A semi-analytical method to generate g-functions for geothermal bore fields

Cimmino, Massimo; Bernier, Michel

doi:10.1016/j.ijheatmasstransfer.2013.11.037

Cited by 147 publications

(91 citation statements)

References 17 publications

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“…where , Information on the use of numerical Laplace transforms for the calculation of borehole wall temperatures is given in (Cimmino, et al 2013;Cimmino and Bernier 2014;Cimmino 2015;Cimmino and Bernier 2015). Segment-to-segment response factor increments are given by the finite line source solution (Claesson and Javed 2011;Cimmino and Bernier 2014).…”

Section: Ground Modelmentioning

confidence: 99%

“…Segment-to-segment response factor increments are given by the finite line source solution (Claesson and Javed 2011;Cimmino and Bernier 2014).…”

Section: Ground Modelmentioning

confidence: 99%

“…Since the finite line source solution assumes a uniform heat extraction or injection rate along the boreholes, contrary to the uniform borehole wall temperature used by Eskilson (1987), thermal response factors obtained from the finite line source solution tend to overestimate Eskilson's g-functions. Cimmino et al (2013) and Cimmino and Bernier (2014) proposed a method, based on the finite line source, to consider the variation of the heat extraction rates along the borehole lengths and obtain thermal response factors for uniform borehole wall temperatures. A similar approach was used by Lazzarotto (2016) and Lazzarotto and Björk (2016) for tilted boreholes.…”

Section: Introductionmentioning

confidence: 99%

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Examination of Ambient Temperature Variations Effects on Predicted Fluid Temperatures in Vertical Boreholes

Cimmino¹

2017

Proceedings of the IGSHPA Technical/Research Conference and Expo 2017

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Section: Ground Modelmentioning

confidence: 99%

“…Segment-to-segment response factor increments are given by the finite line source solution (Claesson and Javed 2011;Cimmino and Bernier 2014).…”

Section: Ground Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Examination of Ambient Temperature Variations Effects on Predicted Fluid Temperatures in Vertical Boreholes

Cimmino¹

2017

Proceedings of the IGSHPA Technical/Research Conference and Expo 2017

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“…Although none of these BCs duly represent a real case, g-functions will better represent temperature changes in the borehole field when all boreholes are fed in parallel, as highlighted by Cimmino et al (2013). This FLS vs. g-function issue was tackled by several authors who proposed modelling straight (Cimmino & Bernier, 2014) and inclined (Lazzarotto, 2016;Lazzarotto & Björk, 2016) boreholes as stacks of FLS while imposing a uniform temperature BC. Cimmino (2015) coupled such as stack-FLS mode to a quasi-steady-state borehole heat transfer model, thereby moving the BC outside of the boreholes, allowing to impose the same inlet temperature for all boreholes in the field.…”

Section: Introduction and Literature Reviewmentioning

confidence: 99%

Design of a laboratory borehole storage model

Mazzotti¹,

Jiang²,

Monzó³

et al. 2018

Proceedings of the IGSHPA Research Track 2018

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This paper presents the design process of a 4x4 Laboratory Borehole Storage (LABS) model through analytical and numerical analyses. This LABS is intended to generate reference Thermal Response Functions (TRFs) as well as to be a validation tool for borehole heat transfer models. The objective of this design process is to determine suitable geometrical and physical parameters for the LABS. An analytical scaling analysis is first performed and important scaling constraints are derived. In particular, it is shown that the downscaling process leads to significantly higher values for Neumann and convective boundary conditions whereas the Fourier number is invariant. A numerical model is then used to verify the scaling laws, determine the size of the LABS, as well as to evaluate the influence of top surface convection and borehole radius on generated TRFs. An adequate shape for the LABS is found to be a quarter cylinder of radius and height 1.0 m, weighing around 1.2 tonnes. Natural convection on the top boundary proves to have a significant effect on the generated TRF with deviations of at least 15%. This convection effect is proposed as an explanation for the difference observed between experimental and analytical results in Cimmino and Bernier (2015). A numerical reproduction of their test leads to a relative difference of 1.1% at the last reported time. As small borehole radii are challenging to reproduce in a LABS, the effect of the borehole radius on TRFs is investigated. It is found that Eskilson's radius correction (1987) is not fully satisfactory and a new correction method must be undertaken.

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“…Models can also be classified according to whether they adopt analytical [1,2,3], numerical or hybrid [4,5,6] approaches. The question of dimensionality and to what level of detail the grout, pipe and fluid components are represented is related to both the time and length scales that are considered.…”

Section: Introductionmentioning

confidence: 99%

An extended two-dimensional borehole heat exchanger model for simulation of short and medium timescale thermal response

Rees

2015

Renewable Energy

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Common approaches to the simulation of Borehole Heat Exchangers (BHEs) assume heat transfer in circulating fluid and grout to be in a quasi-steady state and ignore fluctuations in fluid temperature due to transport of the fluid around the U-tube loop. Such effects have been shown to have an impact on peak temperatures and hence operation of heat pumps systems when short time scales are considered. A model has been developed that combines a two-dimensional numerical model and models of the pipe loop components. A novel heat exchanger analogy is employed to calculate the heat exchanger outlet temperatures such that iterative procedures can be avoided and numerical stability is unconditional. These approaches result in a model that is computationally efficient and captures much of the short timescale dynamic effects represented in fully three-dimensional models. This is demonstrated by comparison with experimental data and by comparing two and three-dimensional model behaviour in the frequency domain. Predicted monthly outlet temperatures and heat transfer rates are furthermore shown to be in close agreement with experimental values and in good agreement with existing borehole heat exchanger models. The model is computationally efficient enough to allow use in routine analysis and design tasks.

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A semi-analytical method to generate g-functions for geothermal bore fields

Cited by 147 publications

References 17 publications

Examination of Ambient Temperature Variations Effects on Predicted Fluid Temperatures in Vertical Boreholes

Examination of Ambient Temperature Variations Effects on Predicted Fluid Temperatures in Vertical Boreholes

Design of a laboratory borehole storage model

An extended two-dimensional borehole heat exchanger model for simulation of short and medium timescale thermal response

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