Optimization of Insulation Arrangement Parameters and Technical-Economic Evaluation of Inner Pipe in Deep Borehole Heat Exchanger

Promoting the development of geothermal energy utilization technology is of great significance for ensuring national energy and resource security, building a clean, low-carbon, safe and efficient energy system, and achieving carbon neutrality goals. For deep borehole heat exchangers(DBHE) technology, installing heat exchanger inner pipes with better thermal insulation performance will bring higher buried pipe outlet water temperature, thereby improving the operating energy efficiency of medium-deep buried pipe geothermal heating systems. However, whether the installation of high-insulation inner pipes is necessary for the gain in system energy efficiency compared with the additional cost it consumes still requires a comprehensive and comprehensive energy efficiency economic analysis. This paper conducts an energy efficiency evaluation on the cost per unit of heat provided throughout the life cycle of different DBHE heating systems, and finally proposes design recommendations with practical engineering application value for the setting of the inner pipe insulation layer length.