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Hemmingway, Phil
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Hemmingway, Phil
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Hemmingway, Phil
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Now showing 1 - 10 of 14
- PublicationNumerical and finite element analysis of heat transfer in a closed loop geothermal systemAnalysis 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.
1103 - PublicationGeothermal energy in small countries - laying the foundations for innovative development(World Federation of Engineering Organizations, 2011-09-04)
; Creation 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.779 - PublicationDeveloping Geothermal Energy Research Capabilities at University College DublinIreland 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.
3414 - PublicationInterpretation of In Situ and Laboratory Thermal Measurements Resulting in Accurate Thermogeological CharacterisationGrowing 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.
555 - PublicationMonitoring environmental parameters in poultry production facilities(Institute for Process and Particle Engineering, Graz University of Technology, Austria, 2013-04)
; ; ; Increases in fuel and feed prices are placing a significant burden on the poultry industry in Ireland and worldwide. For producers to meet their financial targets, increased performance and output is a key issue, now more than ever. To optimise performance in broiler production houses, the effect of environmental and air quality parameters on bird performance and energy consumption must be known to allow farmers make informed management decisions. This paper concentrates on the application precision livestock farming sensors to develop recommendations for improved bird performance and energy consumption in broiler production farms in Ireland. Air temperature, relative humidity, light, air speed and air quality (in particular CO2 and NH3 concentrations) are identified as important parameters for improving bird performance and energy consumption in broiler production houses. Several of these parameters (temperature, relative humidity, CO2 and NH3) were monitored on two farms during the study over the initial 2 weeks of the production cycle. Air quality was often overlooked during the production process, as farmers struggled to limit high heating and feed costs. However, elevated levels of CO2 (>3000 ppm) did not appear to affect broiler growth rates. Additionally, a strong correlation was observed between relative humidity and NH3 (R2 = 0.86 - 0.92). Producers tend to use relative humidity as an indication for NH3 levels and the research shown in this study confirms the close relationship between the two parameters. It is recommended that further data should be gathered from producing units and novel performance technologies should also be investigated.5464 - PublicationEnergy piles: site investigation and analysisDespite 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.
1259Scopus© Citations 15 - PublicationEnergy Foundations - Potential for IrelandWith 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 building
1390Scopus© Citations 4 - PublicationThermal response testing of compromised borehole heat exchangersThe 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.
568Scopus© Citations 3 - PublicationA preliminary study of the effect of groundwater flow on the thermal front created by borehole heat exchangersThis 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.
373Scopus© Citations 8 - PublicationDesign and development of a low-cost divided bar apparatusA divided bar apparatus is deemed to be the most accurate method of measuring the thermal conductivity, λ, (W/mK) of intact rock cores in the laboratory. The divided bar is a steady-state comparative method in which the temperature drop across a disk of rock is compared with that across a disk of standard material of known conductivity. Thermal conductivity test results obtained from rock cores can be used in software programs to determine the design requirements for any medium to large-scale ground-source energy system. This paper describes the design and development of a low-cost divided bar apparatus and compares the values obtained to those achieved by previous researchers and those recommended by EED, a commonly used borehole heat exchanger design software program. The divided bar was designed in accordance with the following principles: keep construction costs low by using readily available materials, develop a simplistic operating procedure to promote continuity of use and cater for the testing of different sized rock cores. As there are currently no recognised testing standards available for operation of a divided bar apparatus, the sample preparation procedure for samples tested on the UCD divided bar apparatus was developed as a proposed standard testing procedure. The proposed procedure amalgamates the developments and suggestions of previous researchers in addition to published test procedures in Ulusay and Hudson (2007), and could possibly contribute towards the development of a standardised procedure for testing on a divided bar apparatus. The test results presented in this paper demonstrate a strong relationship between thermal conductivity and mineral composition with the effects of porosity also having a notable influence on the thermal conductivity of the tested rocks.
850Scopus© Citations 7