A preliminary study of the effect of groundwater flow on the thermal front created by borehole heat exchangers

An analysis of the effects that groundwater flow has on the thermal regime created by a ground source energy system is presented. The change in the development of the sub-surface thermal regime caused by a groundwater flow across a site, relative to a scenario where groundwater flow does not exist, is examined. Analysis is performed using bespoke finite-element formulations of both single- 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

Incorporating Smart Sensing Technologies into the Poultry Industry

Increases in production input costs are driving innovation in the poultry industry in Ireland and worldwide. Integration of so called ‘Precision Livestock Farming’ techniques into the poultry industry supply chain will help producers to optimize management systems. This manuscript provides an overview of monitoring and performance sensor technologies within poultry production. It outlines traditional sensing methods and looks at the potential of novel performance related systems that could be incorporated into production facilities. Critical environmental parameters which are relevant to poultry production include inter alia air temperature, relative humidity, light, air speed and air quality (in particular CO 2 and NH 3 concentrations). Current industry practice with regard to the measurement of these parameters in addition of the effect of these parameters on bird welfare is reviewed, and improvements underpinned by novel technologies and processes are also investigated. Finally, the integration of such systems is also discussed

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

Numerical and finite element analysis of heat transfer in a closed loop geothermal system

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.Irish Research Council for Science, Engineering and TechnologyAuthor has checked copyrightCheck for published version - once published update Embargo date for 1 year from date of publication - OR 27/02/2013kpw26/3/1

Geothermal energy in small countries - laying the foundations for innovative development

Fourth World Engineers Convention: Engineers Power the World – Facing the Global Energy Challenge, Geneva, Switzerland, 4-9 September 2011Creation of an environment in which shallow geothermal energy can thrive will require a coherent approach and a high level of collaboration with professionals from countries that have developed technical expertise in the area. Implementation of regulations, standards and guidelines adapted from best practice in countries such as Switzerland, Germany and Sweden, in addition to understanding the mistakes and successes made by these countries, with respect to the development of their geothermal industries, will help small countries such as Ireland to develop a well-regulated market for the technology. This paper outlines and addresses some of the technical, regulatory and certification issues faced particularly by small countries in their efforts to develop a shallow geothermal energy industry, provides examples of best practice with regard to development in countries with established geothermal energy industries and presents proposed solutions to these issues / barriers using the existing situation in Ireland by way of example.Irish Research Council for Science, Engineering and Technolog

Energy Foundations - Potential for Ireland

Geo-Frontiers 2011, Dallas, Texas, March 13-16, 2011With one of the highest energy dependencies in the European Union, Ireland must adapt quickly to renewable energy technologies or risk paying the penalty in the form of high energy prices in years to come. Escalating energy costs have led to a renewed interest in alternative energy technologies and ground source energy is one such resource which is being increasingly considered. This paper presents some of the practical considerations of energy foundations, evidenced from the installation of a number of test energy piles. In addition, a preliminary feasibility study of an energy foundation system for a planned university administrative building and an overview of the current status of ground source energy technology in Ireland are presented. Building heating and cooling loads are estimated based on high building energy standards which the university hopes to implement in all building projects going forward. The proposed energy foundation system is shown to have the capacity to provide the heating and cooling base loads for the buildingIrish Research Council for Science, Engineering and Technolog

Interpretation of In Situ and Laboratory Thermal Measurements Resulting in Accurate Thermogeological Characterisation

Geotechnical and Geophysical Site Characterization 4, September, 2012Growing worldwide interest in the exploitation of geothermal energy resources has led to a scenario where the technology routinely forms part of building-scale renewable energy feasibility studies. A thorough understanding of site-specific thermogeological parameters is a vital design requirement of such systems and accurate measurement and interpretation of these parameters is necessary in order to inform scientifically rigorous system design. An overview of the theory underlying a number of laboratory and in situ thermal characterization testing methods and the results from a number of testing regimes carried out using the various thermal characterization equipment constructed in University College Dublin are presented. Results from both the laboratory steady-state and non-steady-state thermal analysis systems and the in situ thermal characterization system are shown to provide accurate measurements of soil and rock thermal parameters. In addition, the settlement profiles of a number of the tested materials were investigated in order to gain an in-sight into this potential drawback of exchanging the backfill material placed around electricity cables to optimize thermal transfer efficiency.DG 30/10/12Names JG 2012-11-2

Thermal response testing of compromised borehole heat exchangers

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.Irish Research Council for Science, Engineering and TechnologyCHECK FOR PUBLISHED VERSION WHEN UN-EMBARGOING 12 month embargo from 1 Feb 2012 -- J

Geothermal energy : settlement and water chemistry in Cork, Ireland

Detailed analysis of potential water chemistry and settlement issues associated with the installation of open-loop geothermal systems is infrequently carried out. This has led to the failure of several previously installed systems. Chemical analysis of water extracted from beneath the Cork docklands, Ireland has been performed by the authors in order to assess the suitability of the area for the exploitation of open-loop geothermal energy. The possibility of settlement induced by pumping of groundwater for open-loop systems has also been examined. Current market penetration of ground source heat pumps in Ireland is discussed to illustrate the infancy of the technology in Ireland relative to other European countries and to highlight the necessity of approaching the possible installation of such systems with the care required. Water extracted from beneath the docklands shows that significant water chemistry issues exist. Laboratory and field tests confirm that optimal concentration levels of several water chemistry characteristics are significantly exceeded; leading to the conclusion that open-loop exploitation in the area may not be suitable. In addition, settlement induced by pumping of water could potentially lead to a consolidation settlement in excess of 30 mm due primarily to the existence of highly compressible alluvium.Irish Research Council for Science, Engineering and Technolog

Energy piles: site investigation and analysis

Despite an increasing worldwide use of geothermal energy foundations, there is a lack of published guidelines and results from thermal response testing of such installations. In this paper the results are presented from thermal response, thermal recovery and laboratory thermal testing performed at two sites in Ireland. Some practical issues concerned with the use of thermal response testing rigs, designed for use with deep boreholes, on relatively short piles are discussed and addressed. Given the relatively short geothermally active depth of the energy foundations tested, and the fact that the University College Dublin thermal response testing rig has been designed primarily for testing on medium and deep geothermal boreholes, thermal response tests of shorter durations than are normally used for deep boreholes were performed. The techniques used to analyse the various test results are outlined, and the resulting values of thermal conductivity obtained are within the range of those expected for the prevailing geology of the sites.Irish Research Council for Science, Engineering and TechnologyDeposited by bulk impor