Department of Civil Engineering, Lassonde School of Engineering, York University, Canada.
Sci Total Environ. 2021 Jul 15;778:146235. doi: 10.1016/j.scitotenv.2021.146235. Epub 2021 Mar 5.
Geothermal or ground source heat pumps (GSHPs) are among the highest growing renewable energy technologies used for heating and cooling of buildings. However, despite being a well-established technology, their geo-environmental effects such as impact of the heat on the biosphere is still not thoroughly understood. This study uses FEFLOW software, to simulate heat and mass transport of a vertical closed-loop GSHP system. Transient flow and heat transport results for a multiple borehole system are presented which indicate long-term effects on subsurface temperature. Moreover, the impact of temperature change in a contaminated granular porous subsurface during remediation applications is examined. In particular, as subsurface temperatures are elevated due to geothermal heating, sorption will decrease and biodegradation rates will increase. These effects are examined in the context of contaminant transport, to evaluate the possibility of utilizing geothermal heating as a remediation strategy. The results revealed that temperature changes caused by GSHP operation can significantly enhance biodegradation of hydrocarbon contaminants. For instance, elevated subsurface temperature resulted in 97% reduction in benzene total mass, after one year of GSHP operation for a typical office building in Toronto.
地源热泵（GSHP）是用于建筑物供暖和制冷的增长最快的可再生能源技术之一。然而，尽管它是一项成熟的技术，但它对生物圈的地热环境影响，如热量对生物圈的影响，仍未得到充分理解。本研究使用 FEFLOW 软件，模拟垂直闭环 GSHP 系统的热和质量传输。给出了多钻孔系统的瞬态流动和热传输结果，表明了对地下温度的长期影响。此外，还研究了在修复应用中，受污染的粒状多孔地下环境中温度变化的影响。特别是，由于地热加热导致地下温度升高，吸附作用会减弱，生物降解速率会增加。这些影响在污染物迁移的背景下进行了研究，以评估利用地热加热作为修复策略的可能性。结果表明，GSHP 运行引起的温度变化可以显著增强碳氢化合物污染物的生物降解。例如，在多伦多的一栋典型办公楼中，经过一年的 GSHP 运行，地下温度升高导致苯总质量减少了 97%。
