Ground source heat pump is an energy conversion system that uses a large amount of low-temperature heat sources stored in shallow underground soil, rocks, groundwater or other media to provide heating, air conditioning and hot water for building spaces. Ground source heat pump is by far one of the most comfortable, efficient and environmentally friendly technologies. Ground source heat pumps can be applied to central air-conditioning systems, floor heating, hot water supply and other fields in projects including office buildings, villas, schools, hotels, hospitals, etc. Among them, central air-conditioning systems are the most common.　　 Introduction to the energy-saving principle of ground source heat pump 　　 Ordinary central air-conditioning mainly achieves cooling effect through cooling tower and cooling pool in summer, and heating effect through boiler in winter. Among them, whether it is cooling in summer or heating in winter, energy consumption is very large, and the efficiency is not high. The ground-source heat pump central air-conditioning system uses the temperature of soil or rocks within tens of meters to one or two hundred meters underground to achieve cooling or heating of buildings. The temperature used by the system is generally between 15 degrees Celsius and minus 17 degrees Celsius throughout the year. It is significantly higher than the surface temperature in winter and significantly lower than the surface temperature in summer. Part of the heat collected in summer can be stored in underground soil for use in winter. Heating. Ground source heat pump air conditioning system 60%~70% of energy comes from soil, 30%~40% comes from electric energy, so it has outstanding energy saving performance.　　 Classification of ground source heat pumps 　　 Ground source heat pumps can be divided into groundwater ground source heat pumps, surface water ground source heat pumps, and underground ground source heat pumps according to the source of heat sources. Among them, the low-level heat energy of the buried pipe ground source heat pump mainly comes from the shallow underground soil, rock and other media, and the heat exchange is carried out through the circulating water of the closed circuit system of the pipeline. The resources are extremely rich, almost not restricted by the geographical location, and are very environmentally friendly and energy-saving. Therefore, the application prospect of this method is the most broad (the following content mainly introduces the underground ground source heat pump).　　Pipe products for ground source heat pump systems 　　The piping part of the ground source heat pump system mainly uses PE (PE100, PE80) pipes and PB pipes. Among them, PE pipes are widely used in many projects due to their remarkable economic efficiency. The piping part of the ground source heat pump mainly includes the main pipe (collecting pipe) connecting the heat pump unit, the buried pipe for heat exchange, and various accessories connecting the entire piping system. Supervisors 　　 Supervisors generally adopt D40-63 specifications, and some large-scale projects use supervisors around D110. The pressure level of the main pipe is generally above 1.0MPa, and the relevant dimensions of the pipe refer to the national standard of PE water supply pipe GB13663. The length of the main pipe is generally determined according to the design of the project. Sometimes due to geographical or geological conditions, the laying of the buried pipe may need to be 1 to 2 kilometers away from the building, and a longer main pipe is required.　　The supervisor generally supplies straight pipes, and special circumstances are determined by the design unit and the manufacturer through consultation.　　 In order to prevent the pipeline from freezing in winter, the main pipe needs to be buried below the frozen soil layer, and the indoor unit is connected to the ground. The part of the main pipe above the frozen soil layer generally needs to be insulated with polystyrene or rubber plastic materials. Underground pipes Underground pipes have specifications such as D16, D20, D25, D32, D40, but most of them are D25 and D32 specifications, especially D32 specifications. Since the buried depth is generally about 100 meters, the pressure level is mostly Above 1.0MPa, 1.6MPa is the most common. The relevant size requirements of buried pipes also refer to the national standard GB13663 for PE water supply pipes. Buried pipes are generally coiled, and the length is determined by engineering design requirements.