Thermal and mechanical aspects of the response of embedded retaining walls used as shallow geothermal heat exchangers

Bourne–Webb, Peter J.; Freitas, Teresa; Gonçalves, R.A. da Costa

doi:10.1016/j.enbuild.2016.04.075

Cited by 75 publications

(51 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, as the heat exchange process proceeds from the initial transient condition towards a steady state condition, the difference in temperature between the air inside the excavation and the soil becomes the predominant factor, to the detriment mainly of the panel width. This is consistent with the long term steady state analysis carried out by Bourne Webb et al (2016) which showed heat transfer to be dominated by the interface with the inside of the excavation. The effect of pipe spacing correspondingly decreases as time progresses, but always remains among the top three parameters.…”

Section: Discussionsupporting

confidence: 78%

“…By the end of the numerical simulation the heat transfer rates drop to <20 W/m 2 . These values are comparable to those presented by Bourne Webb et al (2016) and slightly lower than those suggested by Brandl (2006) as pre design values.…”

Section: Resultssupporting

confidence: 71%

“…In the long term this assumption is more representative of tunnels, and other applications where high airflow persists (Bourne-Webb et al 2016). However, in contrast to Bourne Webb et al (2016), which applied steady state thermal analysis, this study will be transient and consider the changing impact of the different parameters with time. The full list of parameters considered in this study and their range of variability are summarised in Table 4.…”

Section: Choice Of Parametersmentioning

confidence: 99%

“…Bourne Webb et al (2016) investigated the effect of applying the two different types of boundary condition. For the long term they concluded that imposing constant temperature could be non-conservative with respect to heating capacity, although if airflow in the excavation is faster than 3 to 5 m/s (as it might occur for instance in tunnels), this assumption will not be too far in error.…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…Despite the increasing interest for such applications, relative little work has been carried out on the study of diaphragm walls converted to energy geostructures (Bourne-Webb et al 2016;Bourne-Webb et al 2015;ICConsulten 2005;Sterpi et al 2014;. Certainly, there has been no rigorous parametric assessment of the capability of energy diaphragm walls, and few attempts to fully justify design choices and assumptions.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Energy performance of diaphragm walls used as heat exchangers

Donna

Cecinato

Loveridge

et al. 2017

Proceedings of the Institution of Civil Engineers - Geotechnica

View full text Add to dashboard Cite

The possibility of equipping diaphragm walls as ground heat exchangers to meet the full or partial heating and cooling demands of overlying or adjacent buildings has been explored in recent years. In this paper, the factors affecting the energy performance of diaphragm walls equipped as heat exchangers are investigated through finite element modelling. The numerical approach employed is first validated using available experimental data and then applied to perform parametric analyses. Parameters considered in the analysis include panel width, the ratio between the wall and excavation depths, heat transfer pipe spacing, concrete cover, heat-carrier fluid velocity, concrete thermal properties and the temperature difference between the air within the excavation and the soil behind the wall. The results indicate that increasing the number of pipes by reducing their spacing is the primary route to increasing energy efficiency in the short term. However, the thermal properties of the wall concrete and the temperature excess within the excavation space are also important, with the latter becoming the most significant in the medium to long term. This confirms the benefits of exploiting the retaining walls installed for railway tunnels and metro stations where additional sources of heat are available.

show abstract

Section: Discussionsupporting

confidence: 78%

Section: Resultssupporting

confidence: 71%