Linköping, Sweden, based company, Termisk Systemteknik, has developed an aircraft-based system that uses thermal imaging to monitor and maintain a city's local district heating networks. The company uses a Flir SC7600 thermal imaging camera to make the measurements.
District heating involves distributing hot water or steam from a central location to households and companies through an underground network of pipes. It can potentially help to reduce a city's carbon footprint by increasing the efficiency of heating systems throughout the city. In Scandinavia, a significant portion of the pipe networks are now quite old and starting to leak; Swedish companies are estimated to lose several million cubic metres of water a year from leaking pipes.
Thermography experts at Termisk Systemteknik mounted a Flir SC7600 on the bottom of a small plane. By flying over the city and recording the thermal images, a thermal map is produced of the entire city on which district heating leaks can be detected and located. An automatic detection system was used on the thermal data to point out leaks and other issues to the district heat maintenance teams.
The Flir SC7600 thermal imaging camera contains a cooled indium antimonide (InSb) infrared detector with a resolution of 640 x 512 pixels at a thermal sensitivity of 20mK (0.02°C). The camera proved especially useful for this application because of its high frame rate and short integration time. It was able to capture full resolution thermal images at a frame rate of 100Hz. Such high speed acquisition and short integration time proved indispensible when flying over a city at moderate speed while capturing sharp and clear thermal images.