The University of Southampton
University of Southampton Institutional Repository

Influences on the thermal efficiency of energy piles

Influences on the thermal efficiency of energy piles
Influences on the thermal efficiency of energy piles
Energy piles have recently emerged as a viable alternative to borehole heat exchangers, but their energy efficiency has so far seen little research. In this work, a finite element numerical model is developed for the accurate 3D analysis of transient diffusive and convective heat exchange phenomena taking place in geothermal structures. The model is validated by reproducing both the outcome of a thermal response test carried out on a test pile, and the average response of the linear heat source analytical solution. Then, the model is employed to carry out a parametric analysis to identify the key factors in maximising the pile energy efficiency. It is shown that the most influential design parameter is the number of pipes, which can be more conveniently increased, within a reasonable range, compared to increasing the pile dimensions. The influence of changing pile length, concrete conductivity, pile diameter and concrete cover are also discussed in light of their energetic implications. Counter to engineering intuition, the fluid flow rate does not emerge as important in energy efficiency, provided it is sufficient to ensure turbulent flow. The model presented in this paper can be easily adapted to the detailed study of other types of geothermal structures.
energy piles, geothermal, thermal efficiency, thermal response test, numerical modelling, convection–diffusion
0360-5442
1021-1033
Cecinato, F.
39ce6c19-7429-465e-a769-d9b500a496e6
Loveridge, F.A.
fb5b7ad9-d1b8-40d3-894b-bccedf0e8a77
Cecinato, F.
39ce6c19-7429-465e-a769-d9b500a496e6
Loveridge, F.A.
fb5b7ad9-d1b8-40d3-894b-bccedf0e8a77

Cecinato, F. and Loveridge, F.A. (2015) Influences on the thermal efficiency of energy piles. Energy, 82, 1021-1033. (doi:10.1016/j.energy.2015.02.001).

Record type: Article

Abstract

Energy piles have recently emerged as a viable alternative to borehole heat exchangers, but their energy efficiency has so far seen little research. In this work, a finite element numerical model is developed for the accurate 3D analysis of transient diffusive and convective heat exchange phenomena taking place in geothermal structures. The model is validated by reproducing both the outcome of a thermal response test carried out on a test pile, and the average response of the linear heat source analytical solution. Then, the model is employed to carry out a parametric analysis to identify the key factors in maximising the pile energy efficiency. It is shown that the most influential design parameter is the number of pipes, which can be more conveniently increased, within a reasonable range, compared to increasing the pile dimensions. The influence of changing pile length, concrete conductivity, pile diameter and concrete cover are also discussed in light of their energetic implications. Counter to engineering intuition, the fluid flow rate does not emerge as important in energy efficiency, provided it is sufficient to ensure turbulent flow. The model presented in this paper can be easily adapted to the detailed study of other types of geothermal structures.

Text
Cecinato & Loveridge Rotary Pile Efficiency.pdf - Accepted Manuscript
Download (1MB)

More information

Accepted/In Press date: 1 February 2015
Published date: 15 March 2015
Keywords: energy piles, geothermal, thermal efficiency, thermal response test, numerical modelling, convection–diffusion
Organisations: Infrastructure Group

Identifiers

Local EPrints ID: 374079
URI: https://eprints.soton.ac.uk/id/eprint/374079
ISSN: 0360-5442
PURE UUID: 65fa6f85-d35e-4782-8944-068e65a20e81
ORCID for F.A. Loveridge: ORCID iD orcid.org/0000-0002-6688-6305

Catalogue record

Date deposited: 05 Feb 2015 11:46
Last modified: 14 Aug 2019 18:39

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×