Innovative thermal response tests technique with a low power source

热响应测试（trt）提供了地下导热系数的估计，以设计地面耦合热泵系统。地热行业常用的常规测试方法旨在重现在地下换热器（GHE）中发生的传热现象，以推断地下性质。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，并用表面的电气元件加热以将热量注入地下。通过分析瞬态温度响应来推断地下热导率。因此，在150米长的GHE中进行这样的TRT所需的总加热功率在7.5到12 kW之间，当电位差为240 V时，需要31到50 a的电流强度。这种传统的测试方法通常被认为是昂贵的。在这个研究项目中，我们提出了一种新的TRT方法，它比传统的TRT方法更便宜，因为它使用低功率源，可以提供地下热导率的垂直剖面，并且可以部署在任何地方。这种新方法将加热电缆插入到GHE的单个管道中，将热量注入地下。然而，对带有加热电缆的前TRT方法进行了修改，使得GHE中的加热电缆部分链降低，与传统的TRT或带有连续加热电缆的TRT相比，这可以减少所需的电源。在热注入后的热回收过程中，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，可以用于工业验证技术，以便在完全商业化之前创造兴趣。

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.