[tri8kand11700]

Yes Hello everyone, I need help and that BADLY!

I was given an Evaporator, and I have to calculate the NTUs in it. The problem is that there is not Temperature transfer in it.

Its a countercurrent Evaporator. I have two liquids, one is hot water and the 2nd is a Working-fluid. I am gonna attach a picture.
The hot water enters the Evaporator on the Outside of the Evaporator with the Temperature T3 and leaves it with the Temperature T4.
The working fluid enters the Evaporator on the inside with the Temperature T1 (in the saturated liquid state) and leaves the Evaporator with the Temperature T2 (in the saturated Vapor state).

Now I have the problem that T1 = T2 and T3 = T4, and when I calculate the Number of effectiveness I get a 0, and then when I calculate NTU I also get a 0.

Can someone please help me, because I am going slowly mad.