I have gathered experimental data regarding this heat transfer problem. Unfortunately right now there is no simple way to measure discharge water temperature. On the theoretical approach developed on post # 10 of abovementioned thread, a water temperature increase of 50 °C was considered. Please help me with the same numerical development, but now for a 25 °C water temperature increase. Question: In this case, for the same steel considerations, the water flow is going to be twice as the one for 50 °C, which was 4.6 liters/sec? If not, what is going to be the amount of water flow? Thanks.