RAPID: Distributed Temperature Instrumentation for Performance Assessment and Long-Term Implications of an Unconventionally Deep Geothermal Exchange Well

RAPID：分布式温度仪器，用于非常规深层地热交换井的性能评估和长期影响

• 批准号: 1317315
• 负责人: William Likos
• 金额: $ 6.5万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-15 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1317315&HistoricalAwards=false
• 关键词: RAPID; Distributed; Temperature; Instrumentation; Performance

The objective of this project is to install a comprehensive suite of fiber optic (FO) distributed temperature sensing (DTS) instrumentation to obtain short- and long-term measurements of temperature and heat flux profiles in an unconventionally deep (~300 m) geothermal ground source heat pump (GSHP) system currently being constructed in Wisconsin. Construction of a single, but very deep, exchange well offers potential advantages over conventional practice of constructing multiple, but relatively shallow (e.g., ~50-75 m) heat exchange wells for residential/commercial heating and cooling applications. There are, however, a number of poorly understood issues having both important practical and scientific implications. Short- and long-term measurements of exchange fluid temperature and heat flux will be made along the entire (600 m) heat exchange path of a deep GSHP system for the first time. Long-term measurements of the heat flux profile will be obtained while the system is in use to meet seasonal heating/cooling demand of a single-family residence. Short-term measurements will obtained from a series of "stimulation" tests designed to investigate perturbations imposed to the system operating variables (e.g., exchange fluid flow rate or input temperature). These data will be used to link the heat flux profile to subsurface heterogeneities in geology and hydrogeology (e.g., groundwater flow), and the natural geothermal gradient. Results will also be used to ground-truth and calibrate a finite-element based numerical model to conduct long-term (e.g., 20-year) simulations of GSHP efficiency, life-cycle assessment, and to extend the project results for application to more general subsurface geologies, borehole geometries, and seasonal heating and cooling applications. Project results will have significant practical and scientific merit. Information from the instrumentation and modeling effort can be used to design better ground loop systems for unconventionally deep (as well as shallow) geothermal heat exchange systems, to quantify short- and long-term GSHP performance, and to assess the implications of seasonal load imbalance on system efficiency. Information can also be used to address basic scientific questions regarding the potential geochemical ramifications of using the earth as a heat source/sink and to more effectively calibrate natural records of climate change gleaned from deep subsurface temperature measurements. While the study is expected to impact the geothermal industry on a broad scale, the impact to the industry in Wisconsin in particular is expected to be significant. Over 93% of Wisconsin's electrical fuel is imported from other states and geothermal energy is increasingly being considered an essential energy source. Project activities will be leveraged across multiple educational environments through outreach and teaching activities designed to impact K-12 students, undergraduate students, graduate students, and practicing professionals. Activities will be integrated with: (1) a Research Experience for Undergraduates (REU) program on Energy Geotechnics currently ongoing at the University of Wisconsin-Madison (UW), (2) extension courses offered to the practicing engineering and science community through the UW Engineering Professional Development (EPD) program, including a short course on Design of Geothermal Systems, (3) a platform session with the Wisconsin Geothermal Association, (4) lectures in large freshmen-level courses at UW, (5) dissemination in journal and conference publications, and (6) a geothermal session and field tour for UW-EPD's Badger Camp(TM), a renowned in-residence summer camp for middle school students interested in the STEM fields.

该项目的目标是安装一套全面的光纤（FO）分布式温度传感（DTS）仪器，以获得目前正在威斯康星州建造的非常规深度（~300米）地热地源热泵（GSHP）系统的温度和热流剖面的短期和长期测量。相较于建造多口但相对较浅（例如~50-75米）的住宅/商业供热和制冷换热井的传统做法，建造一口非常深的换热井具有潜在优势。然而，仍有一些不为人所知的问题具有重要的实际意义和科学意义。将首次沿着深埋地源热泵系统的整个（600米）换热路径进行交换流体温度和热流通量的短期和长期测量。当系统用于满足单户住宅的季节性供暖/制冷需求时，将获得长期的热流密度分布数据。短期测量将从一系列“刺激”测试中获得，这些测试旨在研究施加给系统操作变量的扰动（例如，交换流体流速或输入温度）。这些数据将用于将热通量剖面与地质和水文地质（例如地下水流动）中的地下非均质性以及天然地热梯度联系起来。结果还将用于地面真相和校准基于有限元的数值模型，以进行长期（例如20年）的地源热泵效率模拟，生命周期评估，并将项目结果扩展到更一般的地下地质，井眼几何形状以及季节性加热和冷却应用。项目成果将具有重要的实用价值和科学价值。来自仪器和建模工作的信息可用于为非常规深层（以及浅层）地热交换系统设计更好的接地回路系统，量化短期和长期地源热泵性能，并评估季节性负荷不平衡对系统效率的影响。这些信息还可用于解决有关利用地球作为热源/汇的潜在地球化学后果的基本科学问题，并更有效地校准从深层地下温度测量中收集到的气候变化自然记录。虽然这项研究预计将对地热产业产生广泛的影响，但对威斯康星州的地热产业的影响预计将尤为显著。威斯康辛州93%以上的电力燃料是从其他州进口的，地热能越来越被认为是一种重要的能源。项目活动将通过旨在影响K-12学生、本科生、研究生和实践专业人员的外展和教学活动，在多个教育环境中发挥作用。活动将与：(1)威斯康星大学麦迪逊分校（UW）正在进行的能源岩土工程本科生研究经验项目（REU）；(2)通过威斯康星大学工程专业发展（EPD）项目为实践工程和科学社区提供的扩展课程，包括地热系统设计的短期课程；(3)威斯康星地热协会的平台会议；(4)威斯康星大学新生大型课程讲座；(5)在期刊和会议出版物上进行宣传；(6)参加威斯康星大学环境保护学院獾营（TM）的地热会议和实地考察。獾营是一个著名的针对对STEM领域感兴趣的中学生的夏令营。