A composite cylindrical model and its application in analysis of thermal response and performance for energy pile

Hu, Pingfang; Zhang, Jing; Lei, Fei; Zhu, Na; Wu, Tianhua

doi:10.1016/j.enbuild.2014.07.046

Cited by 68 publications

(35 citation statements)

References 25 publications

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“…1 shows schematic configurations of the studied energy piles in the current work. The steady state thermal resistance formulae for these energy pile configurations are approximated analytically by [9], as follows;…”

Section: Energy Pile Factorsmentioning

confidence: 99%

“…These reports did not include all elements affecting the thermal resistivity of energy pile. The analytical formulae proposed by [9], have shown nine factors that affect the energy pile steady state thermal resistance. These nine factors are; number of tubes, pile diameter, tube diameter, tube thickness, tube location, pile, tube and soil thermal conductivities, and water flow rate.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Uniform Fractional Factorial Design Tables for Energy Piles With Maximum Thermal Conductance

Ahmed¹,

Al‐Khawaja²,

Suleiman³

2017

WIT Transactions on Ecology and the Environment

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Energy Piles are the heat exchangers of Ground Source Heat Pumps (GSHP) that transfer the buildings heat to the lower temperature shallow ground reducing the energy consumption in the cooling of buildings. These piles are designed with main objective of lowest thermal resistance. In this paper, nine factors influencing the thermal resistance of the energy pile are defined and statistically evaluated. These nine factors are; number of tubes, pile diameter, tube diameter, tube thickness, tube location, pile conductivity, tube conductivity, soil conductivity, and water flow rate. The thermal resistance of the energy pile is calculated using the line source analytical model. The significance of these factors is evaluated using fractional factorial uniform design tables. The results show significant decrease in the pile thermal resistivity with the increase of the tube diameter, number of tubes, water flow rate, and tube and pile thermal conductivities. On the other hand, decrease of the tube thickness, and pile diameter slightly decrease the pile thermal resistivity. Furthermore, the tubes located near the piles outer surface show significant decrease in the pile thermal resistivity. Also, the soil thermal conductivity has shown insignificant effects on the pile thermal resistivity.

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Section: Energy Pile Factorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Uniform Fractional Factorial Design Tables for Energy Piles With Maximum Thermal Conductance

Ahmed¹,

Al‐Khawaja²,

Suleiman³

2017

WIT Transactions on Ecology and the Environment

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“…The large pile diameter and the small depth limit the utilization of composite line source model. A composite cylindrical source model was established based on the composite line source model and the cylindrical source model (Hu, et al 2014).…”

Section: Composite Cylindrical Source Modelmentioning

confidence: 99%

“…Thus the error would be large if the conventional model is still used which assumes the heat transfer process in the borehole is a steady one (Hu, et al 2014). Recently, some methods have been developed to study the thermal performance of pile heat exchangers.…”

Section: Introductionmentioning

confidence: 99%

Three Dimensional Numerical Simulation of Double-U Pile Heat Exchangers

Wang¹,

Hu²,

Xing³

et al. 2017

Proceedings of the IGSHPA Technical/Research Conference and Expo 2017

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“…They found that the temperature variation at the pile axis does not depend on the number of U-tubes and flow states under the constant heat rejection condition. Hu et al [22] presented a composite cylindrical model on the basis of the combination of line source and cylindrical models, which can be used to estimate the transient heat transfer and temperature response over a short time period. They found that the distance between the pipe and BHE wall is a significant factor influencing heat transfer within the BHE.…”

Section: Introductionmentioning

confidence: 99%

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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A composite cylindrical model and its application in analysis of thermal response and performance for energy pile

Cited by 68 publications

References 25 publications

Uniform Fractional Factorial Design Tables for Energy Piles With Maximum Thermal Conductance

Uniform Fractional Factorial Design Tables for Energy Piles With Maximum Thermal Conductance

Three Dimensional Numerical Simulation of Double-U Pile Heat Exchangers

3D transient heat transfer numerical analysis of multiple energy piles

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