Innovative thermal response tests technique with a low power source

创新的低功率热响应测试技术

• 批准号: 463143-2014
• 负责人: Lamarche, Louis
• 金额: $ 7.85万
• 依托单位: École de technologie supérieure
• 依托单位国家: 加拿大
• 项目类别: Idea to Innovation
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=558269
• 关键词: Innovative; thermal; response; tests; technique

Thermal response tests (TRTs) provide an estimate of the subsurface thermal conductivity to design ground-coupled heat pump systems. The conventional testing method commonly used by the geothermal industry aim to reproduce heat transfer phenomena taking place at a ground heat exchanger (GHE) to infer the subsurface properties. Heavy mobile apparatus were developed to conduct the tests, in which water flowing in the GHE is circulated with a pump and heated with an electric element at surface to inject heat undergroun. The transient temperature response is analyzed to infer the subsurface thermal conductivity. The total heating power needed to conduct such a TRT in a GHE that is 150 m long is therefore between 7.5 to 12 kW, which requires a current intensity of 31 to 50 A when the electric potential difference is 240 V. This conventional testing method is generally considered expensive. In this research project we propose a new TRT method that is potentially cheaper than the conventional TRT because it operates with a low power source, that provides a vertical profile of the subsurface thermal conductivity and that can be deployed everywhere. This new method uses heating cables inserted into a single pipe of the GHE to inject heat in the subsurface. The former TRT method with heating cables has however been modified such that a chain of heating cable sections is lowered in the GHE, which allows a reduction of the required electric power source when compared to conventional TRT or TRT with continuous heating cables. The temperature is measured at depth along heating sections during the thermal recovery following the heat injection, requiring a monitoring time longer than that of the conventional TRTs. A fisrt prototype has been used to evaluate the new method. The main objective of the project is to develop and verify a new better prototype that can be used by industrials to validate the technology in order to create interest before it is fully commercialized.

热响应测试（TRT）提供了一个估计的地下导热系数，设计土壤耦合热泵系统。地热行业常用的常规测试方法旨在再现在地热交换器（GHE）处发生的传热现象以推断地下性质。开发了重型移动的装置来进行测试，其中在GHE中流动的水用泵循环，并在地面用电气元件加热以将热注入地下。瞬态温度响应进行了分析，以推断地下导热系数。因此，在150 m长的GHE中进行这种TRT所需的总加热功率在7.5至12 kW之间，当电势差为240 V时，这需要31至50 A的电流强度。通常认为这种传统的测试方法是昂贵的。在这个研究项目中，我们提出了一种新的TRT方法，它可能比传统的TRT更便宜，因为它使用低功率源，提供了地下热导率的垂直分布，可以部署在任何地方。这种新方法使用加热电缆插入GHE的单个管道中，将热量注入地下。 然而，使用加热电缆的先前TRT方法已经被修改，使得加热电缆段的链在GHE中降低，这允许与传统TRT或使用连续加热电缆的TRT相比减少所需的电源。在注热后的热采过程中，沿沿着加热段在深度处测量温度，需要比传统TRT更长的监测时间。第一个原型已被用来评估新的方法。该项目的主要目标是开发和验证一个新的更好的原型，可供工业界使用，以验证该技术，以便在完全商业化之前引起人们的兴趣。