中深层地热地埋管供热可持续性研究

Study on heating sustainability of medium and deep geothermal buried pipe

中文关键词: 中深层地源热泵  埋管换热器  热特性  尺寸模型  影响半径

英文关键词: Deep ground source heat pump, ground heat exchanger, heat transfer characteristics, full-scale model, heat influence radius

中文摘要:

      为了研究中深层地热地埋管运行期间和热恢复过程中周围岩土温度变化趋势以及热恢复后岩土对竖直地埋管运行稳定性的影响。基于关中地区地质岩层数据，结合西咸新区中深层地热地埋管供暖系统实际工程应用，利用有限元仿真软件模拟分析了中深层地埋管换热器对周围岩土影响规律。结果表明: 四个月的取暖运行，在岩土上层，由于流体温度较高出现逆向换热区；在岩土下层，温度随着深度的增加降幅较大，并且在深度方向表现为线性增势；在不考虑地下水渗流的情况下，岩土取热后经过八个月的热恢复，恢复后最大温差为3.02℃，恢复后平均温差为1.30℃。岩土热恢复温差对地埋管的长期运行无显著影响，可长期持续稳定运行。实践表明，由于地层结构、地层压力、放射性衰变、地层导热等多方面因素的影响，2 000 m以下地层温度恢复迅速，并未出现明显的温度衰减，充分体现了地球恒温体的特性。

英文摘要:

      In order to study the temperature change trend of surrounding rock and soil during the operation and thermal recovery of medium and deep geo-thermal buried pipe, and the influence of rock and soil on the operation stability of vertical buried pipe after thermal recovery. Based on the geo-logical strata data of Guanzhong area, combined with the practical engineering application of the middle and deep geothermal pipe heating system in Xixian New District, this paper uses the finite element simulation software to simulate and analyze the influence of the middle and deep geo-thermal pipe heat exchanger on the surrounding rock and soil. The results show that after four months of heating operation, the reverse heat trans-fer zone appears in the upper layer of rock and soil due to the high temperature of fluid; in the lower layer of rock and soil, the temperature de-creases greatly with the increase of depth, and shows a linear increasing trend in the depth di-rection; without considering the groundwater seepage, after eight months of heat recovery, the maximum temperature difference after recovery is 3.02 ℃, and the maximum temperature differ-ence after recovery is 3.02 ℃ , the average temperature difference is 1.30 ℃. The temperature difference of thermal recovery between rock and soil has no significant effect on the long-term operation of buried pipe, which can be operated continuously and stably for a long time. Practice shows that due to the influence of formation structure, formation pressure, radioactive decay, formation heat conduction and other factors, the actual formation temperature below 2000m re-covers rapidly without obvious temperature decay, which fully reflects the characteristics of the earth"s thermostat.