Is PERT or PEX better for geothermal pipes?

PERT-DX800 is a medium-density polyethylene plastic with excellent and stable thermal properties that has become popular in the piping industry recently; it is a copolymer of ethylene and octene. At higher temperatures and pressures, it can exhibit long-term hydrostatic (LTHS) properties without the need for cross-linking ； It is a new material that replaces PB and cross-linked polyethylene XLPE, and is widely used in the production of various plastic composite pipes and geothermal heating pipes that require high temperatures. This type of pipe has no adverse effect on water quality in terms of odor, making it the most hygienic and environmentally friendly pipe material available today. Introduction to cross-linked polyethylene (PEX) pipes: Ordinary high-density polyethylene (HDPE and MDPE) pipes have linearly structured macromolecules; their biggest drawback is their poor heat resistance and creep resistance. Therefore, ordinary high-density polyethylene pipes are not suitable for transporting fluids at temperatures above 45°C. "\"Cross-linking\" is an important method for modifying polyethylene; by cross-linking its linear macromolecular structure, polyethylene is transformed into PEX with a three-dimensional network structure. This process **improves polyethylene’s heat resistance and creep resistance, while also enhancing its aging resistance, mechanical properties, and transparency. The higher the degree of cross-linking, the more significant these improvements become.\" It also inherits the inherent chemical resistance and flexibility of polyethylene pipes. There are three types of commercially available PEX pipes. PEXa pipes, PEXb pipes, PEXc pipes – Characteristics of PEX pipes: Excellent heat and cold resistance, with high thermal strength at high temperatures; outstanding toughness at low temperatures; does not melt when heated; superior creep resistance. Creep data serve as an important basis for product design and material selection. Compared to traditional materials such as metals, the strain behavior of plastics depends significantly on loading time and temperature. The creep properties of PEX pipes make them one of the most ideal pipe materials among common plastic pipes. Exceptional creep resistance: Creep data serve as an important basis for product design and material selection. Compared to traditional materials such as metals, the strain behavior of plastics depends significantly on loading time and temperature. The creep properties of PEX pipes make them one of the most ideal pipe materials among common plastic pipes. Semi-permanent service life: After passing tests at a temperature of 110°C, with a cyclic stress of 2.5 MPa, for 8760 hours, it can be concluded that PEX pipes have a continuous service life of 50 years at 70°C. As can be seen from the above description, PERT is a material specifically designed for geothermal pipes