Now showing 1 - 4 of 4
  • Publication
    Developing Geothermal Energy Research Capabilities at University College Dublin
    (Geothermal Association of Ireland, 2011) ;
    Ireland has one of the highest energy dependencies in Europe and as such must adapt quickly to increase renewable energy exploitation levels in order to secure its energy future. A mix of renewable energy technology types (wind, solar, biomass, wave, tidal, geothermal) will be required in order to achieve Ireland’s national renewable energy generation targets. Geothermal (or ground source) energy can have a part to play in this mix. Over the last number of years the School of Civil, Structural & Environmental Engineering in University College Dublin has begun to develop shallow geothermal energy research capabilities in several areas of interest. Early studies involved the investigation of water chemistry and settlement issues at several sites on the Cork docklands. It was concluded that the chemical characteristics of the water contained in the aquifer could hinder the development of open loop geothermal systems in the area, and that settlement may be a potential concern in cases where open loop systems are installed due to the presence of highly compressible alluvium deposits. Subsequent work has involved the development, construction & performance validation of a thermal response testing rig for site thermal characterisation, installation of both domestic and commercial sized energy piles for research purposes and investigation of soil, rock and grout thermal properties using both steady-state and non-steady-state laboratory testing techniques. This paper gives a brief overview of the completed and ongoing work in the School of Civil, Structural & Environmental Engineering.
  • Publication
    Numerical and finite element analysis of heat transfer in a closed loop geothermal system
    (Taylor & Francis, 2013-08) ;
    Analysis of the thermal regime created by a geothermal borehole heat exchanger is performed using a closed form radial heat flow equation, a geothermal borehole heat exchanger design tool and a finite element model. Climatic, heat exchanger construction and building load data are entered into the heat exchanger design tool in order to create a theoretical model along with thermal parameters from a number of geological formations. Output data from the design tool model are used in conjunction with the closed form radial heat flow equation to calculate the predicted temperature with respect to time and distance from the heat exchanger for the modelled ground formations. The output data from the design tool is also used to create a number of finite element method models against which the predictions calculated using the closed form radial heat flow equation can be compared. A good correlation between the temperatures predicted by the finite element models and the closed form equation calculations is observed. However when used within its recommended limiting conditions, the closed form equation is shown to slightly underestimate the temperature of the ground when compared to the finite element model predictions. The limiting conditions associated with the closed form equation are discussed in the context of the output from the finite element method models.
  • Publication
    Thermal response testing of compromised borehole heat exchangers
    (Oxford University Press, 2012-03-19) ;
    The results of five thermal response tests (TRTs) are presented. Three of the tests were carried out consecutively on the same borehole to illustrate the importance of allowing artificially imposed thermal gradients to dissipate prior to commencement or re-commencement of a test following testing issues. The two remaining tests carried out on separate boreholes confirm the results obtained by the first(uncompromised) of the initial three tests. The testing regime demonstrates the necessity of careful performance of TRT’s and shows the variation in costs/required borehole length which may occur if testing problems occur on site.
      537Scopus© Citations 3
  • Publication
    A preliminary study of the effect of groundwater flow on the thermal front created by borehole heat exchangers
    This paper presents an analysis performed using a coupled TEMP/W-SEEP/W finite element model to consider both the conducive and convective effects of groundwater flow on the thermal regime created by a ground source energy system. The change in the development of the sub-surface thermal regime created by ground source energy borehole heat exchangers caused by a groundwater flow across a site, relative to a scenario where groundwater flow does not exist is examined. Analysis is performed using finite element formulations of both single borehole and multi borehole systems. The results of this work show that even a modest groundwater flow across a site can lead to a significant change in the development of the sub-surface thermal regime. It also shows that groundwater flow can result in implications for: proposed developments incorporating ground source energy systems; nearby existing ground source energy systems; potential future nearby ground source energy systems and the use of established software packages currently used for the design of ground source energy systems in the industry.
      334Scopus© Citations 8