An experimental, analytical and numerical study on the thermal efficiency of energy piles in unsaturated soils
| Autor: | Jean-Louis Briaud, Ghassan Anis Akrouch, Marcelo Sánchez |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Thermal efficiency
Materials science business.industry 020209 energy Geothermal energy 0211 other engineering and technologies 02 engineering and technology Physics::Classical Physics Geotechnical Engineering and Engineering Geology Finite element method Physics::Geophysics Computer Science Applications Thermal Heat transfer Heat exchanger 0202 electrical engineering electronic engineering information engineering Geotechnical engineering business Saturation (chemistry) Pile 021101 geological & geomatics engineering |
| Zdroj: | Computers and Geotechnics. 71:207-220 |
| ISSN: | 0266-352X |
| Popis: | Energy piles are bi-functional foundation elements used as structural support as well as ground heat exchangers for shallow geothermal energy systems. Because they are relatively short, energy piles may be partially embedded in unsaturated soils. Saturation conditions influence the thermal properties of the ground and therefore the heat exchange rate, which in turn affects the efficiency of energy piles. This paper combines analytical, experimental and numerical investigations to evaluate the heat exchange rate of energy piles partially or fully embedded in unsaturated soils. The proposed analytical solution is based on the cylindrical heat source theory that treats the soil as a semi-infinite, homogeneous, and isotropic medium. The solution from this theory is multiplied by a function developed analytically in this paper and the outcome is the heat exchange rate for energy piles in unsaturated soils. The proposed function depends on soil saturation, soil and pile thermal properties, and pile geometry. The analytical solution was compared against a finite element solution; which was in turn validated against results from laboratory experiments. Very satisfactory agreements between the analytical, numerical and experimental outputs were observed. The proposed method can be used for a quick and simple evaluation of the efficiency of energy piles in unsaturated conditions. The proposed analytical solution can also be a useful tool for the verification of numerical codes developed for the design of energy piles in unsaturated soils. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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