A multi-objective design optimization strategy for vertical ground heat exchangers

Huang, Shuai; Li, Zhixiong; Wang, Fenghao

doi:10.1016/j.enbuild.2014.11.024

Cited by 54 publications

(10 citation statements)

References 28 publications

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“…For a given heating and cooling loads, optimization of GSHP system was done by Sanaye and Niroomand [9]. Considering multi-objective optimization design of BHEs, Huang et al [10] proposed an optimization design strategy to minimize the system cost. Hence there is good opportunity to simulate the GHEs numerically for optimization of performance of GSHP systems.…”

Section: Introductionmentioning

confidence: 99%

Numerical Optimization of Double Tube GHE for Ground Source Heat Pump

Ali¹

2017

IJSGE

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Abstract:In this paper, a two-dimensional axisymmetric numerical simulation model was developed for optimization of double (coaxial) tube vertical ground heat exchangers (GHEs) in cooling mode. Details of the heat transfer rates and pressure drops for each model are presented and analyzed. The results of the numerical study of optimization of double tube vertical GHEs have been done by considering heat transfer rates and pressure drops. The effect of different inlet and outlet tube diameters, and mass flow rates were numerically investigated. Effect of the different materials on heat transfer and longtime operation also discussed. The double tube vertical GHEs are more effective in laminar flow condition considering balance between heat transfer and pressure drop. The results indicate that since in laminar flow condition, pressure drop is not significantly high, it is possible to reduce the inlet and outlet diameter of double tube GHEs if double tube GHEs operate in laminar flow condition. The heat transfer rate decreased only 17% but diameter of the inlet tube can be reduced from 130 mm to 40 mm with fixed outlet diameter 20 mm. Heat transfer rate can also be enhanced by reducing the outlet tube diameter for a fixed inlet tube diameter. Long time operation suggested the possibility of installation of multiple double tube GHE at 2.0 m apart.

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Section: Introductionmentioning

confidence: 99%

Numerical Optimization of Double Tube GHE for Ground Source Heat Pump

Ali¹

2017

IJSGE

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“…Given that the issue of variations in shank-space revolves around the phenomenon of thermal resistance and thermal short-circuiting, this is often studied in conjunction with variations in other parameters, such as borehole depth, borehole radius, fluid mass flow rate, U-tube radius, U-tube pipe material, and grout thermal conductivity among others [23]. Recent work done by Zhou et al [24], for example, uses the Taguchi method to find the effect of eight parameters (including most of the above mentioned) on the thermal resistance, concluding that the shank-space has the most substantial impact on the thermal performance of ground heat exchangers.…”

Section: Effect Of Shank-space On System Performancementioning

confidence: 99%

The Effect of Shank-Space on the Thermal Performance of Shallow Vertical U-Tube Ground Heat Exchangers

Vella¹,

Borg²,

Micallef³

2020

Energies

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One parameter that may affect the performance of a ground source heat pump is the shank-space, the center-to-center distance between the two branches of a vertical U-tube used in a ground heat exchanger. A 3D steady-state computational fluid dynamics (CFD) model of a U-tube ground heat exchanger was used to investigate the influence of varying shank-space on the thermal performance of two isolated vertical shallow U-tubes, one 20 m deep and the other 40 m deep, given that most existing research focuses on systems making use of deeper boreholes. The models adopt an innovative approach, whereby the U-junction at the bottom of the U-tube is eliminated, thus facilitating the computational process. The results obtained show that, although the temperature drop across the U-tube varies for different shank-spaces and is lowest and highest for the closest and the widest shank-spaces, respectively, this temperature drop is not linear with increases in shank-space, and the thermal performance improvement drastically diminishes with increasing shank-space. This indicates that, for shallow U-tubes, the temperature drop is more dependent on the length of the pipework.

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“…Sayyaadi et al [11] used the total revenue requirement (TRR) method by using a multi-objective genetic algorithm, MOGA, by defining the thermodynamic and thermoeconomic objective functions. Huang et al [12] also performed design optimization of BHEs for decision making purposes. They performed the mathematical modelling of BHEs and performed MOGA in Matlab to derive entropy generations.…”

Section: Proposed Methodologymentioning

confidence: 99%

Development of a Multi-Objective Sizing Method for Borehole Heat Exchangers during the Early Design Phase

Park

Kim

Jang³

et al. 2017

Sustainability

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Ground-source heat pump (GSHP) systems coupled with borehole heat exchangers (BHEs) are widely used as a renewable energy source. However, the high initial costs to install the BHEs still acts as an obstacle in the expansion of these renewable energy source systems. Specifically, in South Korea, a typical residential type corresponds to an apartment building with a high building-to-land ratio for land efficiency, and thus the space to install the BHEs is usually insufficient. Furthermore, the high initial cost issue of BHEs makes it difficult to ensure the feasibility of GSHP projects in this type of a situation. This study proposes a novel BHE sizing method to support the process of sizing energy sources in the design development phase of a construction project. Life cycle cost (LCC) analysis was combined with a tool to optimize BHE sizing by considering various economic aspects. Entering water temperatures (EWT) to heat pumps in conjunction with the LCC were used to define objective functions. Consequently, Pareto optimal solutions were obtained on the EWT-LCC plot. A group of Pareto optimal solutions forms a Pareto-curve, and each point on the curve indicates a possible sizing scenario or alternative. Finally, it is possible for decision makers to compare the solutions that include both technical and economic information. The Pareto optimal solutions are expected to support proper decision making in the early design phase.

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A multi-objective design optimization strategy for vertical ground heat exchangers

Cited by 54 publications

References 28 publications

Numerical Optimization of Double Tube GHE for Ground Source Heat Pump

Numerical Optimization of Double Tube GHE for Ground Source Heat Pump

The Effect of Shank-Space on the Thermal Performance of Shallow Vertical U-Tube Ground Heat Exchangers

Development of a Multi-Objective Sizing Method for Borehole Heat Exchangers during the Early Design Phase

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