Thermal modeling for the estimation of energy losses from municipal heating networks using infrared thermography

Analysis and simulation results are reported showing that there generally is a strong correlation between the thermal IR (infrared) contrast of a district heating line and its heat losses. A computer model based on the method of finite differences is described by which the temperature field and the heat flux around a buried heating line can be predicted. Algorithms are derived for the estimation of energy losses using thermal IR imagery as input data. The most promising algorithm is based on an integration of the surface temperature profile across the heating line. Under favorable conditions, it seems possible to estimate heat losses with an error (RMS) of 10 to 20% and a sensitivity of 10 to 20 W/m. The main limitations of the technique and the choice of favorable conditions for data acquisition are analyzed and discussed.<
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