Cool roof technology in London: An experimental and modelling study

This is the post-print version of the final paper published in Journal of Energy and Buildings. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2011 Elsevier B.V.One of the primary reasons for the application of cool materials is their energy and associated environmental impact on the built environment. Cool materials are usually applied on the roof of buildings to reduce cooling energy demand. The relative benefits of this reduction depend on the construction of the building, external weather conditions and use of the building. This paper examines the impact from the application of a reflective paint on a flat roof in a naturally ventilated office building in the area of London, UK where the climate is moderate with high heating demand by buildings. The environmental conditions (internal/external air and surface temperatures) of the building were monitored before and after the application of the cool roof during the summer. It was found that internal temperatures were reduced after the application of the cool roof. The building was modelled using TRNSYS and the model was calibrated successfully using the measurements. A parametric analysis was carried out by varying the reflectivity and insulation of the roof and ventilation rate; the heating and cooling demand for a year was calculated using the Summer Design Year for London as the weather file. It was found that cooling demand is significantly reduced, heating demand is increased and the total energy savings vary between 1 and 8.5% relative to an albedo of 0.1 for the same conditions. In free floating (naturally ventilated) buildings summer comfort is improved but there is a penalty of increased heating energy during the winter. Thermal comfort can be improved by an average of 2.5 °C (operative temperature difference for a change of 0.5 in albedo) but heating demand could be increased by 10% for a ventilation rate of 2 air changes per hour. The results indicate that in the case of temperate climates the type, operation and thermal characteristics of the building should be considered carefully to determine potential benefits of the application of cool roof technology. For the examined case-study, it was found that a roof reflectivity of 0.6–0.7 is the optimum value to achieve energy savings in a cooled office, improve summer internal thermal conditions in a non-cooled office (albeit with some heating energy penalty). It indicates that it is a suitable strategy for refurbishment of existing offices to improve energy efficiency or internal environmental conditions in the summer and should be considered in the design of new offices together with other passive energy efficient strategies.Intelligent Energy Europe (IEE

A new rat model for the study of obesity

The currently used raL models of obesity and diabetes are derived from either Zucker or from Koletsky rats. Recently, we identified a spontaneous obese rat from out Wistar colony which is maintained as an inbred stock for the past 75 years. Initially, one of the male progeny in a litter was observed to have abnormal body weight for its age. The parents of this ral were identified, the progeny selectively bred, and a colony has been developed. This is designated as WNIN-0b. The colony is maintained by mating heterozygous animals (+/ob), as the homozygous (ob/ob) were found to be infertile. The trait is carried as an autosomal recessive mutation and the colony is currenfly in F7 generation.Obesity is visible in these mutants around 35 days of age. They are hyperphagic and reach a body weight of 500—600 g by 105 days of age. “Kinky” tail is characteristic of this mutant and this is visible around 50-60 days. Sexual maturity is delayed in female obese mutants, as judged by the day of vaginal opening. The animals are cuglyccmic and show hyperinsulinaemia, hypertriglyceridaemia, arid hypercholesterolemia. Another mutant showing hyperglycemia is also obtained fromthe obese colony. Unlike earlier models which are essentially derived from a randomAbred stock, this is the first report of a rat obese model, developed spontaneously from an inbred strain

Australian Transnational Educational Leadership Roles: Challenges, Opportunities and Experiences

The establishment of higher educational hubs in Malaysia and Singapore has spurred the growth of transnational education (TNE) offerings in Asia, and attracted several Australian higher education providers to set up branch campuses in these countries. In Malaysia, TNE is seen as contributing to economic targets by helping to decrease the outflow of students and currency, and by attracting international students to Malaysian shores (British Council 2012). The provision of higher education through TNE raises issues somewhat distinct from those arising with local provision of higher education. These include the balance of local and foreign educational decision making and its implications for academic staff and for the learning experiences of students. This paper is informed by ‘Learning without Borders: Leadership in transnational education and internationalization of curriculum’, an Australian Office of Learning and Teaching (OLT) funded project undertaken at Curtin University and Swinburne University of Technology, involving Australian campuses and branch campuses. The project investigated staff experiences, expectations and preferences on TNE issues including career path opportunities, teaching and learning implications. The project focused particularly on the development of recognition and support for leadership roles in transnational education and on internationalization of curriculum. The paper highlights some of the TNE and internationalization measures that might enhance staff experiences and student learning

Computational analysis of Variable Thrust Engine (VTE) performance

The Variable Thrust Engine (VTE) of the Orbital Maneuvering Vehicle (OMV) uses a hypergolic propellant combination of Monomethyl Hydrazine (MMH) and Nitrogen Tetroxide (NTO) as fuel and oxidizer, respectively. The performance of the VTE depends on a number of complex interacting phenomena such as atomization, spray dynamics, vaporization, turbulent mixing, convective/radiative heat transfer, and hypergolic combustion. This study involved the development of a comprehensive numerical methodology to facilitate detailed analysis of the VTE. An existing Computational Fluid Dynamics (CFD) code was extensively modified to include the following models: a two-liquid, two-phase Eulerian-Lagrangian spray model; a chemical equilibrium model; and a discrete ordinate radiation heat transfer model. The modified code was used to conduct a series of simulations to assess the effects of various physical phenomena and boundary conditions on the VTE performance. The details of the models and the results of the simulations are presented

Your place or mine: transnational education and the locus of control

In transnational education the place – in both an organisational and a geographic sense – in which educational decisions are made impacts on the academics involved and on student learning. The subject of this paper is learning and accreditation that takes place outside a home university through offshore branch campuses. A case study of two Australian Universities with offshore campuses in Sarawak, Malaysia was undertaken. Policies and procedures were reviewed and an empirical study of the experiences of academics involved was conducted. The study focused on who makes decisions about curriculum content, learning and teaching activities, design and provision of educational resources, and the assessment of student work. Consequences of the organisational relationships for academics involved and for student learning are examined in this paper. On the basis of the study a high degree of local control is recommended, at least for units of study that have operated transnationally several times

CFD Analysis of Spray Combustion and Radiation in OMV Thrust Chamber

The Variable Thrust Engine (VTE), developed by TRW, for the Orbit Maneuvering Vehicle (OMV) uses a hypergolic propellant combination of Monomethyl Hydrazine (MMH) and Nitrogen Tetroxide (NTO) as fuel and oxidizer, respectively. The propellants are pressure fed into the combustion chamber through a single pintle injection element. The performance of this engine is dependent on the pintle geometry and a number of complex physical phenomena and their mutual interactions. The most important among these are (1) atomization of the liquid jets into fine droplets; (2) the motion of these droplets in the gas field; (3) vaporization of the droplets (4) turbulent mixing of the fuel and oxidizer; and (5) hypergolic reaction between MMH and NTO. Each of the above phenomena by itself poses a considerable challenge to the technical community. In a reactive flow field of the kind occurring inside the VTE, the mutual interactions between these physical processes tend to further complicate the analysis. The objective of this work is to develop a comprehensive mathematical modeling methodology to analyze the flow field within the VTE. Using this model, the effect of flow parameters on various physical processes such as atomization, spray dynamics, combustion, and radiation is studied. This information can then be used to optimize design parameters and thus improve the performance of the engine. The REFLEQS CFD Code is used for solving the fluid dynamic equations. The spray dynamics is modeled using the Eulerian-Lagrangian approach. The discrete ordinate method with 12 ordinate directions is used to predict the radiative heat transfer in the OMV combustion chamber, nozzle, and the heat shield. The hypergolic reaction between MMH and NTO is predicted using an equilibrium chemistry model with 13 species. The results indicate that mixing and combustion is very sensitive to the droplet size. Smaller droplets evaporate faster than bigger droplets, leading to a well mixed zone in the combustion chamber. The radiative heat flux at combustion chamber and nozzle walls are an order of negligible less than the conductive heat flux. Simulations performed with the heat shield show that a negligible amount of fluid is entrained into the heat shield region. However, the heat shield is shown to be effective in protecting the OMV structure surrounding the engine from the radiated heat

Combustion chamber analysis code

A three-dimensional, time dependent, Favre averaged, finite volume Navier-Stokes code has been developed to model compressible and incompressible flows (with and without chemical reactions) in liquid rocket engines. The code has a non-staggered formulation with generalized body-fitted-coordinates (BFC) capability. Higher order differencing methodologies such as MUSCL and Osher-Chakravarthy schemes are available. Turbulent flows can be modeled using any of the five turbulent models present in the code. A two-phase, two-liquid, Lagrangian spray model has been incorporated into the code. Chemical equilibrium and finite rate reaction models are available to model chemically reacting flows. The discrete ordinate method is used to model effects of thermal radiation. The code has been validated extensively against benchmark experimental data and has been applied to model flows in several propulsion system components of the SSME and the STME