Validation of STM+ model with heat transport measurements of ICAIR test facility

This report contains a memo (Section 3) that describes a validation study of the soil temperature model STM+ with temperature measurements from the ICAIR experimental facility of the University of Sheffield. The memo was quality controlled by TNO and its material is to be included in a peer reviewed paper (Van Esch & Van Summeren, in preparation). For a more detailed contextualization (that falls outside the scope of this report) the reader is referred to Blokker & Pan (2022) and Blokker & Pan (in preparation). As a help to the reader, a succinct introduction to the main concepts is given in Section 2.
Dutch drinking water companies are legally obliged to distribute drinking water at the customers’ tap at a maximum temperature of 25 oC. To meet this requirement in the future is expected to become more difficult because of progressive climate change, urbanization, and a denser subsurface infrastructure linked to the energy transition. Within the TKI-project ENGINE, two numerical models were concurrently developed for the prediction of drinking water temperatures in the distribution network: the soil temperature model STM+ (Van Esch, 2022) and water temperature model WTM+ (Blokker & Pan, 2022).