SEP Collaborative: Pathways to Scalable, Efficient and Sustainable Soil Borehole Thermal Energy Storage Systems

SEP 协作：可扩展、高效和可持续的土壤钻孔热能存储系统之路

• 批准号: 1230544
• 负责人: Ning Lu
• 金额: $ 89万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-15 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1230544&HistoricalAwards=false
• 关键词: SEP; Collaborative; Pathways; Scalable; Efficient

The NSF Sustainable Energy pathways (SEP) Program, under the umbrella of the NSF Science, Engineering and Education for Sustainability (SEES) initiative, will support the research program of Prof. John McCartney and co-workers at the University of Colorado at Boulder, and Prof. Ning Lu and co-workers at the Colorado School of Mines. The goal of this project is to understand the fundamental multi-physics processes, engineering challenges, environmental impacts, and implementation strategies for soil borehole thermal energy storage (SBTES) of heat collected from solar-thermal panels. The thermo-hydraulic properties of unsaturated soils and associated coupled heat, water, and vapor flow processes will be engineered to form a heat pipe, enhancing heat transfer. This is a transformative departure from conventional borehole or aquifer thermal energy storage systems, which rely on conduction or water extraction/injection to transfer heat into or from the subsurface. The objective of this research is to seek the optimum scalable efficiency of energy injection into SBTES systems and subsequent extraction for direct use in building heating or electricity generation. To reach this objective, specific tasks include: (1) constructing a field-scale test facility to evaluate the efficiency of heat injection and withdrawal for different borehole configurations, (2) evaluating coupled water, vapor and heat flow processes and potential environmental impacts within densely-instrumented soil tanks, (3) characterizing the nonlinear transport properties of unsaturated soils from the different tests, (4) validation and establishment of a scalable numerical model to examine the long-term operation, efficiency, and environmental impact of SBTES systems, and (5) exploration of engineering approaches to enhance the heat exchange efficiency. A parallel effort will be to assess implementation strategies for residential-, community-, and industrial-scale subsurface energy storage through evaluation of policies and user experience from exploratory SBTES sites. These sites have established high efficiencies of energy recovery, but usage trends, barriers to implementation, or socio-economic issues related to different policy strategies have not been fully analyzed. Preliminary estimates indicate that SBTES systems have low capital cost compared to other energy storage solutions, permitting rapid cost recovery through energy savings. Low environmental impact is expected because SBTES are closed-loop systems and because groundwater flow will not significantly affect thermal migration in the vadose zone. This project will contribute to generation of a workforce with a broad set of skills that can be applied to emerging renewable energy technologies, including hydrology, civil engineering, thermodynamics, environmental impact analyses, and energy policy. The PIs will build upon their track records of recruiting and retaining students from diverse backgrounds, will incorporate student exchange and active participation in tasks at both universities, and will define tracks established courses for effective training. Communities which have successfully implemented SBTES systems will be used as case histories, forming the basis of short courses which will be given by the PIs to communities and policy makers to ensure wider spread implementation of this technology.SBTES systems are expected to be play an important role in reducing the amount of electricity or natural gas required to heat residential and commercial buildings by integrating renewable heat sources with a sustainable thermal energy storage solution. By considering the improvements in heat transfer investigated in this research, the efficiency of energy recovery can be improved to provide scalable, sustainable direct use heating for communities. In addition, in some cases extracted heat may also be converted into electricity using thermal-electricity technologies (binary cycle power plants), reducing greenhouse gas emissions. SBTES systems could provide a key element in balancing the cost and efficiency of renewable energy technologies such as solar-thermal panels, influencing the fate of these technologies. Although these energy sources are renewable, energy is often generated at times when it is not necessary or in locations far from where it is needed. SBTES systems can be implemented in nearly any location in the US to provide a sustainable storage solution. The potential for SBTES systems to be scaled to different applications provides an important strategy for overcoming socio-economic concerns with the up-front costs of these systems.

NSF可持续能源途径（SEP）计划，在NSF科学，工程和教育可持续发展（SEES）倡议的保护伞下，将支持约翰·麦卡特尼教授和同事在博尔德的科罗拉多大学，宁卢教授和同事在科罗拉多矿业学院的研究计划。该项目的目标是了解基本的多物理过程，工程挑战，环境影响和土壤钻孔热能储存（SBTES）从太阳能热板收集的热量的实施策略。非饱和土壤的热工水力特性和相关的耦合热，水和蒸汽流动过程将被设计成热管，增强传热。这是对传统钻孔或含水层热能储存系统的变革性偏离，传统钻孔或含水层热能储存系统依赖于传导或水提取/注入来将热量传递到地下或从地下传递热量。本研究的目的是寻求最佳的可扩展效率的能量注入SBTES系统和随后的提取直接用于建筑供暖或发电。为实现这一目标，具体任务包括：（1）建造一个现场规模的试验设备，以评估不同钻孔结构的热注入和热回收效率，（2）评估密集仪器化土壤槽内耦合的水、蒸汽和热流过程以及潜在的环境影响，（3）从不同试验中表征非饱和土壤的非线性输运特性，（4）验证和建立可扩展的数值模型，以检查SBTES系统的长期操作、效率和环境影响;（5）探索提高热交换效率的工程方法。一个平行的努力将是通过评估政策和探索SBTES站点的用户体验来评估住宅，社区和工业规模地下储能的实施策略。这些地点已经建立了高效率的能源回收，但使用趋势，实施障碍或与不同政策战略有关的社会经济问题尚未得到充分分析。初步估计表明，SBTES系统与其他储能解决方案相比，资本成本较低，可以通过节能快速收回成本。预计对环境的影响很小，因为SBTES是闭环系统，而且地下水流不会对包气带的热迁移产生重大影响。该项目将有助于培养一批具有广泛技能的劳动力，这些技能可应用于新兴的可再生能源技术，包括水文学、土木工程、热力学、环境影响分析和能源政策。PI将建立在他们招募和留住来自不同背景的学生的记录基础上，将在两所大学的任务中纳入学生交流和积极参与，并将定义有效培训的轨道既定课程。成功实施SBTES系统的社区将被用作案例历史，形成短期课程的基础，这些课程将由PI向社区和政策制定者提供，以确保更广泛地实施这项技术。SBTES系统预计将在减少住宅和商业建筑供暖所需的电力或天然气量方面发挥重要作用，可持续的热能储存解决方案。通过考虑本研究中研究的传热改进，可以提高能量回收的效率，为社区提供可扩展的，可持续的直接使用供暖。此外，在某些情况下，提取的热量也可以使用热电技术（双循环发电厂）转化为电力，减少温室气体排放。SBTES系统可为平衡太阳能热板等可再生能源技术的成本和效率提供关键要素，影响这些技术的命运。虽然这些能源是可再生的，但能源往往是在不必要的时候或在远离需要的地方产生的。SBTES系统可以在美国几乎任何地方实施，以提供可持续的存储解决方案。SBTES系统有可能按比例扩大到不同的应用，这为克服社会经济对这些系统前期费用的关切提供了一个重要战略。