Drones-based Thermography of Heat Distribution Networks
|Bearbeitung:||A. Sledz, J. Unger|
|Laufzeit:||2018 - 2019|
|Förderung durch:||AiF (Forschungsnetzwerk Mittelstand) / BMWi (Bundeministerium für Wirtschaft und Energie)|
In cooperation with: Fernwärme Forschungsinstitut Hannover (FFI) and industry partners like Enercity.
District heating systems distribute heat, which often is generated as waste heat during the pro-duction of electricity. For the integration of renewable heat sources, district heating networks are required to have a high degree of flexibility, especially in case of low-temperature heat distribu-tion. The high technological relevance is faced by high costs for the construction, maintenance and repair of heat distribution networks.
Today’s maintenance strategy is based on a statistical assessment of the state of damage of the networks. Relevant pipeline sections must be gradually taken out of operation and emptied. This can be remedied by airborne thermal infrared imaging of heating networks that avoids interfer-ence with the operating process. This technology makes it possible to visualize temperature dif-ferences of a surface. Temperature anomalies indicate leaking district heating water and there-fore damage to the district heating system.
Currently, airborne thermal flights can only be carried out efficiently over a large area with air-planes or helicopters and are limited due to cost considerations and high planning effort in par-ticular for small-scale networks.
In this context, the use of Unmanned Aerial Systems (UAS) as a flexible and low-cost platform equipped with a thermal sensor is under investigation to detect the condition and further ageing of these networks. Thermal data acquisition using the UAS is followed by automated thermal mapping. This task is split into two steps that are investigated: (i) the photogrammetric processing of the images and (ii) the description of the state of the heat supply network including possible changes and identification of anomalies by means of image analysis methods.
Figure 1 shows intermediate results of a test flight performed in the park near Nienburger Street above the bike lane in the park where a heating pipe (HBK – V500) is installed. Approximately 200 metres of the road where covered by the flight.
Figure 1: Thermal orthophoto. Left upper: thermal orthophoto with GIS street overlay. Left bottom: Optical (RGB camera) orthophoto with GIS street overlay. Right: thermal orthophoto with pipe and anomalies detection.