whole tinaco, add a small pump to circulate through your collecter.
depends on the amount of hot water you want, if it is for a shower days end for one person, well just increase the diameter and length of the collector tubing, 1" tubing, each length of tube 19 ft. long holds about 3/4 gallon of water.
So figure out how much water you need and go from there.
The water coming out of your collector can reach 190 degree so be careful and best to used CPVC, cost more but better than having a PVC collecter come apart on the roof.
g'luck