宋伟, 倪龙, 姚杨. 热源井抽灌同井连续取/放热特性试验[J]. 农业工程学报, 2017, 33(11): 248-253. DOI: 10.11975/j.issn.1002-6819.2017.11.032
    引用本文: 宋伟, 倪龙, 姚杨. 热源井抽灌同井连续取/放热特性试验[J]. 农业工程学报, 2017, 33(11): 248-253. DOI: 10.11975/j.issn.1002-6819.2017.11.032
    Song Wei, Ni Long, Yao Yang. Experiment on characteristics of continuous heat absorption/release for pumping and recharging in same thermal well[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(11): 248-253. DOI: 10.11975/j.issn.1002-6819.2017.11.032
    Citation: Song Wei, Ni Long, Yao Yang. Experiment on characteristics of continuous heat absorption/release for pumping and recharging in same thermal well[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(11): 248-253. DOI: 10.11975/j.issn.1002-6819.2017.11.032

    热源井抽灌同井连续取/放热特性试验

    Experiment on characteristics of continuous heat absorption/release for pumping and recharging in same thermal well

    • 摘要: 针对抽灌同井连续运行特性的研究不足,利用单井循环地下换热系统砂箱试验台,以沈阳和上海2地采暖期和空调期的时间尺度为依据,分别开展了连续取热和连续放热2种运行模式下抽灌同井运行特性的试验研究。结果表明,抽灌同井在该试验条件下对取热工况更加敏感,取热比放热更为困难。在连续取热工况下,含水层在受到外界初次干扰的影响更为明显,第2个运行周期的累计取热量降幅为6个运行周期累计取热量降幅的57.1%。在热/冷负荷占优的地区,应根据建筑负荷采取辅助手段及时对含水层进行热量/冷量补给,保证热泵机组高效运行。

       

      Abstract: Abstract: Groundwater heat pump system is an ideal approach to heat and cool the building due to its attractive advantages. When using groundwater as a primary energy source in combination with heat pump, the groundwater is pumped from the pumping area, heated/cooled in the heat exchanger of the heat pump, and then reinjected into the irrigation area. Single well groundwater heat pump (SWGWHP) is a new member of groundwater heat pump, which has become increasingly popular for using because of the economic advantages. In general, SWGWHP includes standing column well (SCW), pumping & recharging well (PRW), and forced external circulation standing column well (FECSCW). Their pumping and injection pipes are placed in a same well, the low part of which is pumping water and the top part recharging water. The SCW needs to drill hole in the bedrock directly, and then most of the water circulates in the well bore and the heat exchange takes place in the well wall, while small part of water goes out of the borehole and exchanges the heat with aquifer raw water. There are some clapboards in PRW that make the thermal well divided into 3 parts, i.e. injection zone (in the top part), seal zone (in the middle part), and production zone (in the low part). The FECSCW is similar to PRW. The difference between them is that the diameter of borehole in FECSCW is larger than the one in PRW. Moreover, the gap of borehole in FECSCW is filled with sorted gravel. Through previous research on the thermal features of three kinds of thermal wells, PRW has obvious advantages in 3 kinds of SWGWHP. Because its middle partition area exists, the backwater is reinjected into the aquifer completely, while thermal transfixion occurs rarely. In view of less experimental research on continuous operation, this paper selects the PRW as the research object. According to the heating/cooling period in Shenyang and Shanghai, 2 different modes of continuous operation in PRW have been carried out using a physical simulation experimental sandbox of SWGWHP, which can accurately reflect the actual physical phenomena. In this experimental research, time of operating condition has been distributed by heating season, air-conditioning season, and recovery season, while 2 test conditions are continuous heating mode and continuous cooling mode. In the heat/cold load dominant area, the results show that the aquifer can't be restored to its original state during the natural recovery period. In continuous heating conditions of 6 cycles, the decreasing amplitude of accumulative heat absorption quantities of 6 cycles reaches 23.0%. Compared to the cooling condition, the decreasing amplitude of accumulative heat rejection quantities in 6 cycles is only 6.0%. These data show that the PRW is more sensitive in heating mode, while the heat absorption is more difficult than heat rejection. Additionally, in continuous heating condition, the aquifer is more obvious in the initial disturbance. The reduced amplitude of cumulative heat in the second operating cycle is 57.1% of all reduced amount in 6 cycles. Thus, in the heat/cold load dominant area, it is necessary to carry on the energy recharge to the aquifer in time according to the building load, in order to ensure the system in a long-term reliable operation.

       

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