Efficient finite element formulation for geothermal heating systems. Part I: steady state

Al‐Khoury, Rafid; Bonnier, P.G.; Brinkgreve, R.B.J.

doi:10.1002/nme.1313

Cited by 133 publications

(73 citation statements)

References 8 publications

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“…Al-Khoury et al [28][29][30] proposed 3D numerical model depicting thermal interactions among the BHE elements including inletpipe, outlet-pipe and grout. This model addresses the formulation equilibrium, the effect of thermal resistance and the FEM discretization.…”

Section: Fig1 Scheme Diagram Of Ep Elementsmentioning

confidence: 99%

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3D transient heat transfer numerical analysis of multiple energy piles

Cui

Zhu

2017

Energy and Buildings

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This paper presents a three-dimensional (3D) transient heat transfer numerical model for multiple energy piles based on the finite volume method (FVM). The initial and boundary conditions are established and the effects of "thermal short-circulating" between two pipes of a U-tube in energy pile are investigated. Thermal partial differential equations are discretized at the spatial nodal points and solved by linear approximation method. Temperature variations of working fluid, energy pile and its surrounding soil from simulation program are compared with experimental data to validate the developed model. In addition, the influences of fluid flow rate and U-tube shank spacing are analysed. It is established that the shank spacing should be set in a range of 0.06m to 0.10m to reduce heat transfer between the two pipes and meet the structural requirement. Meanwhile, the flow rate should be controlled in a range of 0.5m 3 /h to 0.7m 3 /h to avoid the low outlet fluid temperature and decrease the influence of "thermal short-circuiting".

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Section: Fig1 Scheme Diagram Of Ep Elementsmentioning

confidence: 99%

“…(14) and (15) denote the volumes of the specific components, and the right sides denote the contact surface regions for the interacting surfaces. Based on the simple model presented by Al-Khoury et al [28][29][30], heat transfer coefficients of U-tube can be written as…”

Section: Fig3 Graphical Scheme Of Modelling Fluid In the Pipe Loopmentioning

confidence: 99%

3D transient heat transfer numerical analysis of multiple energy piles

Cui

Zhu

2017

Energy and Buildings

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“…To combat excessive runtimes, theoretical and computational assumptions and approximations have been developed. The work of Al-Khoury et al, (2005) presented a simplification for the analysis of heat flow in BHEs. The model was formulated such that it allows for the utilization of relatively large elements, alleviating thus the need for extremely fine meshes that are typically required in modelling such systems.…”

Section: Modelling Urs and Gshpsmentioning

confidence: 99%

“…Most of the early numerical models were associated with low computational efficiency. In order to overcome this barrier Al-Khoury et al (2005) On the other hand, numerical models aiming to study heat transfers in and around URs have also been developed. A few examples include the work of Hu et al (2008), Ting et al (2009), Mimouni et al (2013) and Barla and Perino (2014).…”

Section: Numerical Ur and Bhe Modelsmentioning

confidence: 99%

Ground source heat pumps and their interactions with underground railway tunnels in an urban environment: A review

Revesz

Chaer

Thompson³

et al. 2016

Applied Thermal Engineering

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Ground source heat pumps (GSHPs) can provide an efficient way of heating and cooling buildings due to their high operating efficiencies. The implementation of these systems in urban environments could have further benefits. In such locations the ground source heat is potentially more accessible through alternative sources such as through underground railways (URs). The heat from the ground surrounding an UR tunnel could be exploited to enhance the operation of GSHPs operating in heating mode. To achieve this, the interactions of GSHPs with neighbouring URs must be fully understood but there is little exploration of these in current literature. This paper focuses on the potential benefit of understanding such interactions. It starts with a summary of typical and alternative heat sources for heat pumps and then it highlights the reasons why URs can be regarded as one of the most attractive ones. Then the paper reviews the current approaches used to model GSHPs and URs. Based on that review the paper suggests a method for the combined analysis of GSHPs and URs. The reasons why London is a sensible choice for a case study are also described. Summary of results from a preliminary investigation are also presented.

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“…Some models come close to this level of detail [8,9,10,11] but stop short of fully discretising the heat transfer fluid. Generally three-dimensional models remain computationally demanding and so are not commonly used for routine design and analysis tasks.…”

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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Efficient finite element formulation for geothermal heating systems. Part I: steady state

Cited by 133 publications

References 8 publications

3D transient heat transfer numerical analysis of multiple energy piles

3D transient heat transfer numerical analysis of multiple energy piles

Ground source heat pumps and their interactions with underground railway tunnels in an urban environment: A review

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

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