2,888 kilometres of district heating pipes lie under the streets of Copenhagen. That corresponds to the distance from Copenhagen to Rome  - and nearly all the way back again – which poses a great challenge in terms of detecting heat losses due to holes in the pipes.

That is why HOFOR - Greater Utility Copenhagen –  tested a new technology to combat the leakages in December 2016, sending drones in the sky over the Vanløse and Brønshøj/Husum districts in Copenhagen.

Equipped with a thermographic camera, the drones took around 50,000 images that were stitched together in a thermal map pinpointing unusually high temperatures in the underground, thus indicating areas with a risk of heat and water loss in the district heating pipes.

When HOFOR lays new district heating pipes in the ground, they are equipped with alarm threads, which is a newer technology that registers possible leakages, but because many of the pipes under Copenhagen are old, it is not possible to utilise it.  

The drone project was tested with high expectations, and did not disappoint according to Bo Jensen Møller, Section Chief at HOFOR:  

- Watch a video of a drone in action 

”The drones have located 44 areas with a high probability of leakages uner Vanløse and Brønshøj/Husum. We have already been on site to the first areas, which rightly so have turned out to be leakages that we are now repairing”, he explains.  

These leakages would ordinarily not have been found, or would have taken much longer to locate, because many of the pipes run beneath residential areas in people’s backyards and gardens, where it is nearly impossible to measure with handheld thermographic cameras.

”Thanks to the drone technology we gain a precise overview much faster, which enables us to repair the leakages must faster as well. This minimizes the overall heat loss and enables much better planning of maintenance of the pipe system. This reduces CO2 emissions and costs on the heating bills for consumers, says Bo Møller.

The drones will now hover over other parts of Copenhagen, starting with residential areas in Valby and the South Harbour, then Amager and Østerbro.

A number of circumstances need to be fulfilled in order to obtain useful results when using this drone technology. It must be cold and dark and not too windy, and the asphalt must not be wet. That is why HOFOR aims to complete all drone flights during spring.

 Source: HOFOR