Monitoring heat losses in a heating pipeline model using distributed temperature sensing

We demonstrate the application of distributed fiber optic temperature sensing based on optical frequency-domain reflectometry (OFDR) for the monitoring of the thermal behavior of a model of a partially buried heating pipeline and for the estimation of the heat losses in said pipeline. To do so, we continuously measured the temperature distributions in a test rig mimicking a water heating pipe after applying a temperature step change at the pipe inlet. The measurements were carried out using a commercially available OFDR system with a spatial resolution of 2.6 mm and a temperature resolution of 0.1 °C. The distributed temperature measurements allowed obtaining the time evolution of the heat losses in the pipe sections located in air and buried in soil. These experimental results serve the validation of the thermal and fluid dynamics simulations carried out using COMSOL Multiphysics^®.