矿井开采时周围岩石中赋存大量的热能，可以将其作为热源，利用矿井充填地埋管换热系统向地面建筑物供暖，在有效降低建筑能源消耗的同时可以提高可再生能源利用率，又可以实现矿井降温，改善井下热环境。其中，如何通过充填地埋管换热系统对中深层矿井中地热高效、稳定的提取尤为重要。因此，本论文从多因素影响下系统的采热特性和运行策略两个研究点出发，对系统的采热特性进行分析。

首先，本文建立了地埋管换热器传热模型，并对网格无关性和模型准确性进行了验证。其次，采用COMSOL模拟软件以埋管管长为核心，进行多参数影响下埋管换热系统的采热特性研究，确定不同埋深（岩温）下的最佳埋管管长范围。最后，采用OGS模拟软件在被动和主动间歇运行方式下对系统运行策略进行优化研究。结果表明：

平均名义采热量随着水平埋管长度的增长呈正增益，而与平均延米采热量相反。对不同埋深（岩温）下的采热特性分析，发现岩温在30-80^oC时，建议水平埋管长度取500-800m，且在对应范围内，岩温更高时可适当增加埋管长度。对入水温度和充填体导热系数的研究，发现充填体的导热系数对系统采热特性的影响更大。因此，工程中可首先调整充填体的导热系数来强化系统采热能力。

被动和主动间歇采热均对系统采热能力有明显的提升效果。系统长期被动间歇运行时，首先，逐天间歇比可显著提高采热效率，对周围充填体温度分布影响较小。换热第十年，逐天间歇比从24:0降低至8:16时，出水温度可提高34.27%，中心截线上距管径向0.5m处充填体温度热恢复率提升2.79%。然而，逐年间歇比对出水温度变化影响较小，而对周围充填体温度影响较大。当间歇比从4:8增加至8:4时，换热第三十年后，出水温度虽下降5.39%，而年均总采热量可提升65.29%，中心截线上距管径向0.5m处温度恢复率降低了10.8%。其次，对比逐年间歇，逐天间歇更有利于充填体的热恢复，从而强化采热。因此，建议被动间歇采热选择单个间歇周期较短的运行方式。最后，更小的间歇比功耗较小，从而保证了较高的年均COP。因此，若实际工程对总采热量没有严格要求时，建议选择较小的间歇比。反之，可适当增大间歇比。

系统长期主动间歇运行下，平均出水温度和平均延米采热量均与采储比呈负相关，而总采热量和采热效率系数与采储比呈正相关。并且，由于不同采储比下泵耗相同，原则上建议选择较大的采储比来保证较高的总采热量。而由于逐天采储比下出水温度差异较大，导致采储比为12:12和16:8的运行工况下总采热量近似相等，因此建议逐天采储比选择12:12来保证较高的出水温度和总采热量。

对比长期被动间歇运行，主动间歇对采热能力的提升效果在逐天间歇时表现更显著，设置采储比/间歇比越小，提升程度越强。而被动间歇运行使得充填体热影响范围更大。将被动间歇调整为主动间歇，换热三十年后，热影响范围从68m减小至32m。当逐年采热时长为4个月时，运行方式从被动调整至主动，温度恢复率从88.92%提高至124.52%。这表明采用主动间歇运行方式不但可以提升单管的采热能力，也可以在一定的空间内增加埋管数来实现管群采热能力的大幅度提升。

The surrounding rocks in mining contain a significant amount of heat energy, which can be utilized as a heat source for heating buildings through the use of a mine filling buried pipe heat exchanger system. This system not only effectively reduces the energy consumption of buildings and improves the utilization rate of renewable energy, but also facilitates mine cooling and enhances the underground thermal environment. Efficiently and stably extracting geothermal energy in medium and deep mines through the filling buried pipe heat exchanger system is particularly crucial. Therefore, based on previous research sites, this paper analyzes the heat recovery characteristics of the system from two research perspectives: namely, the influence of multiple factors on the heat recovery characteristics and operation strategy of the system.

Firstly, the heat transfer model for a horizontal buried tube heat exchanger is established and the grid independence and accuracy of the model are verified. Secondly, COMSOL is utilized to investigate the heat recovery characteristics of the buried pipe heat exchanger system under various parameters, and to determine the optimal range of buried pipe length at different depths (rock temperature). Lastly, OGS is employed to simulate the passive and active intermittent operation modes of buried tube heat exchangers under different operational strategy ratios. The results demonstrate that:

The average nominal heat extraction increases with the increase of the length of the horizontal buried pipe, but it is opposite to the average heat extraction per meter. According to the analysis under different burial depths (rock temperature), it is found that when the rock temperature is 30-80^oC, it is recommended that the length of horizontal buried pipe should be 500-800m, and in the corresponding range, the higher the rock temperature is, the pipe length can be appropriately extended. The study on the water inlet temperature and the thermal conductivity of backfill shows that the thermal conductivity of backfill has more influence on the heat extraction performance of the system. Therefore, the thermal conductivity of the filling body can be adjusted first to strengthen the heat extraction capacity of the system.

Both passive and active intermittent heat extraction have obvious improvement effect on the heat extraction capacity of the system. When the system operates passively and intermittently for an extended period, the daily intermittent ratio can significantly enhance heat extraction efficiency while having minimal impact on the surrounding backfill distribution. In the 10th year of heat transfer, a decrease in daily intermittent ratio from 24:0 to 8:16 resulted in a 34.27% increase in outlet temperature and a 2.79% rise in thermal recovery rate of the backfill at 0.5m from the pipe diameter on the central intercept line. However, annual intermittent ratio has little effect on the outlet water temperature variation but greatly influences surrounding backfill. For instance, when increasing from 4:8 to 8:4 after 30 years of heat transfer, although effluent temperature decreased by 5.39%, total annual heat recovery increased by 65.29%, and temperature recovery rate at a distance of 0.5m from the pipe diameter on the central transect line decreased by10 .8%. Secondly, compared with the annual intermittent, the daily intermittent is more conducive to the heat extraction of the backfill, thus strengthening the heat extraction. Therefore, it is recommended to choose the operation mode of passive intermittent heat extraction with a short single period. Finally, the smaller intermittent ratio consumes less power, thus guaranteeing a higher annual COP. Therefore, if the actual project does not have strict requirements for the total heat extraction, it is recommended to choose a smaller intermittent ratio. Conversely, the intermittent ratio can be appropriately increased.

When the system operates actively and intermittently for an extended period, the average outlet water temperature and average heat extraction per meter are negatively correlated with the operation strategy ratio, while the total heat extraction and heat extraction efficiency coefficient are positively correlated with the operation strategy ratio. In addition, because the pump consumption is the same under different production and storage ratios, it is recommended to choose a larger production and storage ratio to ensure a higher total heat extraction. Since there is a large difference in outlet water temperature under the daily intermittent storage ratio, and the total heat extraction is approximately equal under the extraction and storage ratio of 12:12 and 16:8, it is recommended that the daily intermittent storage ratio of 12:12 be selected to ensure a higher outlet water temperature and total heat extraction.

Compared with long-term passive intermittent operation, the improvement effect of active intermittent operation on heat extraction capacity is more significant in daily intermittent operation, and the smaller the operation strategy ratio, the stronger the improvement degree. Secondly, passive intermittent operation makes the thermal influence range of the filling body larger. After 30 years of heat extraction, the thermal influence range is reduced from 68m to 32m. When the strategy ratio of operation is 4:8, the temperature extraction rate increases from 88.92% to 124.52%. This indicates that the active intermittent operation mode can not only improve the heat extraction capacity of a single pipe, but also greatly improve the heat extraction capacity of the pipe group by increasing the number of buried pipes in a certain space.

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