Effective parameters on the performance of ground heat exchangers: A review of latest advances

Liang, Bin; Chen, Meiqian; Orooji, Yasin

doi:10.1016/j.geothermics.2021.102283

Cited by 51 publications

(23 citation statements)

References 259 publications

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“…As a critical heat exchange component, the borehole field plays an important role in the GSHP system operation [11]. The borehole field consists of an array of borehole heat exchangers which need to be appropriately sized to ensure the GSHP performance and minimize the drilling cost [12].…”

Section: Introductionmentioning

confidence: 99%

Experimental evaluation of IDA ICE and COMSOL models for an asymmetric borehole thermal energy storage field in Nordic climate

Xue

Jokisalo

Kosonen

et al. 2022

Applied Thermal Engineering

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Section: Introductionmentioning

confidence: 99%

Experimental evaluation of IDA ICE and COMSOL models for an asymmetric borehole thermal energy storage field in Nordic climate

Xue

Jokisalo

Kosonen

et al. 2022

Applied Thermal Engineering

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“…As a further option, CO 2 in supercritical conditions has been considered to improve the heat transfer characteristics of the BHE, especially at high temperatures and rapid pressure change applications, such as hot dry rock geothermal exploitation. In their review on the latest advances on ground heat exchangers, Liang et al [103] provided a brief excursus on the application of carbon dioxide as working fluid in GHEs, whose better performance compared to water is strictly related to the conditions of inlet temperature and inlet velocity to guarantee the supercritical state of CO 2 . For the inlet pressure, an optimal value of 28 MPa is suggested.…”

Section: Fluid Flowing In the Ghesmentioning

confidence: 99%

“…Nevertheless, conventional heat transfer fluids, such as the abovementioned water and glycols, but also gas options such as CO 2 and air-ground heat exchangers (AGHE) [103], present a low thermal conductivity. This limit is overcome by the use of more recent technologies: Micro Phase Change Materials slurries (MPCMS) and Nanofluids.…”

Section: Fluid Flowing In the Ghesmentioning

confidence: 99%

“…The reviewed literature highlighted a higher heat transfer coefficients in nanofluids compared with the pure carrier medium, due to the higher thermal conductivity of the nanoparticles together with their size and shape, which provides a larger surface area and a better dispersion in the base fluid [103]. However, a key issue has been highlighted regarding the use of nanofluids, i.e., the increase in viscosity at higher nanoparticles concentration ratios.…”

Section: Fluid Flowing In the Ghesmentioning

confidence: 99%

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State of the Art, Perspective and Obstacles of Ground-Source Heat Pump Technology in the European Building Sector: A Review

et al. 2022

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In the European Union, 40% of the overall final energy consumption is attributable to the buildings sector. A reason for such data may be found considering that the great majority of the building stock is more than 40 years old. According to the European Commission, an interesting potential lies in the refurbishment of the building sector, and heat pump technology has been recognized as one of the most cost-effective solutions to tackle the environmental issue of this sector. Regarding heat pump technology, ground-source heat pumps (GSHPs) have been proven to be the most efficient solution on equal boundary conditions. Despite this, in most EU states’ markets, GSHPs hold only a small market share with respect to air-source heat pumps. In this paper, the state of art and possible future developments of GSHP technology have been reviewed together with a focus on the potential of such technology, most of all on the refurbishment of existing buildings, and on the obstacles to its spread. The state of art of borehole heat exchangers has been studied, focusing on the parameters characterizing the outside pipe and the pipe itself, i.e., pipe and grout materials. Moreover, an overview on the last developments involving refrigerants and secondary fluids is given. Finally, the design and control strategies of GSHPs have been reviewed.

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“…In the former, incompressible fluids, such as water or anti-freeze liquid, circulate through the GHEs; while, in the latter, refrigerant flows through the buried tubes, which are mostly made from copper [2]. The performance of GHEs depends on the GHE geometry, GCHP operation, and the soil properties [6]. In line with this, various design optimization studies have been carried out so far that involve singleobjective optimization or multi-objective optimization of various thermodynamic and economic objectives [7].…”

Section: Introductionmentioning

confidence: 99%

Heat transfer optimization in a horizontal helical-shaped ground heat exchanger through response surface methodology

Malacas

Certeza

Alfonso

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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Various combinations of objective functions and design variables have been considered in several optimization studies of ground heat exchangers (GHEs). In this study, the optimum values of the coil pitch and coil diameter of a helical-shaped GHE were determined to maximize its convection heat transfer rate. Central composite design was used to determine the coil pitch and coil diameter dimensions to be used in GHE modeling. Nine models were generated in Fusion360 which were then exported to ANSYS Fluent for CFD simulation. Then, a second-order model of the convective heat transfer rate per unit length as a function of the coil pitch and coil diameter was generated using the response surface methodology. For the design space considered (coil pitch: 600 to 1200 mm; coil diameter: 600 to 1200mm), the highest heat transfer rate was achieved at a coil diameter of 600mm and at a coil pitch of 1200mm. Furthermore, this study showed that if both the coil pitch and coil diameter are considered simultaneously in the optimization of the heat transfer rate of a helical-shaped GHE, then coil pitch would have a directly proportional relationship with the heat transfer rate, while coil diameter would have an inversely proportional relationship.

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Effective parameters on the performance of ground heat exchangers: A review of latest advances

Cited by 51 publications

References 259 publications

Experimental evaluation of IDA ICE and COMSOL models for an asymmetric borehole thermal energy storage field in Nordic climate

Experimental evaluation of IDA ICE and COMSOL models for an asymmetric borehole thermal energy storage field in Nordic climate

State of the Art, Perspective and Obstacles of Ground-Source Heat Pump Technology in the European Building Sector: A Review

Heat transfer optimization in a horizontal helical-shaped ground heat exchanger through response surface methodology

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