Showing papers by "Marina Neophytou published in 2009"

Dispersion Experiments in Central London: The 2007 DAPPLE project

Abstract: In the event of a release of toxic gas in the center of London, emergency services personnel would need to determine quickly the extent of the area contaminated. The transport of pollutants by turbulent flow within the complex streets and building architecture of London, United Kingdom, is not straightforward, and we might wonder whether it is at all possible to make a scientifically reasoned decision. Here, we describe recent progress from a major U.K. project, Dispersion of Air Pollution and its Penetration into the Local Environment (DAPPLE; information online at www.dapple.org.uk). In DAPPLE, we focus on the movement of airborne pollutants in cities by developing a greater understanding of atmospheric flow and dispersion within urban street networks. In particular, we carried out full-scale dispersion experiments in central London from 2003 through 2008 to address the extent of the dispersion of tracers following their release at street level. These measurements complemented previous studies because 1...

Perturbation solutions of Poiseuille flows of weakly compressible Newtonian liquids

Abstract: Both the planar and axisymmetric isothermal Poiseuille flows of weakly compressible Newtonian liquids with constant shear and bulk viscosities are solved up to the second-order. A linear equation of state is assumed and a perturbation analysis of the primary flow variables is performed using compressibility as the perturbation parameter. The effects of compressibility, the bulk viscosity, the aspect ratio, and the Reynolds number on the velocity and pressure fields are studied and comparisons are made with available analytical results.

Classification of buildings in Cyprus based on their energy performance

Abstract: This paper describes the work that will be done in a research project, which will facilitate the implementation of the EPBD through the calculation of the existing Cyprus Building Stock energy behaviour. This will be achieved through the selection of a representative sample of 500 housing units and the collection of data through questionnaires, followed by statistical analysis of the data and the interpretation of the results. The key parameters that will form the different clusters are climatological zone, type, age and size of each housing unit. The statistical interpretation of the collected dataset will provide insights with regards to the energy behaviour of the building stock for each class. The ultimate goal is to suggest the number of classes for the Energy Performance Certificate and the upper and lower energy consumption limits for each class. Moreover, the formulation of an energy behaviour map, the consideration of the historical development of the buildings behaviour and the improvement of the insulating materials and solutions, will lead to the readjustment of the values, particularly for the best two classes, so as not only to reflect today’s reality, but also to show the intent of the state to improve the level of the construction industry. In this study, the various types and quantities of thermal insulating materials utilized in Cyprus, for the time interval 01/01/08–30/09/08, are also reported. The data were extracted from applications made by individuals who claimed financial subsidy. A random specimen of 400 applications was evaluated: 55% refer to existing housing, and 45% to new buildings. The different kinds of materials used for insulating floorings, walls and roofs, in different regions of the island were evaluated. The principal observation made is the extensive use of double glazing for doors and windows.

Ventilation characteristics of the built environment and their effects on the urban microclimate

Abstract: The thermal conditions within cities, as well as the energy efficiency of buildings, are determined by the urban climate, which is in turn influenced by the thermal-fluid characteristics of the built environment and particularly the transfer effects to the atmosphere. A good example of this interaction is the urban heat island phenomenon. In this case heat generated from urban activities has a direct impact on the urban microclimate, resulting in increased night time temperatures and a reduction in the observed temperature range. In order to understand the interaction between the built environment and the urban microclimate, one needs to consider: (1) the energy efficiency of the built environment and mainly the phenomena of heat transfer through radiation; and (2) the ventilation capability of the urban environment and the effects of different building geometries. The study presented in this paper is concerned with the ventilation of the built environment and involves Particle Image Velocimetry (PIV) measurements under street canyon flow conditions in a flow channel.