Measurement and mathematical modelling of heat loss in the pipe systems of a central heat distribution network

The measurement of physical parameters conducted on a central heat distribution network was used to determine heat loss using pipe dimensional analysis. All the developed models include all relevant physical parameters which are expected to have an impact on heat loss. The interdependence of these parameters is expressed as a function of similarity criteria. When creating a mathematical model, the so-called Buckingham π theorem is used. The model consists of the dependency of only two parameters, which greatly simplifies the currently-used procedure of calculation based on heat transfer theory. The proposed way of expressing heat loss is further interpreted in the article by two simpler modifications. In the simplest variant, the interdependence of dimensionless criteria is subtracted from the original diagram. The results presented in this article are valid for a diameter 125 mm (DN125) overhead network with insulation. The scope of the model was validated for ambient temperatures of −20 to +30 °C and a transported water temperature from 40 to 70 °C.