Numerical analysis of enhanced conductive deep borehole heat exchangers

Renaud, T., Pan, L., Doran, H. , Falcone, G. and Verdin, P. G. (2021) Numerical analysis of enhanced conductive deep borehole heat exchangers. Sustainability, 13(12), 6918. (doi: 10.3390/su13126918)

Abstract

Geothermal energy is a reliable and mature energy source, but it represents less than 1% of the total renewable energy mix. While the enhanced geothermal system (EGS) concept faces technical validation challenges and suffers from public acceptance issues, the development of unconventional deep-well designs can help to improve their efficiency and reliability. Modelling single-EGS-well designs is key to assessing their long-term thermal performances, particularly in unconventional geological settings. Numerical results obtained with the T2WELL/EOS1 code have been validated with available experimental data from a deep borehole heat exchanger (DBHE), where a temperature of 358 ∘C has been measured at a depth of 1962 m. Based on a calibrated model, the thermal performances of two enhanced thermal conductive DBHEs with graphite were compared for high geothermal gradients. The analysis highlights the potential recovery of a variable fraction of vapour. Graphite used along the well appears to be the most suitable solution to enhance the thermal output by 5 to 8% when compared to conventional wells. The theoretical implementation of such well in the Newberry volcano field was investigated with a single and doublet DBHE. The findings provide a robust methodology to assess alternative engineering solutions to current geothermal practices.

• Item Type: Articles
• Additional Information: This research is supported by the UK Engineering and Physical Sciences Research Council (EPSRC) [Grant number EP/N509450/1, Project reference 1878602].
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Falcone, Professor Gioia and Doran, Hannah

Creator Roles

Doran, H.: Software, Writing – review and editing
Falcone, G.: Writing – review and editing, Supervision

• Authors: Renaud, T., Pan, L., Doran, H., Falcone, G., and Verdin, P. G.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: Sustainability
• Publisher: MDPI
• ISSN: 2071-1050
• ISSN (Online): 2071-1050
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Sustainability 13(12):6918
• Publisher Policy: Reproduced under a Creative Commons licence
• Data DOI: 10.17862/cranfield.rd.13624139