Calculation of maximum length of directly-buried cooling pipeline in cooling base station

Based on the thermal balance among the allowed temperature increase of the supply water and return water when the energy efficiency of the chiller degrades, the heat transfer of the pipeline and the heat from the friction of electric motors, deduces the mathematical expression of the maximum length of the directly buried cooling pipeline in the district cooling base station. The results show that the insulation layer is needed for the directly buried pipeline in engineering applications with a thickness of 0.04 meter appropriately, which ensures a maximum pipeline length of 930 to 1 400 meters.