Calculating Solar Water Heating Efficiency

[Solar]

Is there anyone out there that can help me answer a question I have related to solar heating of water.

- There is a 1" diameter x 4' long glass tube filled with water having an input temperature of 250F.

- There is a 2" diameter tube surrounding it, 4' long, filled with water coming from the opposite direction at a temperature of 40F.

- The Flow rate is 1 gal/min.

- I have 100 gal tank.

How long before the water reaches 80F?

For the sake of simplicity let's assume the sun shinning 24 hours a day.

Any help answering this question would be greatly appreciated.

 

[eaboujaoudeh]

have you tried some kind of solution?

 

[Solar]

A solution is what I am looking for.

As it has been a while since I am out of engineering school, and have no ready access to the calculations, I was hoping for a little help.