Flow over single tube
 

I am trying to model the temperature change over a simple copper pipe using water. Basically I have a square domain to model the fluid flow over the pipe and then a tubular domain running through the middle for the copper as well as the water flowing through the tube. If I set the fluid through the pipe say at 240 K and the flow over at 300 K, turn on the energy equation and run the analysis, nothing happens with the temperature in the tube or with the flow around it.

Any ideas on why I can't get a temperature change for this?