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Applications of several key technologies in high-temperature geothermal heat pumps: Compared with heat pump technologies that have an output temperature of 55°C or less, high-temperature geothermal heat pumps are able to achieve a heating temperature of over 60°C without raising the temperature of the low-temperature heat source (the ground), while maintaining high operational efficiency and stable performance. Generally, the following key technologies need to be addressed. Selection of compressors: The common types of compressors used in heat pump systems today include screw compressors, hermetically sealed scroll compressors, and semi-hermetically sealed piston compressors. After comparative studies on the operating characteristics of these different compressor types, semi-hermetically sealed piston compressors are generally chosen for high-temperature heat pump systems ； Selection of working fluid: Given that the maximum operating pressure of high-temperature heat pump systems is ≤25 bar, the environmentally friendly R134a is used as the refrigerant; it causes no pollution to the environment nor any damage to the ozone layer ； Design of the circulation system: Multiple independent refrigeration circulation systems are used, with a single water circulation system shared, thereby reducing the condensation temperature and pressure of the equipment ； A special heat exchange device (economizer) is added inside the equipment to enhance its operational stability ； Optimization of system control: An optimization control mode based on the average compressor operating time is adopted to ensure long-term stable high-temperature operation and extended service life of the entire unit; furthermore, the operating conditions of the high-temperature heat pump are adjusted according to the ground source temperature and the temperature of the heat source during winter.