Finite cylinder-source model for energy pile heat exchangers: Effects of thermal storage and vertical temperature variations

Bandos, Tatyana V.; Campos-Celador, Á.; González, Luis Español; Sala-Lizarraga, José M.

doi:10.1016/j.energy.2014.10.053

Cited by 46 publications

(17 citation statements)

References 17 publications

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“…They concluded that the swirl flow effect of the snail caused some increase in pressure drop while this effect was unimportant compared with the improvement in heat transfer capacity. Bandos et al [10] studied the effects of thermal storage and vertical temperature variations on energy pile heat exchangers. Promvonge and Eiamsa-ard [11] order to enhance in heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on turbulent flow and heat transfer in an air to water heat exchanger using perforated circular-ring

Sheikholeslami

Gorji-Bandpy

Ganji

2016

Experimental Thermal and Fluid Science

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Section: Introductionmentioning

confidence: 99%

Experimental study on turbulent flow and heat transfer in an air to water heat exchanger using perforated circular-ring

Sheikholeslami

Gorji-Bandpy

Ganji

2016

Experimental Thermal and Fluid Science

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“…The first category includes analytical solutions such as the line and cylindrical source finite solutions suggested by References [116] and [115], the finite line source solution presented by Reference [155], the composite cylindrical model to account for the contrasting thermal properties of the pile and the soil reported in References [156,157], the infinite solid cylindrical heat source model described in References [91,158], and semi analytical models such as those described in Reference [159]. The second category includes temperature response empirical functions (so-called G-functions), e.g., see Reference [154], which are developed for specific ranges of pile heat exchanger geometries and provide temperature solutions for different pile aspects ratios (shown in Figure 18).…”

Section: Thermal Response Testing Of Foundation Pile Heat Exchangersmentioning

confidence: 99%

Characterisation of Ground Thermal and Thermo-Mechanical Behaviour for Shallow Geothermal Energy Applications

et al. 2017

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Increasing use of the ground as a thermal reservoir is expected in the near future. Shallow geothermal energy (SGE) systems have proved to be sustainable alternative solutions for buildings and infrastructure conditioning in many areas across the globe in the past decades. Recently novel solutions, including energy geostructures, where SGE systems are coupled with foundation heat exchangers, have also been developed. The performance of these systems is dependent on a series of factors, among which the thermal properties of the soil play a major role. The purpose of this paper is to present, in an integrated manner, the main methods and procedures to assess ground thermal properties for SGE systems and to carry out a critical review of the methods. In particular, laboratory testing through either steady-state or transient methods are discussed and a new synthesis comparing results for different techniques is presented. In situ testing including all variations of the thermal response test is presented in detail, including a first comparison between new and traditional approaches. The issue of different scales between laboratory and in situ measurements is then analysed in detail. Finally, the thermo-hydro-mechanical behaviour of soil is introduced and discussed. These coupled processes are important for confirming the structural integrity of energy geostructures, but routine methods for parameter determination are still lacking.

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“…Second, the approach was based on the assumption of the infinite line heat source. The finite line heat source model [12,13] was required to analyze high-resolution stepwise effective thermal conductivities. Finally, the analytic solutions of temperature profiles in a U-tube [30] would aid the analysis especially in the relatively short heating time to obtain more reasonable estimates of thermal resistance of the BHE.…”

Section: Comparison Of Stepwise Thermal Conductivity Under Natural Anmentioning

confidence: 99%

“…The methodology is summarized in texts such as ASHRAE [10] and IEA [11]. The analysis method has been also developed by using analytical solutions of finite line heat source [12,13], inversion techniques [14], Monte-Carlo method [15] and numerical simulations [5][6][7][8]16]. Especially in this study, the standard TRT is limited because the averaged effective thermal conductivity is insensitive to the geologic structure under the ground [16].…”

Section: Introductionmentioning

confidence: 99%

Field Analysis of Stepwise Effective Thermal Conductivity along a Borehole Heat Exchanger under Artificial Conditions of Groundwater Flow

et al. 2017

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Abstract:Heat advection caused by groundwater flow can potentially improve the performance of a borehole heat exchanger. However, the required flow velocity is not achieved under most natural conditions. This study focuses on artificial groundwater flow generated by pumping and investigates the associated effect in a lowland area near the Toyohira River alluvial fan, Sapporo, Japan. Thermal response test results are compared under natural and artificial groundwater flow conditions. A pumping well is constructed one meter from the borehole. Temperature profiles are measured in the U-tube during testing, using a pair of optic fiber distributed temperature sensors. The effective thermal conductivity is calculated from the profiles obtained in each 10-m sub-layer; this thermal conductivity is termed the stepwise thermal conductivity. Additionally, the upward flow velocity in the pumping well is measured to estimate the mean groundwater flow velocity at the borehole. The results show that effective thermal conductivity increases at depths less than 50 m, where the pumping creates mean velocities greater than 0.1 m d −1 in each sub-layer (1.5 md −1 on average). Thus, a borehole length of 50 m is more reasonable at the test site for its efficiency in a ground source heat pump system coupled with the pumping well than that used.

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Finite cylinder-source model for energy pile heat exchangers: Effects of thermal storage and vertical temperature variations

Cited by 46 publications

References 17 publications

Experimental study on turbulent flow and heat transfer in an air to water heat exchanger using perforated circular-ring

Experimental study on turbulent flow and heat transfer in an air to water heat exchanger using perforated circular-ring

Characterisation of Ground Thermal and Thermo-Mechanical Behaviour for Shallow Geothermal Energy Applications

Field Analysis of Stepwise Effective Thermal Conductivity along a Borehole Heat Exchanger under Artificial Conditions of Groundwater Flow

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