Supervision of service pipes in district heating networks

District heating (DH) systems supply heat to consumers in urban areas via dense pipe networks that carry heat energy using water as the transport medium. The largest assets for most district heating companies are bound to these pipe networks. Therefore, supervising the quality of these pipes is of great interest to district heating companies. The quality of the main pipe grid is typically supervised by advanced sensor wires built into the pipes. However, the service pipes connecting the consumers to the main pipes are typically not supervised at all. This paper proposes a novel approach that is able to detect the quality of the service pipes and thereby enable better maintenance of the network. The proposed approach uses data from smart meters already installed for billing purposes. Using this data in a Kalman filter, heat loss parameters are estimated for individual service pipes in the different segments of the district heating network. The proposed Kalman filter does not use information about the network parameters such as pipe sizes and types, but only data from the smart meters in the network segment under consideration. The proposed approach is tested on two segments of the district heating network in Randers, Denmark. These tests show that the approach was able to pinpoint the service pipes in the considered network segment that had quality issues related to the service pipe insulation.