Geometric arrangement and operation mode adjustment in low-enthalpy geothermal borehole fields for heating

Beck, Markus; Bayer, Peter; Paly, Michael de; Hecht-Méndez, Jozsef; Zell, Andreas

doi:10.1016/j.energy.2012.10.060

Cited by 57 publications

(19 citation statements)

References 36 publications

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“…Providing the piles are all the same geometry, this is effectively the same as assuming all individual heat exchangers operate in parallel. While more complicated approaches can be adopted, and it has been shown that maximum energy output can be obtained by adjusting the flow rate and position of each pile individually [32], [33], this complexity is considered beyond the scope of the current paper. Instead we focus on providing the first multiple heat exchanger G-functions specifically for pile heat exchangers and investigating how typical piled foundation arrangements can affect energy efficiency.…”

Section: Heat Exchanger Configurationmentioning

confidence: 99%

G-Functions for multiple interacting pile heat exchangers

Loveridge

Powrie

2014

Energy

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Pile heat exchangers -where heat transfer pipes are cast into the building piled foundations -offer an opportunity to use ground energy systems without the additional construction costs related to the provision of special purpose heat exchangers. However, analysis methods for pile heat exchangers are still under development. In particular there is an absence of available methods and guidance for the amount of thermal interaction that may occur between adjacent pile heat exchangers and the corresponding reduction in available energy that this will cause. This is of particular importance as the locations of foundation piles are controlled by the structural demands of the building and cannot be optimised with respect to the thermal analysis. This paper presents a method for deriving G-functions for use with multiple pile heat exchangers. Example functions illustrate the primary importance of pile spacing in controlling available energy, followed by the number of piles within any given arrangement. Significantly it was found that the internal thermal behaviour of a pile is not influenced appreciably by adjacent piles. (170 words)

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Section: Heat Exchanger Configurationmentioning

confidence: 99%

G-Functions for multiple interacting pile heat exchangers

Loveridge

Powrie

2014

Energy

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“…Several authors [31,47,48] have presented optimizations by minimizing the existing maximal ground temperature differences. But the heat transfer inside the borehole and thermal short-circuiting between the downward leg of the pipe and the upward leg of the pipe [51] is neglected in these methods.…”

Section: Dimensionless Parameters Dimensionless Parametersmentioning

confidence: 99%

“…[52] Beck M et al [47] for cooling only cases. The efficiency of the heat pump of a geothermal installation is mainly influenced by the fluid temperature coming from the BHE field T fo .…”

Section: Dimensionless Parameters Dimensionless Parametersmentioning

confidence: 99%

“…Different buildings are executed with the different dynamic diurnal load models; how the multi-BHEs temperature field variation and the thermal anomalies changes under different dynamic diurnal load models needs to be studied. On the other hand, several authors [31,47,48] have presented optimizations including arrangement and load assignment for multi-BHEs. They achieved this by minimizing the existing maximal ground temperature differences.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, a zoning operation strategy, in which only the relatively central part of the GHE runs during the low load season, was adopted by Yu Mingzhi et al [46] to alleviate the thermal accumulation. Beck et al [47] recommended several measures, including operation mode adjustment and geometric arrangement, to optimize the performance of the multi-BHEs, but the groundwater flow was not taken into account. Considering the groundwater flow, Jozsef Hecht-Méndez [31] presented a combined simulation optimization procedure for a multiple BHEs field, in which the strategic adjustment of energy extraction rates (loads) of the individual BHEs were considered.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evaluation of Thermal Anomalies in Multi-Boreholes Field Considering the Effects of Groundwater Flow

Song

Han

et al. 2016

Sustainability

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Abstract:In this paper, the performance of multiple boreholes (multi-BHEs) field is evaluated by considering the groundwater flow. Optimization strategies are presented to mitigate thermal anomalies in the BHEs field. This study shows that groundwater flow greatly improves the heat transfer but causes thermal anomalies downstream. To overcome this problem, a heat transfer model is established for multi-boreholes based on temperature field superposition and moving finite line source model (MFLS). The MFLS multi-boreholes model considers the axial effect and groundwater flow and produces results in agreement with the field tested data of a 4ˆ4 boreholes field. Using a dynamic annual load pattern, the long-term performance of the 4ˆ4 boreholes field is analyzed. Three dynamic diurnal cooling load models are proposed to evaluate the temperature changes in the underground. The intermittent load model could reduce the local temperature anomalies in downstream tubes. The optimization model for cooling cases for multi-BHEs is elaborated to keep the outlet temperature as low as possible and minimize the extreme temperature anomalies, and by this, ultimately improve the system performance. Furthermore, the temperature variations and thermal anomalies downstream of multi-BHEs are investigated by evaluating the arrangement optimization and load optimization. The results show that the optimization could mitigate thermal anomalies downstream and reduce the rate of temperature imbalance of the BHEs field.

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