The impact of ground heat capacity on drinking water temperature

Temperature is known to impact physical, chemical, and biological processes in Drinking Water Distribution Systems (DWDS), but it is rarely considered or modeled. This research evaluates the impact of considering a finite heat capacity for the ground, which has been assumed infinite in previous DWDS research. The aim of this work is to explore and quantify the region where the difference between considering infinite or finite heat capacity for the ground is significant, i.e., the distance over which water-ground heat transfer interaction is important. A detailed model comparison is carried out for key pipe materials, diameters, and hydraulic conditions. Temperature effects are found to exist for up to tens of kilometers (i.e., several hours) into the DWDS. Whereas the differences found were only a few degrees Celsius, this will affect all reaction rates, such as chlorine decay, and is at the start of the DWDS so will impact the entire downstream network. This work highlights the importance of considering temperature in DWDS, and in particular the finite heat capacity of the ground, in ensuring the provision of safe drinking water.