Long-term performance of BHE (borehole heat exchanger) fields with negligible groundwater movement

Lazzari, Stefano; Priarone, Antonella; Zanchini, Enzo

doi:10.1016/j.energy.2010.08.028

Cited by 93 publications

(39 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If significant groundwater flow exists, convection and an additional heat transport occur. For consideration of this additional heat transport a higher thermal conductivity value could be used [47,48]. This is however a significant oversimplification because the characteristic timescales for conduction and convection are very different.…”

Section: Influence Of Groundwater Flowmentioning

confidence: 99%

Analysis and design methods for energy geostructures

Bourne–Webb

Burlon²,

Javed

et al. 2016

Renewable and Sustainable Energy Reviews

View full text Add to dashboard Cite

Section: Influence Of Groundwater Flowmentioning

confidence: 99%

Analysis and design methods for energy geostructures

Bourne–Webb

Burlon²,

Javed

et al. 2016

Renewable and Sustainable Energy Reviews

View full text Add to dashboard Cite

“…It was shown that for a single BHE field, the temperature change at 50-m depth and at a distance of 0.1 m from the BHE was smaller than 0.1 K, after a 24-year recovery period. The recovery period increases to 70 years for a multi-BHE field, with array spacing of 7.5 m. Lazzari et al [24] investigated the long-term performance of both single-and multi-BHE fields, with a periodic heat load in a conduction-dominated heat transfer system. They concluded that an almost complete heat load compensation is needed in the case of an infinite square BHE field, even when the spacing between the individual BHEs is large (14 m).…”

Section: Introductionmentioning

confidence: 99%

Analysis of Geo-Temperature Restoration Performance under Intermittent Operation of Borehole Heat Exchanger Fields

Mao

Xing

et al. 2015

Sustainability

View full text Add to dashboard Cite

Intermittent operation can improve the coefficient of performance (COP) of a ground source heat pump (GSHP) system. In this paper, an analytical solution to analyze the geo-temperature restoration performance under intermittent operation of borehole heat exchanger (BHE) fields is established. For this purpose, the moving finite line source model is combined with the g-function and the superposition principle. The model takes into account the heat transfer along the borehole, thermal interference between BHEs, and the influence of groundwater flow. The accuracy of the model is validated through comparison with an experiment carried out under intermittent operation. The model makes it possible to analyze the geo-temperature restoration performance and its influencing factors, such as BHE spacing, heat flow rate, operation mode, and groundwater flow. The main conclusions of this work are as follows. The heat transfer along the borehole should be considered when analyzing the geo-temperature restoration performance. When the BHE spacing increases, the soil temperature change decreases and the heat recovery improves. Therefore, adequate borehole separation distance is essential in the case of a multiple BHE system with unbalanced load. The presence of groundwater flow is associated with interference between the BHEs, which should not be ignored. In the case of long-term operation, the groundwater flow is beneficial to the geo-temperature recovery process, even for downstream BHEs. Finally, a greater groundwater flux leads to a better geo-temperature recovery.

show abstract

“…BHE fields cause regional temperature anomalies, and projected to the surface these large scale temperature anomalies are composed of an array of tens to hundreds of concentric or elliptic temperature plumes that evolve around the BHEs. The larger the BHE field is the less effective the natural lateral conductive heat supply is, so that often the temperature within the field successively declines (Signorelli et al, 2004;Lazzari et al, 2010). Seasonal energy use in heating dominated operation is then reflected by periodic temperature variations that have a long-term decreasing trend (Diao et al, 2010).…”

Section: Introductionmentioning

confidence: 97%