Estimation of thermal properties of soil and backfilling material from thermal response tests (TRTs) for exploiting shallow geothermal energy: Sensitivity, identifiability, and uncertainty

2019 ◽  
Vol 132 ◽  
pp. 1263-1270 ◽  
Author(s):  
Min Li ◽  
Liwen Zhang ◽  
Gang Liu
Keyword(s):  
Thermal Properties ◽  
Geothermal Energy ◽  
Thermal Response ◽  
Shallow Geothermal Energy ◽  
Properties Of Soil

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

Energies ◽  
2017 ◽  
Vol 10 (12) ◽  
pp. 2044 ◽  
Author(s):  
Ana Vieira ◽  
Maria Alberdi-Pagola ◽  
Paul Christodoulides ◽  
Saqib Javed ◽  
Fleur Loveridge ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Mechanical Behaviour ◽  
Geothermal Energy ◽  
Structural Integrity ◽  
Thermal Response ◽  
Coupled Processes ◽  
Parameter Determination ◽  
Energy Applications ◽  
Shallow Geothermal Energy

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.

Actively heated fiber optics based thermal response test

2021 ◽  
Author(s):  
Kai Gu ◽  
Bo Zhang ◽  
Bin Shi ◽  
Chun Liu ◽  
Peter Bayer ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Fiber Optics ◽  
Geothermal Energy ◽  
Thermal Response ◽  
Clean Energy ◽  
Accurate Estimation ◽  
Thermal Response Test ◽  
Investigation Method ◽  
Response Test ◽  
Shallow Geothermal Energy

<p>In the pursuit of sustainable development and the mitigation of climate change, shallow geothermal energy has been widely recognized as a type of clean energy with great potential. Accurate estimation of thermal ground properties is needed to optimally apply shallow geothermal energy technologies, which are of growing importance for the heating and cooling sector. A special challenge is posed by the often significant heterogeneity and variability of the geological media at a site.</p><p>As an innovative investigation method, we focus on the actively heated fiber optics-based thermal response test (ATRT) and its application in a borehole in Changzhou, China. A copper mesh heated optical cable (CMHC), which both serves as a heating source and a temperature sensing cable, was applied in the borehole. By inducing the electric current to the cable at a relatively low power of 26 W/m, the in-situ heating process was recorded at high depth resolution. This information serves to infer the thermal conductivity distribution along the borehole. The presented field experience reveals that the temperature rise in the early phase of the test should not be used due to initial heat accumulation caused by the outer jacket of the CMHC. The comparison of these results with those of a conventional thermal response test (TRT) and a distributed thermal response test (DTRT) in the same borehole confirmed that the ATRT result is reliable (with a difference less than 5% and 1%, respectively). Most importantly, this novel method affords much less energy and testing time.</p><p>Additionally, to estimate the uncertainty and limits associated with the method, a 2D axisymmetric numerical model based on COMSOL Multiphysics® has been developed. The results indicate that an accurate calculated thermal conductivity requires heating duration to be in the range of 90~400 min considering test efficiency and cost. Our study promotes ATRT as an advanced geothermal field investigation method and it also extends the applicability of the thermal response test as a downhole tool for measurement of soil hydraulic properties.</p>

Shallow Geothermal Energy Exploitation in the Hillock-Shaped High Flat Terrain of Eastern Songnen Plain – In the Case of Qing’an, Suihua

2015 ◽  
Vol 1092-1093 ◽  
pp. 79-86
Author(s):  
Fu Li Qi ◽  
Yong Li Li ◽  
Meng Cai Zhang ◽  
Hui Jin ◽  
Yu Chun Bai ◽  
...  
Keyword(s):  
Geothermal Energy ◽  
Thermal Response ◽  
Clean Energy ◽  
Physical Parameters ◽  
Performance Parameters ◽  
Songnen Plain ◽  
Exchange Performance ◽  
Shallow Geothermal Energy ◽  
The Government ◽  
Energy Exploitation

Shallow geothermal energy is a new renewable high-quality clean energy that has aroused great interest of man for its renewability, huge stock, cleanness and high availability. Encouraged by the favorable policies of the government, shallow geothermal energy exploitation in geologically suitable areas has become a great priority. In this paper, principal rock-soil physical parameters are derived from field thermal response test set in the context of Qing’an, Suihua City, and subsurface temperature field is modeled to further establish the heat exchange performance parameters with a view to providing reference for the planning and proper deployment of GSHP-based shallow geothermal energy exploitation in this area.

An Assessment Methodology of Shallow Geothermal Energy Projects

2014 ◽  
Vol 7 (1) ◽  
pp. 169-175 ◽  
Author(s):  
You Shuang ◽  
Li Xiangyu ◽  
Gao Yu ◽  
Tang Wendi
Keyword(s):  
Heat Transfer ◽  
Geothermal Energy ◽  
Thermal Response ◽  
Heat Transfer Efficiency ◽  
Heating And Cooling ◽  
Time Operation ◽  
Assessment Approach ◽  
Long Time ◽  
Shallow Geothermal Energy ◽  
Theoretical And Numerical Analysis

Combination of theoretical and numerical analysis, an assessment approach of shallow geothermal energy project is proposed. A case study on Chongqing is carried out to verify the methods. According to the theoretical calculation, the heat transfer power per meter of typical boreholes in Chongqing is 40 W/m for cooling and 50 W/m for heating. The numerical model of 100m borehole heat exchanger (BHE) of ground sourced heat pump (GSHP) system is built, two sets of heating and cooling loads are input to calculate the ground thermal response, the results show that the thermal unbalance ratio equals to 1.5 would ensure the safe and reliable long time operation of GSHP system. By comparing the single and group borehole model, the heat transfer efficiency of BHE is not influenced by adjacent boreholes with 6m drilling spacing, the temperature distribution among boreholes almost uniform after a year running, however, the increase of cumulative temperature of the ground reaches 2.2°C after five years running.

scholarly journals Continental vs. Global Niche-Based Modelling of Freshwater Species’ Distributions: How Big Are the Differences in the Estimated Climate Change Effects?

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 816
Author(s):  
Danijela Markovic ◽  
Jörg Freyhof ◽  
Oskar Kärcher
Keyword(s):  
Climate Change ◽  
Thermal Properties ◽  
Safety Margin ◽  
Thermal Response ◽  
Future Climate Change ◽  
Freshwater Species ◽  
Response Curves ◽  
Preferred Temperature ◽  
Continental Scale ◽  
Management Actions

Thermal response curves that depict the probability of occurrence along a thermal gradient are used to derive various species’ thermal properties and abilities to cope with warming. However, different thermal responses can be expected for different portions of a species range. We focus on differences in thermal response curves (TRCs) and thermal niche requirements for four freshwater fishes (Coregonus sardinella, Pungitius pungitius, Rutilus rutilus, Salvelinus alpinus) native to Europe at (1) the global and (2) European continental scale. European ranges captured only a portion of the global thermal range with major differences in the minimum (Tmin), maximum (Tmax) and average temperature (Tav) of the respective distributions. Further investigations of the model-derived preferred temperature (Tpref), warming tolerance (WT = Tmax − Tpref), safety margin (SM = Tpref − Tav) and the future climatic impact showed substantially differing results. All considered thermal properties either were under- or overestimated at the European level. Our results highlight that, although continental analyses have an impressive spatial extent, they might deliver misleading estimates of species thermal niches and future climate change impacts, if they do not cover the full species ranges. Studies and management actions should therefore favor whole global range distribution data for analyzing species responses to environmental gradients.

scholarly journals Multidisciplinary Approaches for Assessing a High Temperature Borehole Thermal Energy Storage Facility at Linköping, Sweden

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4379
Author(s):  
Max Hesselbrandt ◽  
Mikael Erlström ◽  
Daniel Sopher ◽  
Jose Acuna
Keyword(s):  
Thermal Properties ◽  
High Temperature ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Thermal Response ◽  
Site Investigation ◽  
Thermal Response Test ◽  
Response Test ◽  
Crystalline Bedrock

Assessing the optimal placement and design of a large-scale high temperature energy storage system in crystalline bedrock is a challenging task. This study applies and evaluates various methods and strategies for pre-site investigation for a potential high temperature borehole thermal energy storage (HT-BTES) system at Linköping in Sweden. The storage is required to shift approximately 70 GWh of excess heat generated from a waste incineration plant during the summer to the winter season. Ideally, the site for the HT-BTES system should be able to accommodate up to 1400 wells to 300 m depth. The presence of major fracture zones, high groundwater flow, anisotropic thermal properties, and thick Quaternary overburden are all factors that play an important role in the performance of an HT-BTES system. Inadequate input data to the modeling and design increases the risk of unsatisfactory performance, unwanted thermal impact on the surroundings, and suboptimal placement of the HT-BTES system, especially in a complex crystalline bedrock setting. Hence, it is crucial that the subsurface geological conditions and associated thermal properties are suitably characterized as part of pre-investigation work. In this study, we utilize a range of methods for pre-site investigation in the greater Distorp area, in the vicinity of Linköping. Ground geophysical methods, including magnetic and Very Low-Frequency (VLF) measurements, are collected across the study area together with outcrop observations and lab analysis on rock samples. Borehole investigations are conducted, including Thermal Response Test (TRT) and Distributed Thermal Response Test (DTRT) measurements, as well as geophysical wireline logging. Drone-based photogrammetry is also applied to characterize the fracture distribution and orientation in outcrops. In the case of the Distorp site, these methods have proven to give useful information to optimize the placement of the HT-BTES system and to inform design and modeling work. Furthermore, many of the methods applied in the study have proven to require only a fraction of the resources required to drill a single well, and hence, can be considered relatively efficient.

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