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: 1230237
• 负责人: John McCartney
• 金额: $ 101万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-15 至 2015-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1230237&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 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 researchers 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 investigators to communities and policy makers to ensure wider spread implementation of this technology.SBTES systems are expected to 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可持续能源路径(SEP)计划在NSF可持续发展科学、工程和教育(SEES)计划的框架下，将支持科罗拉多大学博尔德分校的John McCartney教授和同事以及科罗拉多矿业学院的Ning Lu教授和同事的研究计划。该项目的目标是了解从太阳能电池板收集的热量的土壤钻孔储能(SBTES)的基本多物理过程、工程挑战、环境影响和实施策略。非饱和土壤的热工水力特性和相关的热、水和水蒸气耦合流动过程将被设计成一个热管，从而增强热传递。这与传统的井下或含水层热能储存系统不同，后者依靠传导或取水/注入将热量转移到地下或从地下转移。这项研究的目的是寻求能量注入SBTES系统和随后的提取直接用于建筑物供暖或发电的最佳可扩展效率。为实现这一目标，具体任务包括：(1)建造现场规模的测试设施，以评估不同钻孔配置下的热注入和回热效率；(2)评估密集仪器土壤储罐内的水、蒸汽和热流耦合过程和潜在的环境影响；(3)表征不同测试结果的非饱和土壤的非线性运移特性；(4)验证和建立可缩放的数值模型，以研究SBTES系统的长期运行、效率和环境影响，以及(5)探索提高热交换效率的工程方法。同时，还将评估住宅、社区和工业规模地下能源储存的实施战略，方法是评估政策和来自SBTES勘探性场地的用户体验。这些网站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相关的社会经济问题尚未得到充分分析。初步估计表明，与其他能源储存解决方案相比，SBTES系统的资本成本较低，可以通过节约能源来快速回收成本。预计环境影响较小，因为SBTES是闭环系统，而且地下水流动不会对包气带中的热迁移产生重大影响。该项目将有助于培养一支具有广泛技能的劳动力队伍，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。研究人员将以他们招收和留住来自不同背景的学生的记录为基础，将两所大学的学生交流和积极参与任务纳入其中，并将确定为有效培训而建立的课程轨道。成功实施SBTES系统的社区将被用作案例，形成调查人员将向社区和政策制定者提供的短期课程的基础，以确保这项技术的更广泛实施。SBTES系统有望通过将可再生热源与可持续的热能储存解决方案相结合，在减少住宅和商业建筑供暖所需的电力或天然气方面发挥重要作用。通过考虑本研究中所研究的热传递的改善，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，还可以利用热电技术(双循环发电厂)将提取的热量转化为电力，从而减少温室气体排放。SBTES系统可以在平衡太阳能热板等可再生能源技术的成本和效率方面提供关键因素，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系统具有适应不同应用的潜力，这为克服这些系统的前期成本带来的社会经济问题提供了一项重要战略。