This paper presents life cycle assessment (LCA) results of design variations for a 1.5-MW wind turbine due to the potential for advances in technology to improve their performance. Five LCAs have been conducted for design variants of a 1.5-MW wind turbine. The objective is to evaluate potential environmental impacts per kilowatt hour of electricity generated for a 114-MW onshore wind farm. Results for the baseline turbine show that higher contributions to impacts were obtained in the categories of ozone depletion potential, marine aquatic eco-toxicity potential, human toxicity potential and terrestrial eco-toxicity potential compared to technology improvement opportunities (TIOs) 1-4. Compared to the baseline turbine, TIO 1 with advanced rotors and reduced tower mass showed increased impact contributions to abiotic depletion potential, acidification potential, eutrophication potential, global warming potential and photochemical ozone creation potential, and TIO 2 with a new tower concept involving improved tower height showed an increase in contributions to abiotic depletion potential, acidification potential and global warming potential. Additionally, lower contributions to all the environmental categories were observed for TIO 3 with drivetrain improvements using permanent magnet generators while increased contributions towards abiotic depletion potential and global warming potential were noted for TIO 4 which combines TIO 1, TIO 2 and TIO 3. A comparative LCA study of wind turbine design variations for a particular power rating has not been explored in the literature. This study presents new insight into the environmental implications related with projected wind turbine design advancements.

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Citation: Iyi, Draco, Hasan, Reaz and Penlington, Roger (2012) Interaction effects between surface radiation and double-diffusive turbulent natural convection in an enclosed cavity filled with solid obstacles. In: International Symposium on Advances in Computational Heat Transfer ICHMT, 1-6 July 2012, Bath, England. URL:This version was downloaded from Northumbria Research Link: http://nrl.northumbria.ac.uk/8446/ Northumbria University has developed Northumbria Research Link (NRL) to enable users to access the University's research output. Copyright © and moral rights for items on NRL are retained by the individual author(s) and/or other copyright owners. Single copies of full items can be reproduced, displayed or performed, and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided the authors, title and full bibliographic details are given, as well as a hyperlink and/or URL to the original metadata page. The content must not be changed in any way. Full items must not be sold commercially in any format or medium without formal permission of the copyright holder. The full policy is available online: http://nrl.northumbria.ac.uk/policies.html This document may differ from the final, published version of the research and has been made available online in accordance with publisher policies. To read and/or cite from the published version of the research, please visit the publisher's website (a subscription may be required.) ABSTRACT The work reported here is a 2D numerical study on the buoyancy-driven low speed flow of humid air inside a rectangular cavity partially filled with solid cylindrical objects and whose vertical walls are maintained at 1.2 and 21 o C. This is a case of double diffusion where both temperature and concentration gradients are significant. Detailed calculations were carried out and results compared with reliable data, with the aim of investigating the influence of surface emissivity on heat and moisture transport. The Rayleigh number of the fluid mixture (air and water vapour) based on the height of the vertical wall is found to be 1.45 x 10 9 . In the computations, turbulent fluxes of the momentum, heat and mass were modelled by low-Re (Launder-Sharma) k-ε eddy viscosity model. The effect of radiation has been found to be significant even for the moderate temperature difference of 19.8 o C between the hot and the cold walls with the humid air participating in the radiation heat transfer. Variations of average Nusselt number and buoyancy flux are analysed and profiles of turbulent quantities are studied in order to observe the net effect of the intensity of turbulence. It has been found that a change in surface emissivity influences the humidity distribution and heat transfer within the cavity. It was also observed that during natural convection process the air/water vapour combination results in an increase in the heat transfer as compared to pure natural convection. An increase in he...

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