HI, I’m trying to simulate a heat exchanger coil immersed in a big tube with hot air flowing in it. In the coil flow water that inlet at 15 °C. My problem is that after calculations, the water does not change in temperature remaining it in 15 °C as can you seen with blue pipe lines. However hot air change his temperature (red lines). Another problem is that blue pipe lines goes just up to the middle of the coil.
Have anybody an idea what’s going on?, I’ll be grateful for any comments.