A Comparative Study of the Long-Term Performance of Vertical U-Tube Borehole Heat Exchanger and Foundation Piles in a Cold Climate

Philip Adebayo, Charaka Beragama Jathunge, Roman Shor, Abdulmajeed Mohamad, Aggrey Mwesigye

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Citation (Scopus)

Abstract

Ground source heat pumps (GSHP) are gaining traction as a reliable and environmentally friendly solution for space heating and cooling. In cold climates, like Canada, heating loads are greater than cooling loads, which makes the amount of heat extracted from the ground each year greater than heat injected back. This causes a soil temperature decline, gradual performance reduction and possibly eventual failure. The associated ground thermal imbalance and high initial cost of a GSHP are a major challenge to wider adoption of this clean energy technology. This study aims to evaluate and compare the long-term thermal performance of the foundation pile and the conventional borehole heat exchanger of a ground source heat pump system for space heating and cooling in a residential building in Calgary, Canada. A meticulously validated and verified computational fluid dynamics model was developed using Ansys Fluent. The validated model was extended and coupled with transient building energy loads obtained from OpenStudio/EnergyPlus through a developed user defined function. The foundation pile, 20 m deep, 0.139 m diameter with enhanced bentonite grout as backfill material and vertical borehole heat exchanger, 150 m deep, 150 mm diameter were examined for a period of 5 years. The results show that the borehole heat exchanger handling 1.5 tons of the total building load gives better performance with the highest average cooling COP of 3.37 at the end of the 5th year with minimal impact on the ground temperature.

Original languageEnglish
Title of host publicationEnergy
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791887646
DOIs
Publication statusPublished - 2023
Externally publishedYes
EventASME 2023 International Mechanical Engineering Congress and Exposition, IMECE 2023 - New Orleans, United States
Duration: 29 Oct 20232 Nov 2023

Publication series

NameASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)
Volume7

Conference

ConferenceASME 2023 International Mechanical Engineering Congress and Exposition, IMECE 2023
Country/TerritoryUnited States
CityNew Orleans
Period29/10/232/11/23

Keywords

  • Coefficient of Performance
  • Foundation Pile
  • Ground Heat Exchanger
  • Ground Source Heat Pump
  • Numerical Simulation
  • Thermal Performance

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