Thermal Performance, Design, and Sustainability of Borehole Heat Exchangers within Challenging Hydrogeological Environments

总体目标是在具有挑战性的水文地质环境中推进低温地热能（埋管换热器[BHEs]）的使用和性能。两种环境被认为是：系统访问深中温异常，浅系统不连续的永久冻土。从本质上讲，这代表了地球交换系统的两个端元问题区。 现场油砂热采方案将大量能量注入地下100米的沥青储层中，使蒸汽室边缘的温度从7 - 11 ℃升高至高达200 ℃，并使储层边缘沿着升高至50 ℃。从本质上讲，这些操作无意中充当了地下热能储存系统。该项目将设计高效和可持续的闭环BHE，在水库内工作，并进行全面的能源和碳平衡评估。经济分析将支持商业和监管案例，将回收能源视为沥青提取作业的负碳（即CO2）成分。温室产业提出的模式案例中提取的热量的消耗。 低温地热应用通常限于平均地面温度为5至10 ℃或更高的地区。然而，在不连续的永久冻土区，存在使用BHE提取热量的潜力。热提取可以有效地扭转多年冻土退化和稳定基础。虽然在寒冷气候下使用BHE来满足空间供暖需求通常不经济，但在偏远地区远离柴油燃料来源的好处，同时稳定永久冻土是缓解因素。FEFLOW的BHE模拟能力将被使用，但现在使用新的piFreeze插件来模拟冻结的地面条件。 由于对温室气体排放、可持续性和高能源价格的担忧，地源地热系统正引起越来越多的关注。然而，设计方面的考虑和监管框架并没有同步推进。由于没有研究基础来支持实践，因此生态环境很少受到行业的关注。油砂油藏目前是加拿大最大的能源资产之一。然而，人们仍然对生产水库所需的温室气体排放感到担忧。一个新颖的想法是在生产结束时回收储层中剩余的热量。通过利用这种能源来支持温室产业，关闭后，将利用现有的基础设施，并为当地居民保持就业机会。在不连续的永久冻土地区使用BHE作为建筑热源可以稳定地基，并允许清洁能源取代柴油。

The overall objectives are to advance the use and performance of low temperature geothermal energy (borehole heat exchangers [BHEs]) in challenging hydrogeologic environments. Two environments are considered: systems accessing deep medium-temperature anomalies, and shallow systems in discontinuous permafrost. In essence, these represent two end-member' problematic zones for geoexchange systems. In-situ oil sands thermal recovery schemes inject a tremendous amount of energy into bitumen reservoirs 100's of metres underground, raising the temperatures from 7 - 11C to as high as 200C at the steam chamber edge, and 50C along the reservoir edge. In essence, these operations have unintentionally acted as underground thermal energy storage systems. This project will design efficient and sustainable closed loop BHEs that work within the reservoirs and perform comprehensive energy and carbon balance assessments. Economic analysis will support the business and regulatory case for considering the recycled energy to be a negative carbon (i.e. CO2) component of the bitumen extraction operations. A greenhouse industry is proposed as the model case for consumption of the extracted heat. Low temperature geothermal applications are normally limited to areas whose average ground temperatures are 5 to 10C or warmer. However, the potential exists to use BHEs to extract heat in zones of discontinuous permafrost. Heat extraction can effectively reverse permafrost degradation and stabilize foundations. While it would not normally be economical to use BHEs for space heating needs in cold climates, the benefits of moving away from diesel fuel sources in remote areas, while stabilizing permafrost are mitigating factors. FEFLOW's BHE simulation ability will be used but now with the new piFreeze plug-in to simulate freezing ground conditions. Ground source geothermal systems are drawing increased attention due to concern about greenhouse gas emissions, sustainability, and high energy prices. However, design considerations and the regulatory framework have not advanced at the same pace. Challenging environments receive little industry attention because the research base is not there to support the practice'. Oil sands reservoirs are currently one of Canada's largest energy assets. However, concerns about greenhouse gas based emissions required to produce the reservoirs remain. A novel idea is to recover the heat remaining in the reservoir at the end of production. By utilizing this energy to support a greenhouse industry, post closure, existing infrastructure will be utilized and employment opportunities will be maintained for the local population. Using BHEs as a source of building heat in regions of discontinuous permafrost could stabilize foundations and allow for a clean energy source to replace diesel.