For low-temperature systems such as combined cooling and heating systems, a three-layer structure consisting of "PE-Xc inner tube + polyurethane insulation layer + PVC outer protective tube" is adopted. This structure has an extremely low thermal conductivity, significantly reducing heat loss during transmission and distribution and enhancing energy efficiency. At the same time, it is waterproof and moisture-proof, preventing condensation on the ceiling and ensuring efficient delivery of hot water, providing a key guarantee for the energy-saving performance of the system.