In situ estimation of ground thermal properties

Witte, Henk

doi:10.1016/b978-0-08-100311-4.00004-2

Cited by 16 publications

(13 citation statements)

References 19 publications

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“…The results of thermal conductivity and thermal diffusion measurements were determined by performing a statistical analysis of 150 measurements for each parameter and sample. The laboratory results are coherent with literature data [16,35,36]. The best thermal properties for heat exchange, thermal conductivity and diffusion, are shown by limestone samples; the heat capacity is little variable between samples.…”

Section: Thermal Rock and Groundwater Featuressupporting

confidence: 80%

“…It consists of a thermal stimulation of geothermal heat exchanger able to measure indirectly the thermal properties of the exchanger and of adjacent soils and rocks, as thermal conductivity, thermal diffusivity and heat capacity [15]. The heat injection and extraction method was used [16].Surface water, groundwater and seawater samples were collected in February 2017 and July 2017 involving six sampling points. The location of water sampling points is shown in Figure 2a.…”

Section: Methodsmentioning

confidence: 99%

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The Compatibility of Geothermal Power Plants with Groundwater Dependent Ecosystems: The Case of the Cesine Wetland (Southern Italy)

et al. 2018

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Abstract:The Cesine Wetland, located along the Adriatic coast, was recognized as a Wetland of International Interest and a National Natural Park. Managed by the "World Wide Fund for nature" (WWF), it is considered a groundwater dependent ecosystem which is affected by seawater intrusion. The site was selected to test the environmental compatibility of a low-enthalpy geothermal power plant (closed loop) operating in the aquifer saturated portion with purpose to improving the visitor centre. For this purpose, the long-lasting thermal impact on groundwater was assessed using a multi-methodological approach. The complex aquifer system was carefully studied with geological, hydrogeological and geochemical surveys, including chemical and isotopic laboratory analyses of surface water, groundwater and seawater. The isotopes δ 18 O, δD, δ 11 B, and 3 H were useful to clarify the recharge contribution, the water mixing and the water age. All information was used to improve the conceptualization of the water system, including aquifers and the boundary conditions for a density driven numerical groundwater model. The purpose was to forecast anthropogenic thermal groundwater variations up to 10 years of plant working before the plant realization and to validate the solution after some working years. All results show the environmental compatibility notwithstanding the peculiar ecological environment.

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Section: Thermal Rock and Groundwater Featuressupporting

confidence: 80%

Section: Methodsmentioning

confidence: 99%

The Compatibility of Geothermal Power Plants with Groundwater Dependent Ecosystems: The Case of the Cesine Wetland (Southern Italy)

et al. 2018

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“…Its execution is recommended for installation capacities larger than 30 kW [87]. This section complements earlier reviews on the topic [88][89][90][91], and presents the state of the practices and methodologies adopted in thermal response testing. In the following sections, the basic constructs of thermal response testing are described, introducing undisturbed ground temperature estimations techniques, standard testing procedures, and main analysis methods.…”

Section: In Situ Thermal Testing (Thermal Response Tests)mentioning

confidence: 99%

Characterisation of Ground Thermal and Thermo-Mechanical Behaviour for Shallow Geothermal Energy Applications

et al. 2017

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Increasing use of the ground as a thermal reservoir is expected in the near future. Shallow geothermal energy (SGE) systems have proved to be sustainable alternative solutions for buildings and infrastructure conditioning in many areas across the globe in the past decades. Recently novel solutions, including energy geostructures, where SGE systems are coupled with foundation heat exchangers, have also been developed. The performance of these systems is dependent on a series of factors, among which the thermal properties of the soil play a major role. The purpose of this paper is to present, in an integrated manner, the main methods and procedures to assess ground thermal properties for SGE systems and to carry out a critical review of the methods. In particular, laboratory testing through either steady-state or transient methods are discussed and a new synthesis comparing results for different techniques is presented. In situ testing including all variations of the thermal response test is presented in detail, including a first comparison between new and traditional approaches. The issue of different scales between laboratory and in situ measurements is then analysed in detail. Finally, the thermo-hydro-mechanical behaviour of soil is introduced and discussed. These coupled processes are important for confirming the structural integrity of energy geostructures, but routine methods for parameter determination are still lacking.

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“…An analysis procedure based on the superposition principle of the basic analytical model solution can also be employed when measured data are affected by variable heat rate. On the other hand, modern apparatus, as described for example in Witte et al (2002) and Rolando (2015), allow to maintain the heat transfer constant during the test by employing a feedback control system. The ground thermal properties are assumed to be homogenous even if usually the geological profile along the borehole heat exchanger includes layers with different characteristics.…”

Section: Introductionmentioning

confidence: 99%

Heat Extraction Distributed Thermal Response Test: A Methodological Approach and In-situ Experiment

Rolando¹,

Acuña²,

Fossa³

2017

Proceedings of the IGSHPA Technical/Research Conference and Expo 2017

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The Thermal Response Test (TRT) is a worldwide adopted in-situ thermal behaviour of the borehole can differ from the result obtained by means of a heat injection TRT. This issue is of peculiar interest for water-filled boreholes, where the BHE thermal resistance is related to the water temperature and density gradient in the borehole filling-space. In this operating mode a heat pump is usually employed and the constant heat transfer rate condition required by the models can be difficult to be respected since the efficiency of the cooling-machine is dependent on the inlet carrier-fluid temperature to the evaporator.In this paper a methodology to perform a heat extraction DTRT with constant heat transfer rate to the ground is presented. The approach described has been applied in a real water-filled borehole installed in Stockholm, Sweden. Data analysis results are presented and the outcomes regarding the evaluation of the local borehole thermal resistance are discussed and compared with those from an erlier heat injection test performed in the same borehole.

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In situ estimation of ground thermal properties

Cited by 16 publications

References 19 publications

The Compatibility of Geothermal Power Plants with Groundwater Dependent Ecosystems: The Case of the Cesine Wetland (Southern Italy)

The Compatibility of Geothermal Power Plants with Groundwater Dependent Ecosystems: The Case of the Cesine Wetland (Southern Italy)

Characterisation of Ground Thermal and Thermo-Mechanical Behaviour for Shallow Geothermal Energy Applications

Heat Extraction Distributed Thermal Response Test: A Methodological Approach and In-situ Experiment

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