Borehole modelling: a comparison between a steady-state model and a novel dynamic model in a real ON/OFF GSHP operation

Роса, Маттиа Де; Ruiz-Calvo, Félix; Corberán, José M.; Montagud, C.; Tagliafico, Luca A.

doi:10.1088/1742-6596/547/1/012008

Cited by 14 publications

(15 citation statements)

References 8 publications

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“…However, this type only reproduces the steady-state response of the water temperatures of the GSHE, which produces significant differences on the shape of the temperature curves [34,35]. Therefore, it becomes necessary to use a dynamic model precise enough to model the instantaneous, short-term, and long-term responses of the GSHE, without excessively increasing the computational cost of the whole model.…”

Section: Gshe and External Circuitmentioning

confidence: 99%

“…It was found that the DST was not able to predict the temperature delay in the outlet of the U-tube that occurs due to the water advection, while the B2G was able to reproduce it. Regarding the typical operation of the GSHP system, the DST does not reproduce correctly the response of the fluid inside the BHE, because it is based on a steady-state approach [35]. In the global model presented in this work, the B2G model will be coupled to the g-function model [8], which will be used only for the calculation of the long-term response of the GSHE.…”

Section: Gshe and External Circuitmentioning

confidence: 99%

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Development and Experimental Validation of a TRNSYS Dynamic Tool for Design and Energy Optimization of Ground Source Heat Pump Systems

et al. 2017

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Ground source heat pump (GSHP) systems stand for an efficient technology for renewable heating and cooling in buildings. To optimize not only the design but also the operation of the system, a complete dynamic model becomes a highly useful tool, since it allows testing any design modifications and different optimization strategies without actually implementing them at the experimental facility. Usually, this type of systems presents strong dynamic operating conditions. Therefore, the model should be able to predict not only the steady-state behavior of the system but also the short-term response. This paper presents a complete GSHP system model based on an experimental facility, located at Universitat Politècnica de València. The installation was constructed in the framework of a European collaborative project with title GeoCool. The model, developed in TRNSYS, has been validated against experimental data, and it accurately predicts both the short-and long-term behavior of the system.

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Section: Gshe and External Circuitmentioning

confidence: 99%

Section: Gshe and External Circuitmentioning

confidence: 99%

Development and Experimental Validation of a TRNSYS Dynamic Tool for Design and Energy Optimization of Ground Source Heat Pump Systems

et al. 2017

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“…Numerical computations can instead relax many assumptions that are generally needed to solve analytical models [21,22]. The geometry in particular can be more complex, accounting for finite lengths, thermal interaction of the heat exchangers, multilayer soil [23] and inclusion of the ground water flow [24,25].…”

Section: Introductionmentioning

confidence: 99%

Energy Pile Field Simulation in Large Buildings: Validation of Surface Boundary Assumptions

2019

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As the energy efficiency demands for future buildings become increasingly stringent, preliminary assessments of energy consumption are mandatory. These are possible only through numerical simulations, whose reliability crucially depends on boundary conditions. We therefore investigate their role in numerical estimates for the usage of geothermal energy, performing annual simulations of transient heat transfer for a building employing a geothermal heat pump plant and energy piles. Starting from actual measurements, we solve the heat equations in 2D and 3D using COMSOL Multiphysics and IDA-ICE, discovering a negligible impact of the multiregional ground surface boundary conditions. Moreover, we verify that the thermal mass of the soil medium induces a small vertical temperature gradient on the piles surface. We also find a roughly constant temperature on each horizontal cross-section, with nearly identical average values when either integrated over the full plane or evaluated at one single point. Calculating the yearly heating need for an entire building, we then show that the chosen upper boundary condition affects the energy balance dramatically. Using directly the pipes’ outlet temperature induces a 54% overestimation of the heat flux, while the exact ground surface temperature above the piles reduces the error to 0.03%.

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“…These could be extended in several ways though [12,15,16], from analytical g-functions [17] to superposition of thermal response functions (the so-called Hellström approach) [18,19]. Unfortunately, unavoidable approximations (such as constant wall temperatures) still limit the predictive power of these models [10,12].Numerical computations can instead relax many assumptions that are generally needed to solve analytical models [20,21]. The geometry in particular can be more complex, accounting for finite lengths, thermal interaction of the heat exchangers, multilayer soil [22] and inclusion of the ground water flow [23,24].…”

mentioning

confidence: 99%

“…Numerical computations can instead relax many assumptions that are generally needed to solve analytical models [20,21]. The geometry in particular can be more complex, accounting for finite lengths, thermal interaction of the heat exchangers, multilayer soil [22] and inclusion of the ground water flow [23,24].…”

mentioning

confidence: 99%

Energy Pile Field Simulation in Large Buildings: Validation of Surface Boundary Assumptions

Ferrantelli

Fadejev

Kurnitski

2019

Preprint

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As the energy efficiency demands for future buildings become increasingly stringent, preliminary assessments of energy consumption are mandatory. These are possible only through numerical simulations, whose reliability crucially depends on boundary conditions. We therefore investigate their role in numerical estimates for the usage of geothermal energy, performing annual simulations of transient heat transfer for a building employing a geothermal heat pump plant and energy piles. Starting from actual measurements, we solve the heat equations in 2D and 3D using COMSOL Multiphysics and IDA-ICE, and discover a negligible impact of the multiregional ground surface boundary conditions. Moreover, we verify that the thermal mass of the soil medium induces a small vertical temperature gradient on the piles surface. We also find a roughly constant temperature on each horizontal cross-section, with nearly identical values if the average temperature is integrated over the full plane or evaluated at one single point. Calculating the yearly heating need for an entire building we then show that the chosen upper boundary condition affects the energy balance dramatically. Using directly the pipes’ outlet temperature induces a 54% overestimation of the heat flux, while the exact ground surface temperature above the piles reduces the error to 0.03%.

show abstract

Borehole modelling: a comparison between a steady-state model and a novel dynamic model in a real ON/OFF GSHP operation

Cited by 14 publications

References 8 publications

Development and Experimental Validation of a TRNSYS Dynamic Tool for Design and Energy Optimization of Ground Source Heat Pump Systems

Development and Experimental Validation of a TRNSYS Dynamic Tool for Design and Energy Optimization of Ground Source Heat Pump Systems

Energy Pile Field Simulation in Large Buildings: Validation of Surface Boundary Assumptions

Energy Pile Field Simulation in Large Buildings: Validation of Surface Boundary Assumptions

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