Please use this identifier to cite or link to this item: https://www.um.edu.mt/library/oar/handle/123456789/82787
Title: The effect of shank-space on the thermal performance of shallow vertical u-tube ground heat exchangers
Authors: Vella, Christopher
Borg, Simon Paul
Micallef, Daniel
Keywords: Ground source heat pump systems
Computational fluid dynamics
Heat pumps
Geothermal engineering
Issue Date: 2020
Publisher: MDPI
Citation: Vella, C., Borg, S. P., & Micallef, D. (2020). The effect of shank-space on the thermal performance of shallow vertical u-tube ground heat exchangers. Energies 2020, 13(3), 602.
Abstract: One parameter that may affect the performance of a ground source heat pump is the shank-space, the center-to-center distance between the two branches of a vertical U-tube used in a ground heat exchanger. A 3D steady-state computational fluid dynamics (CFD) model of a U-tube ground heat exchanger was used to investigate the influence of varying shank-space on the thermal performance of two isolated vertical shallow U-tubes, one 20 m deep and the other 40 m deep, given that most existing research focuses on systems making use of deeper boreholes. The models adopt an innovative approach, whereby the U-junction at the bottom of the U-tube is eliminated, thus facilitating the computational process. The results obtained show that, although the temperature drop across the U-tube varies for different shank-spaces and is lowest and highest for the closest and the widest shank-spaces, respectively, this temperature drop is not linear with increases in shank-space, and the thermal performance improvement drastically diminishes with increasing shank-space. This indicates that, for shallow U-tubes, the temperature drop is more dependent on the length of the pipework.
URI: https://www.um.edu.mt/library/oar/handle/123456789/82787
Appears in Collections:Scholarly Works - FacBenED



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