Academic Journal
Numerical simulation of a freeze–thaw testing procedure for borehole heat exchanger grouts
| العنوان: | Numerical simulation of a freeze–thaw testing procedure for borehole heat exchanger grouts |
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| المؤلفون: | Anbergen, Hauke, Rühaak, Wolfram, Frank, Jens, Sass, Ingo |
| المصدر: | Canadian Geotechnical Journal ; volume 52, issue 8, page 1087-1100 ; ISSN 0008-3674 1208-6010 |
| بيانات النشر: | Canadian Science Publishing |
| سنة النشر: | 2015 |
| الوصف: | The amount of research conducted on geothermal energy as a source for heating and cooling demands of buildings, as well as for electrical energy production, has increased substantially in the past decades. The simulation of freezing and thawing is important for geothermal applications involving ground coupled heat pumps. One area of research is the development of grout cements for borehole heat exchangers (BHE). In many cases, BHEs are operated at temperatures below 0° C due to manifold reasons. Hence, the simulation of freezing and thawing cycles (FTC) is important for such geothermal applications, especially in cold regions. Recently, a testing device for measuring and quantifying the influence of FTC stresses on the mechanical integrity and hydraulic properties of BHE grouts was developed (Anbergen, published in 2014). The testing procedure simulates the downhole in situ conditions as confining radial earth pressure, freezing, and thawing directions from the inside to the outside and under saturated conditions. The hydraulic conductivity can be measured in axial flow direction. Thus, statements regarding the susceptibility of grouts against cyclic freezing and thawing stresses can be made. These results differ substantially from earlier findings, as in situ boundary conditions were not simulated sufficiently. For the verification of the procedure’s thermal process, temperature logs were recorded using thermocouples and thermography imaging. The thermal process was simulated using the finite element method (FEM) groundwater, heat, and mass modeling software FEFLOW. FEFLOW is a common software solution for thermohydraulic coupled groundwater applications with mass transport, as well as geothermal applications. However, up until now, the program could not yet simulate phase changes between solid and liquid phases. To enable the program for such simulations, a plug-in was developed. To do this, a C++ code was written and coupled to the simulation routine of the FEM software. The code is based on a modification of ... |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| DOI: | 10.1139/cgj-2014-0177 |
| الاتاحة: | http://dx.doi.org/10.1139/cgj-2014-0177 http://www.nrcresearchpress.com/doi/full-xml/10.1139/cgj-2014-0177 http://www.nrcresearchpress.com/doi/pdf/10.1139/cgj-2014-0177 |
| Rights: | http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
| رقم الانضمام: | edsbas.6641E60F |
| قاعدة البيانات: | BASE |
| DOI: | 10.1139/cgj-2014-0177 |
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