Modeling and assessment of the efficiency of horizontal and vertical ground heat exchangers

Florides, Georgios A.; Theofanous, E.; Iosif-Stylianou, I.; Tassou, S.A.; Christodoulides, Paul; Zomeni, Z.; Tsiolakis, Efthymios; Kalogirou, Soteris A.; Messaritis, Vassilios; Pouloupatis, Panayiotis; Panayiotou, Gregoris

doi:10.1016/j.energy.2013.05.053

Cited by 50 publications

(11 citation statements)

References 9 publications

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“…Zhang et al [13] mathematically modeled borehole GHE to optimize the design for GHEs which is favorable to lower the initial cost of the system. Li et al [14] developed a new solution to reduce the thermal interference of vertical U-tube GHE and validate their result with experimental data of Florides et al [15] by using ANSYS Fluent. Jalaluddin and Miyara [16] numerically evaluated the thermal performance and pressure drop of the spiral-tube GHE and compared with that of the U-tube GHE.…”

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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“…A correction method developed by Reference [44] uses the thermal parameters of the probe and sample to automatically determine the effective amount of heat entering into the sample material and evaluate the thermal properties of the sample. Examples of applications in soils/rocks can be found in References [62][63][64][65].…”

Section: Transient Plane Source (Tps) Methodsmentioning

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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“…Currently, due to the large amount of carbon dioxide and other greenhouse gases generated in the use of non-renewable energy such as coal, oil and natural gas, the global climate warming and the worsening of ecological environment have been widespread concerns in the world for energy conservation, environmental protection and sustainable use of energy [1][2]. Geothermal is a new, renewable, clean and pollution-free energy which has attracted increasing attention by people [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Influence of different pumping and recharging schemes on regional groundwater drawdown in groundwater heat pump project: A case in Anhui Fuyang People’s Hospital

Yang

Wang

et al. 2021

THERM SCI

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In the process of exploiting geothermal energy by groundwater heat pump (GWHP), the dynamic equilibrium of regional groundwater drawdown is the basis for sustained operation of GWHP. In this paper, taking the GWHP project of Fuyang People's Hospital in Anhui, China as an example, a mathematical model is established and numerical simulation is carried out based on the hydrogeological conceptual model by using Modflow software. In addition, considering the pattern of same direction recharge, the intersect recharge and the ratio of 90% and 100% reinjection respectively, the area change of the drawdown funnel caused by the GWHP project and the recovery of the water level after the system stopped operation are analyzed. The results show that the funnel area of the pumping well under the 90% recharge ratio is greater than that of the 100% recharge, while the operation result of recharge well is opposite in the most adverse situation of the system with a production volume of 1440m3/d and continuous operation for 4 months. Furthermore, with the same reinjection ratio, the funnel area of the same direction recharge mode is larger than that of the intersect recharge mode in both pumping wells and recharge wells, and increases with the decrease of drawdown. Moreover, with the increase of recharge amount, while the water level of recharge well rises, there is a certain supplement and balance to the water quantity of the pumping well.

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Modeling and assessment of the efficiency of horizontal and vertical ground heat exchangers

Cited by 50 publications

References 9 publications

Numerical Optimization of Double Tube GHE for Ground Source Heat Pump

Numerical Optimization of Double Tube GHE for Ground Source Heat Pump

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

Influence of different pumping and recharging schemes on regional groundwater drawdown in groundwater heat pump project: A case in Anhui Fuyang People’s Hospital

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