Marine Renewable Energy Ireland search Center

Gaillimh, Ireland

Marine Renewable Energy Ireland search Center

Gaillimh, Ireland
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Ren L.,Marine Renewable Energy Ireland search Center | Hartnett M.,National University of Ireland | Hartnett M.,Ryan Institute
Energy Procedia | Year: 2017

In this study, Decision Tree (DT) was employed to predict surface currents in a -scaled marine renewable energy test site - Galway Bay. In training and testing models, wind speed, wind direction and tidal water elevation from a forecasting model, and observations of surface velocity components during previous hours were taken as input variables; surface velocity components were taken as the output variable. Appropriate value of Complexity Parameter (CP) in decision tree models was determined based on experiments producing the minimum Root-Mean-Square-Error (RMSE) values compared with the radar data. Statistics including RMSE, bias, correlation (R) and Scatter Index (SI) were computed between predictions and radar data to assess predictions. Results indicated that the DT model can produce satisfactory predictions of surface currents. Good performance of DT model indicated that it can be regarded as a promising approach for future applications. © 2017 The Authors.

Kennedy C.R.,Marine Renewable Energy Ireland search Center | O Bradaigh C.M.,University College Cork | O Bradaigh C.M.,Marine Renewable Energy Ireland search Center | Leen S.B.,Marine Renewable Energy Ireland search Center
16th European Conference on Composite Materials, ECCM 2014 | Year: 2014

A combined experimental and computational study on the fatigue of glass-fibre reinforced polymers (GFRP) is presented, with particular emphasis on the effects of water saturation, for use in ocean energy structures. The experimental characterisation consisted (i) of immersion-aging of test specimens for a period of up to two years, using a moderate accelerated aging technique, designed to simulate longer-term seawater exposure of the material, and (ii) fatigue testing of aged and unaged specimens in immersed and non-immersed conditions, with emphasis on identification of fatigue damage evolution. The computational methodology incorporates the development of a multiaxial fatigue damage user material subroutine, based on the static Puck approach, adapted for fatigue by combining (i) fatigue-induced fibre strength and modulus degradation, (ii) irrecoverable cyclic strain effects and (iii) inter-fibre fatigue. Finally the impact of water saturation on the fatigue life of a tidal turbine blade is assessed using a fatigue life model.

Finnegan W.,National University of Ireland | Goggins J.,National University of Ireland | Goggins J.,Marine Renewable Energy Ireland search Center | Clifford E.,National University of Ireland | Zhan X.,National University of Ireland
Journal of Cleaner Production | Year: 2015

In 2015, the milk quota system that is in place in Europe is to be abolished, instigating an increase in milk production. This increase will aid in addressing the world's ever growing demand for food, but will incur increased stresses on the environmental impact and sustainability of the dairy industry. In this paper, an environmental life cycle assessment, which is performed in order to estimate the global warming potential (GWP) associated with 11 dairy products in the Republic of Ireland, is presented. The primary aim of the study is to examine the GWP associated with the processing of raw milk into the various products. However, the GWP contribution from dairy farms producing the raw milk is also included. Therefore, the system boundary utilised in this study is cradle-to-processing factory gate (dairy, farm, raw milk transportation and dairy processing). Furthermore, when performing the analysis, the 11 dairy products are clustered into 6 product groups: fluid milk (whole milk, skimmed and semi-skimmed milk); butter; cheese; cream; milk powders (buttermilk powders, whole milk powders, skimmed milk powders, and chocolate crumb); and whey powders (whey powders and proteins). The total GWP was calculated for each product group and mass allocation was used to derive the GWP of each product within that group. Data from 12 companies (18 dairy processing plants), which account for approximately 92% of the cow's milk processed in the Republic of Ireland, was used in this study to accurately assess the Irish dairy processing industry. From the analysis, it was found that raw milk production accounted for between 80.8% and 97.3% of the total GWP, depending on the amount of raw milk per kg of product. Additionally, raw milk transportation accounted for approximately 0.4% of the GWP, with the remainder contributed by the processing phase. The main contributor to GWP in the processing phase was direct energy use within the plant (electricity, natural gas and other fuel), which accounts for between 91 and 98% of the GWP, depending on the product. Furthermore, even though raw milk production is the most significant contributor to the total GWP of each dairy product, it was observed that energy use and water consumption in the processing phase were of the same magnitude as that of the production phase. © 2015 Elsevier Ltd.

Goggins J.,National University of Ireland | Goggins J.,Marine Renewable Energy Ireland search Center | Finnegan W.,National University of Ireland
Renewable Energy | Year: 2014

Ocean wave energy is one of the world's most powerful forms of energy and the energy density in ocean waves is the highest among renewable energy sources. Wave energy converters are employed to harness this energy and convert it into usable electrical energy. However, in order to efficiently extract the energy, the wave energy converter must be optimised in the design stage. Therefore, in this paper, a methodology is presented which aims to optimise the structural geometric configuration of the device to maximise the average power extraction from its intended deployment site. Furthermore, a case study of the Atlantic marine energy test site, off the west coast of Ireland, is undertaken in order to demonstrate the methodology. Using the average annual wave energy spectrum at this site as the input, the optimum structural geometric configuration was established, along with an analysis of the optimum configuration for different radius devices. In addition, the optimum damping coefficient of the PTO mechanism is determined and the total mean absorbed power for the structure at the site over the entire scatter diagram of data is calculated. © 2014 Elsevier Ltd.

Goggins J.,National University of Ireland | Goggins J.,Marine Renewable Energy Ireland search Center | Moran P.,National University of Ireland | Armstrong A.,National University of Ireland | Hajdukiewicz M.,National University of Ireland
Energy and Buildings | Year: 2016

Directives in the European Union are ensuring that buildings in this region are moving towards nearly zero energy buildings (NZEB). For countries like Ireland, which has a temperate oceanic climate, a key to achieving NZEB is to have high thermal and air tightness performances of the building envelope. Consequently, as the operational energy of the building reduces, the embodied energy (and embodied global warming potential) typically increases as a proportion of the lifecycle energy of the building due to increased embodied energy of the building envelope and the lower operational energy. In order to assess if a design strategy is in fact sustainable, it is becoming essential to evaluate environmental and economic LCA of building design strategies. This paper presents the outcomes of a number of case study buildings in Ireland, which focuses on the full environmental and economic lifecycle assessment of buildings to assess the impact changes in building regulations are having on the contribution of both the construction and operation of a building's lifecycle as they move towards NZEB standards. If designed with a focus on achieving a high thermal and air tightness, a building with an embodied energy intensity less than a building that achieves compliance with 2011 Irish building energy performance regulations can achieve a NZEB standard. © 2016 Elsevier B.V. All rights reserved.

Atan R.,National University of Ireland | Atan R.,Marine Renewable Energy Ireland search Center | Atan R.,Marine Institute of Ireland | Goggins J.,National University of Ireland | And 9 more authors.
Ocean Engineering | Year: 2016

This research presents an assessment of wave characteristics at the 1/4 scale wave energy test site in Galway Bay based on (1) data from a waverider buoy from 2009 to 2013 and (2) data from a high frequency radar system (CODAR) from 2011 to 2013. The main objective of this research is to provide an assessment of annual and seasonal wave characteristics and resource variability at a wave energy site. Such assessments are extremely important for wave energy test sites so as to inform the design, optimisation and maintenance of wave energy converters. An approach for classifying operational, high and extreme wave events is presented. The approach is based on percentage of occurrences of particular wave events and can be applied to any site and any wave parameter. In the present research it is separately applied to wave height and wave power. An additional objective is the validation of CODAR wave data for use in assessment of wave height characteristics; this was achieved by comparing CODAR data with waverider data. The research shows that the authors characterisation methodology is easy to apply and unambiguous to interpret. Due to the significant variation in wave parameters at the site from season to season and year to year, operational, high and extreme conditions are presented for the 5-year measurement period, individual years and individual seasons. The research also shows that wave heights determined from CODAR show good agreement with those from a waverider buoy and may be relied upon for accurate site characterisation. © 2016 Elsevier Ltd. All rights reserved.

Finnegan W.,National University of Ireland | Goggins J.,National University of Ireland | Goggins J.,Marine Renewable Energy Ireland search Center
Applied Ocean Research | Year: 2015

In the design of any floating or fixed marine structure, it is vital to test models in order to understand the fluid/structure interaction involved. A relatively inexpensive method, compared to physical model testing, of achieving this is to numerically model the structure and the wave conditions in a numerical wave tank. In this paper, a methodology for accurately replicating measured ocean waves in a numerical model at full scale is detailed. A Fourier analysis of the measured record allows the wave to be defined as a summation of linear waves and, therefore, Airy's linear wave theory may be used to input the wave elevation and associated water particle velocities. Furthermore, a structure is introduced into the model to display the ability of the model to accurately predict wave-structure interaction. A case study of three individual measured waves, which are recorded at the Atlantic marine energy test site, off the west coast of Ireland, is also presented. The accuracy of the model to replicate the measured waves and perform wave-structure interaction is found to be very high. Additionally, the absolute water particle velocity profile below the wave from the numerical model is compared to a filtered analytical approximation of the measured wave at a number of time-steps and is in very good agreement. © 2015 Elsevier Ltd.

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