Field test and analysis on operation characteristics of medium-depth buried pipe heat pump heating systems

In this paper, the operation characteristics of the medium-depth buried pipe heat pump heating technology are summarized through a large number of engineering field research. The medium-depth buried pipe has the characteristics of high outlet water temperature, high heating power and long-term stable operation, which provides a high grade low temperature heat source for the heat pump system to improve its operation performance. At the same time, the medium-depth buried pipe itself has the characteristics of intermittent heat storage, which can well meet the change of building heating demand and the flexible energy use. The stepless frequency conversion heat pump unit is more suitable for matching operation with the medium-depth buried pipe, and the energy-saving and emission reduction effect is remarkable. The water system on the heat source side has the characteristics of small flow, large head, and large change of resistance with the change of flow. The research results provide key guidance for improving the heating performance of the technology.