Simulation study on the thermal performance of vertical U-tube heat exchangers for ground source heat pump system

Pu, Liang; Qi, Dawei; Li, Kang; Tan, Hongbo; Li, Yanzhong

doi:10.1016/j.applthermaleng.2014.12.068

Cited by 90 publications

(25 citation statements)

References 21 publications

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“…All these parameters are obtained from the laboratory investigations. The physical parameters of four different layers of the soil are the same as shown in Table 2 (Chen et al, 2015;Pu et al, 2015;Li et al, 2006). Fig.…”

Section: Numerical Analysismentioning

confidence: 99%

Laboratory investigations and numerical analysis of thermal performance of the single U-tube VBHE in multiple-layer substrates

Liu

Huang

Yang

et al. 2018

JTST

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In order to study the thermal performance of a single U-tube VBHE in multiple-layer substrates, the similarity principle was used to build an indoor comprehensive miniature bench of single U-tube VBHE innovatively, and effects of inlet water temperature and hydrogeological geology on the thermal performance of VBHE were analyzed. In addition, numerical simulation was used to assist in the research. The results indicate that to build a laboratory-scale GSHP system model test apparatus based on the similarity principle will achieve long-term test of GSHP system with smaller human and material resources and a shorter experimental cycle. It's more efficient and convenient. The simplified use of uniform soil thermal and physical properties can cause great deviation. Heat flux per unit pipe of the VBHE increases linearly with the temperature difference's increasing between the inlet water and initial soil. The water temperature along the tube under thermal conductivity increasing and decreasing conditions does not decrease as linearly as the temperature's decreasing under the uniform thermal conductivity condition.

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Section: Numerical Analysismentioning

confidence: 99%

Laboratory investigations and numerical analysis of thermal performance of the single U-tube VBHE in multiple-layer substrates

Liu

Huang

Yang

et al. 2018

JTST

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“…To study thermal migration of GHE in subsurface, several previous studies have been implemented to investigate ground thermal migration by monitoring ground temperature distribution (Lamarche et al 2010;Zhang et al 2014;Pu et al 2015;Mielke et al 2014). Raymond et al (2011) studied the temperature inside a borehole at different depths during a TRT.…”

Section: Introductionmentioning

confidence: 99%

Comparison of ground temperature response of energy pile and borehole heat exchanger during thermal response tests

et al. 2016

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Thermal migration of ground heat exchanger (GHE) in subsurface is crucially important to the efficiency and sustainability of ground source heat pump systems. In order to investigate heat transfer efficiency of GHE, ground temperature response during system operation should be analyzed. In this paper, two types of GHEs operate under heating operating condition are simulated by thermal response test. A set of parameters including fluid temperature, borehole wall and ground temperature are monitored with duration of 148 h. The analysis of thermal performance shows that the energy pile has specific thermal rates of 147 W/m which is 230% higher than that of borehole heat exchanger with 56 W/m. Furthermore, heat flux per unit area of the contacting area at borehole wall (q, W/m 2 ) is analyzed. The monitored temperature development at the borehole wall for both types of GHEs can be perfectly explained by q. The finding of this study indicates that the parameter is useful in estimating ground thermal accumulation of GHEs. The larger the q is, the higher the possible of ground thermal accumulation and unstable performance of GHEs would be.

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“…Hence, many scholars use analytical tools such as finite element analysis software and finite difference software to solve problems on energy piles. Bezyan et al (2015) built a 3D model to simulate the heat transfer in geothermal pile-foundation heat exchangers with a spiral pipe configuration [22]; Pu et al (2015) developed a new practical numerical model for the energy pile with vertical U-tube heat exchangers [23]. Further, several scholars had conducted research on energy piles using numerical simulation methods [24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Thermal Effect on Structural Interaction between Energy Pile and Its Host Soil

2017

Advances in Materials Science and Engineering

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Energy pile is one of the promising areas in the burgeoning green power technology; it is gradually gaining attention and will have wide applications in the future. Because of its specific structure, the energy pile has the functions of both a structural element and a heat exchanger. However, most researchers have been paying attention to only the heat transfer process and its efficiency. Very few studies have been done on the structural interaction between the energy pile and its host soil. As the behavior of the host soil is complicated and uncertain, thermal stresses appear with inhomogeneous distribution along the pile, and the peak value and distribution of stress will be affected by the thermal and physical properties and thermal conductivities of the structure and the host soil. In view of the above, it is important to determine thermal-mechanical coupled behavior under these conditions. In this study, a comprehensive method using theoretical derivations and numerical simulation was adopted to analyze the structural interaction between the energy pile and its host soil. The results of this study could provide technical guidance for the construction of energy piles.

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Simulation study on the thermal performance of vertical U-tube heat exchangers for ground source heat pump system

Cited by 90 publications

References 21 publications

Laboratory investigations and numerical analysis of thermal performance of the single U-tube VBHE in multiple-layer substrates

Laboratory investigations and numerical analysis of thermal performance of the single U-tube VBHE in multiple-layer substrates

Comparison of ground temperature response of energy pile and borehole heat exchanger during thermal response tests

Thermal Effect on Structural Interaction between Energy Pile and Its Host Soil

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