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) 提供地下热导率的估计，以设计地面耦合热泵系统。地热行业常用的传统测试方法旨在重现地热交换器 (GHE) 中发生的传热现象，以推断地下特性。开发了重型移动设备来进行测试，其中在 GHE 中流动的水通过泵循环并通过地表的电气元件加热以将热量注入地下。分析瞬态温度响应以推断地下热导率。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，当电位差为 240 V 时，需要 31 至 50 A 的电流强度。这种传统的测试方法是一般认为昂贵。在这个研究项目中，我们提出了一种新的 TRT 方法，该方法可能比传统的 TRT 更便宜，因为它使用低功率运行，可提供地下热导率的垂直剖面，并且可以在任何地方部署。这种新方法使用插入 GHE 单个管道的加热电缆向地下注入热量。 然而，以前使用加热电缆的 TRT 方法已经过修改，使得 GHE 中的加热电缆段链降低，与传统的 TRT 或使用连续加热电缆的 TRT 相比，这可以减少所需的电源。在热注入后的热恢复期间，沿着加热段的深度测量温度，需要比传统TRT更长的监测时间。第一个原型已用于评估新方法。该项目的主要目标是开发和验证一种新的更好的原型，工业界可以使用该原型来验证技术，以便在其完全商业化之前引起人们的兴趣。