The Effect of Shank-Space on the Thermal Performance of Shallow Vertical U-Tube Ground Heat Exchangers

Vella, Christopher; Borg, Simon; Micallef, Daniel

doi:10.3390/en13030602

Cited by 14 publications

(8 citation statements)

References 33 publications

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“…The model of the BHE lower section was simplified by eliminating the U-junction at the bottom of the U-loop. It is well-known that the removal of a U-shaped connector has no considerable effect on the obtained results and that it significantly reduces the computational cost [38]. Various values for the shank spacing were selected, ranging from 65 mm to 105 mm.…”

Section: Methodsmentioning

confidence: 99%

Effects of the Circuit Arrangement on the Thermal Performance of Double U-Tube Ground Heat Exchangers

et al. 2020

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Given that the issue of variations in geometrical parameters of the borehole heat exchanger (BHE) revolves around the phenomenon of thermal resistance, a thorough understanding of these parameters is beneficial in enhancing thermal performance of BHEs. The present study seeks to identify relative changes in the thermal performance of double U-tube BHEs triggered by alterations in circuit arrangements, as well as the shank spacing and the borehole length. The thermal performance of double U-tube BHEs with different configurations is comprehensively analyzed through a 3D transient numerical code developed by means of the finite element method. The sensitivity of each circuit configuration in terms of the thermal performance to variations of the borehole length and shank spacing is investigated. The impact of the thermal interference between flowing legs, namely thermal short-circuiting, on parameters affecting the borehole thermal resistance is addressed. Furthermore, the energy exchange characteristics for different circuit configurations are quantified by introducing the thermal effectiveness coefficient. The results indicate that the borehole length is more influential than shank spacing in increasing the discrepancy between thermal performances of different circuit configurations. It is shown that deviation of the averaged-over-the-depth mean fluid temperature from the arithmetic mean of the inlet and outlet temperatures is more critical for lower shank spacings and higher borehole lengths.

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Section: Methodsmentioning

confidence: 99%

Effects of the Circuit Arrangement on the Thermal Performance of Double U-Tube Ground Heat Exchangers

et al. 2020

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“…Therefore, it is crucial to perform an optimal design of the heat exchange between the fluid and the ground. This topic was analyzed by Vella et al [157], presenting a study for the performance improvement of a ground-source heat pump. They focused on the effect of the distance between the two vertical U-tubes applied in a counter-flow heat exchanger.…”

Section: Buiding Energy Savingmentioning

confidence: 99%

Recent Advances in Technology, Strategy and Application of Sustainable Energy Systems

et al. 2020

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The global COVID-19 pandemic has had strong impacts on national and international freight, construction and tourism industry, supply chains, and has resulted in a rapid decline in the demand for traditional energy sources. In fact, research has outlined that urban areas depend on global supply chains for their day-to-day basic functions, including energy supplies, food and safe access to potable water. The disruption of global supply chains can leave many urban areas in a very vulnerable position, in which their citizens may struggle to obtain their basic supplies, as the COVID-19 crisis has recently shown. Therefore, solutions aiming to enhance local food, water and energy production systems, even in urban environments, have to be pursued. The COVID-19 crisis has also highlighted in the scientific community the problem of people’s exposure to outdoor and indoor pollution, confirmed as a key element for the increase both in the transmission and severity of the contagion, on top of involving health risks on their own. In this context, most nations are going to adopt new preferential policies to stimulate the development of relevant sustainable energy industries, based on the electrification of the systems supplied by renewable energy sources as confirmed by the International Energy Agency (IEA). Thus, while there is ongoing research focusing on a COVID 19 vaccine, there is also a need for researchers to work cooperatively on novel strategies for world economic recovery incorporating renewable energy policy, technology and management. In this framework, the Sustainable Development of Energy, Water and Environment Systems (SDEWES) conference provides a good platform for researchers and other experts to exchange their academic thoughts, promoting the development and improvements on the renewable energy technologies as well as their role in systems and in the transition towards sustainable energy systems. The 14th SDEWES Conference was held in Dubrovnik, Croatia. It brought together around 570 researchers from 55 countries in the field of sustainable development. The present Special Issue of Energies, specifically dedicated to the 14th SDEWES Conference, focuses on four main fields: energy policy for sustainable development, biomass energy application, building energy saving, and power plant and electric systems.

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“…Real measurement results are required for calculations and simulations. A number of studies [25][26][27][28][29][30][31][32][33][34] have been conducted to evaluate the performance of BHE in heat pump systems. All of these studies described the impact of BHE based on the evaluation of COP improvement in these systems.…”

Section: Introductionmentioning

confidence: 99%

Determination of the Selected Wells Operational Power with Borehole Heat Exchangers Operating in Real Conditions, Based on Experimental Tests

Piotrowska-Woroniak

2021

Energies

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On the basis of experimental studies, the operational power of four borehole heat exchangers (BHE) under real conditions was determined. The research was carried out in 2018–2019. The theoretical power of the BHE was verified with its operating power. The amount of thermal energy absorbed from the ground by individual BHEs, the operating temperatures obtained at the inlet and outlet of the exchanger, the annual brine flow rate, and the average operating power of the tested wells in two heating seasons were compared and analyzed. Both in 2018 and 2019, none of the examined exchangers achieved an average unit capacity of a well. The aim of the work is to verify the specific ground thermal efficiency indicators adopted for the design of the lower heat source, determined using the computational method and the TRT test with data obtained on the basis of experimental tests. The differences between the results of the tests of the operating parameters of the analyzed BHEs were shown. The data obtained in real conditions is valuable in the research and development of the BHE system.

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The Effect of Shank-Space on the Thermal Performance of Shallow Vertical U-Tube Ground Heat Exchangers

Cited by 14 publications

References 33 publications

Effects of the Circuit Arrangement on the Thermal Performance of Double U-Tube Ground Heat Exchangers

Effects of the Circuit Arrangement on the Thermal Performance of Double U-Tube Ground Heat Exchangers

Recent Advances in Technology, Strategy and Application of Sustainable Energy Systems

Determination of the Selected Wells Operational Power with Borehole Heat Exchangers Operating in Real Conditions, Based on Experimental Tests

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