Heat loss testing and calculation method of heating pipes with temperature fluctuations

Thermal insulation of heating pipes is the main measure to cut down the heat loss during transferring. A thermal insulation test on district heating pipes is necessary in order to evaluate the insulation situation. Studies the effect of heat source temperature fluctuations on thermal insulation test of directburied heating pipes and develops a method to test and calculate the heat loss of heating pipes with heat source temperature fluctuations. Using test data of three pipe sections of a primary pipeline in Daqing City, calculates the heat flux outside the pipe insulation with or without considering the heat source unsteady characteristics, as well as their relative errors. The maximum relative errors of three pipe sections are 555.9%，419.6% and 88.4%, respectively. The results show that heat source temperature fluctuations have a great effect on the thermal insulation test of directburied pipes.