Simulation-Based Comparison Between the Thermal Behavior of Coaxial and Double U-Tube Borehole Heat Exchangers

Quaggiotto, Davide; Zarrella, Angelo; Emmi, Giuseppe; Carli, Michele De; Pockelé, Luc; Vercruysse, Jacques; Psyk, Mario; Righini, Davide; Galgaro, Antonio; Mendrinos, Dimitrios; Bernardi, Adriana

doi:10.3390/en12122321

Cited by 28 publications

(23 citation statements)

References 14 publications

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“…To increase the heat transfer performance of the ground heat exchanger, previous studies have been conducted to change its shape or materials [5][6][7][8][9]. Most of the studies [5][6][7][8][9] on the shape of the ground heat exchanger, compared heat transfer performances through numerical simulation or experimentally analyzed the ground effective thermal conductivity through TRT. However, for the GSHP system applied to actual buildings, a steady state is maintained during a short period of time and the system is mostly operated under part-load condition.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…The heat pump COP can be expressed as the ratio of the heating capacity to the required power, and the uncertainties of the heating capacity and the heat pump power are independent. Therefore, the uncertainty of the heat pump COP can be expressed as shown in Equation (8). The measurement error of the heat transfer rate and COP calculated using Equations (6)-(8) was ± 4.0%.…”

Section: Performance Calculation Equationmentioning

confidence: 99%

“…It, however, does not provide quantitative values for newly developed systems, such as the shape of the ground heat exchanger and the introduction of the heat storage tank. To address this problem, various studies [5][6][7][8][9][10][11][12][13][14][15][16][17][18] have been conducted using experimental and numerical methods.…”

Section: Introductionmentioning

confidence: 99%

“…The estimated heat pump COP of GSHP and heat pump COP of the groundwater heat pump system are 3.47 and 3.64. Quaggiotto et al [8] analyzed the heat exchanger rate of double U-tube type and coaxial type through numerical simulation. According to the simulation result, heat transfer rate of coaxial type has a higher 6.3% in heating than that of the double U-tube.…”

Section: Introductionmentioning

confidence: 99%

“…Performance analysis studies are actively conducted according to performance factors [5][6][7][8][9][10][11][12][13][14][15][16]. However, most of the studies [5,6,8,10,11,14] were conducted through numerical analysis. Most experimental studies have been conducted to verify the suitability of sites by real-scale experiments [17,18].…”

Section: Introductionmentioning

confidence: 99%

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A Study on the Effect of Performance Factor on GSHP System through Real-Scale Experiments in Korea

et al. 2020

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A ground source heat pump system is one of the high-efficient technologies for space heating and cooling since it uses stable underground temperature. However, in actual application, many situations cannot be achieved due to the unsuitable design of operation. In particular, the design characteristics of buildings with different building load patterns are not reflected by the conventional design method. Moreover, the design capacity of the heat pump can be reduced by designing less capacity than the peak load through the introduction of the heat storage tank, but there is no related quantitative design method. Therefore, in this study, the effect of the ground source heat pump system design factors such as shape, length of the ground heat exchanger, and the capacity of the heat storage tank on the system performance was analyzed. To quantify the effect of such factors on system performance, an experimental plant was constructed and case studies were conducted for each design factor.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Performance Calculation Equationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Study on the Effect of Performance Factor on GSHP System through Real-Scale Experiments in Korea

et al. 2020

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Thermal performance of water‐based brines as a heat carrier for ground heat exchanger under severely cold environments

Verma

Tarodiya

Thangavel³

et al. 2022

Heat Trans

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The aim of the present study is to investigate the performance of water‐based brine solutions in the ground heat exchanger (GHX) for space heating applications under severely cold climate conditions. The conventional ethylene glycol (EG) and propylene glycol (PG)‐based water solutions have been considered for investigation. For the closed‐loop vertical U‐tube GHX, a mathematically built model is developed for ambient temperature below 0°C. The thermal performance analysis of GHX is carried out for the variation in fluid flow rate and brine solutions for different mixture percentages of water in EG and PG. The percentage of the mixture and fluid flow rate varied from 25% to 60% and 0.2 to 0.6 LPS, respectively. GHX performance parameters, namely convective coefficient, pressure drop, borehole resistance, and GHX effectiveness are determined for both EG and PG brines. Better performance of GHX is noticed with EG brines as compared to PG brines for similar operating conditions. The drop in convective coefficient from 22% to 44% in the case of PG brines as compared to EG brines with the increase in mixture percentage from 25% to 60%, for the same operating conditions. The pressure drops decreased from 15% to 74% for EG mixture as compared to PG mixture at considered flow rate and mixture percentage. The effectiveness and overall borehole resistance were higher for EG as compared to the PG solution.

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Design and optimization of ground‐coupled refrigeration heat exchanger in Dubai: Numerical approach

Kahwaji,

Capuano,

Boudekji

et al. 2024

Heat Trans

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Ground‐coupled heat exchangers (GCHE) have received significant attention over several decades as a result of increasing the world's energy demand and the need for reducing fossil fuels consumption. Prior studies have demonstrated the effectiveness of utilizing GCHE with refrigeration and heating systems. However, optimizing the performance of GCHE coupled with chillers for heat rejection, especially in extreme hot‐humid climates (where cooling towers are not very effective) is lacking in the literature. In this work, a ground borehole fitted with a coaxial‐tubes heat exchanger (BHE) is numerically simulated. Based on a wide range of data collected for the soil of Dubai, its real in situ thermophysical properties are characterized. The soil's upper layer thickness is relatively small and dry that operates in conduction mode, while the lower one is water‐saturated that works in coupled conduction‐advection mode. The study aims at optimizing the parameters advancing heat rejection into ground considering the actual properties of the soil of Dubai. The results indicate that the more feasible high‐density polyethylene pipes can perform as good as the steel ones. Also, a great finding based on the presented novel design is that insulating the inner pipe can increase the temperature duty by 55%. The proposed design of BHE is relatively inexpensive, more feasible and efficient, which is achieved for the first time based on a deep analysis of Dubai climate and soil. This makes the technology ready to be implemented for industrial applications in Dubai and other regions having a similar climate and soil nature.

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Simulation-Based Comparison Between the Thermal Behavior of Coaxial and Double U-Tube Borehole Heat Exchangers

Cited by 28 publications

References 14 publications

A Study on the Effect of Performance Factor on GSHP System through Real-Scale Experiments in Korea

A Study on the Effect of Performance Factor on GSHP System through Real-Scale Experiments in Korea

Thermal performance of water‐based brines as a heat carrier for ground heat exchanger under severely cold environments

Design and optimization of ground‐coupled refrigeration heat exchanger in Dubai: Numerical approach

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