Steve Sharples

Daylight in Atrium Buildings: A Critical Review

Abstract Using daylight as part of an integrated and controlled lighting strategy is a key component of a sustainable, environmental approach to architectural design. An atrium is potentially a major source of daylight for deep plan buildings and offers other environmental benefits in terms of solar gain, reduced energy losses and natural ventilation. For daylight design, the key atrium components are the roof fenestration system, the geometry of the atrium well, the reflectance of the wells surfaces and the daylight levels achieved in spaces adjacent to the well. This review will consider the research relating to daylight in atrium buildings that has taken place during the last 15 years since ca 1990, much of which has been reported in the Architectural Science Review.

Occupants’ perceptions and expectations of a green office building: a longitudinal case study

Sustainability as a concept can become devalued if occupants’ engagements with a building are not satisfactory. This article investigated how occupants’ attitudes towards a buildings ‘green’ identity interacted with the buildings performance and the occupants’ overall satisfaction of the building. The research is based on a longitudinal study of nearly 2000 staff working in two UK Government office buildings that had received BREEAM ‘Excellent’ ratings. The research programme involved interviews and repeated surveys over a 2-year period. The results indicate how the gap between occupants’ expectations and their perceptions of a green building can affect their satisfaction with the building. Furthermore, it is shown that occupants’ disengagement with the buildings green identity can also, eventually, impact on the buildings sustainable performance.

The geometry of the shading of buildings by various tree shapes

Abstract This paper describes a design tool to be used in assessing the shading effects of trees in relation to buildings. More specifically, an interactive computer program has been written which determines the area and position of the shadows cast by a tree or a group of trees on a surface of any orientation and inclination. The program outputs numerical and graphical hourly results at any time of the day between the sunrise and the sunset, for any day of the year, at any location on the earth for any relative positioning between the tree and the building. The program allows four different shapes of tree (spherical, cylindrical, upright cone or reversed cone) or any combination of these fundamental shapes to be used.

Reflectance distributions and vertical daylight illuminances in atria

In this study parametric changes were made to the distribution of the reflectances of diffuse vertical surfaces in the wells of model square atria placed in an artificial sky. The effects of these changes on the vertical daylight levels at various heights for central positions were examined. Painting the atrium surfaces with alternating, equal width bands of white and black matt paint created the reflectance distribution variability. The widths of the bands were gradually reduced, although the 50:50 black to white ratio was kept constant. The different distributions of reflectances were found to have very little effect on vertical daylight factor and internally reflected component values low down in the atrium well. For some of the higher measurement locations large differences were observed between the different reflectance distributions. Generally, as the bands became narrower and more numerous the daylight levels converged towards values that would be predicted from standard formulae using the area-weighted reflectance of the atrium.

Thermal performance of traditional and contemporary housing in the cool season of Zambia

Abstract It is a generally held view that, in tropical countries, traditional housing is more sympathetic to the prevailing climate compared to contemporary housing. This is because the contemporary house design has typically originated from temperate climates. Empirical studies have been performed on typical traditional and contemporary houses in Zambia (in the cool season) to test whether this hypothesis holds true for Zambia, which experiences a tropical upland climate. Internal climatic conditions were measured in each house. Results show that the contemporary house performed better in the cool season than the traditional house. The external temperatures were more satisfactory than the internal temperatures. These results were further investigated using a thermal comfort survey in traditional and contemporary housing.

A thermal comfort field survey in the cool season of Zambia

Abstract A thermal comfort field survey in Zambia, a country which experiences a tropical upland climate, is described. The survey was done in the cool season (June/July) in the city of Kitwe situated in the north of the country, using the Bedford scale. The neutral temperature was found to be 22.2 °C and the comfort zone was 19.7–24.7 °C. The survey also found that males and females have the same neutral temperature.

The development of a device for measuring solar heat gain and shading coefficients of windows in scale models

Abstract An experimental method for estimating the solar heat gain and shading coefficients for scale-model fenestration systems is described. The method is based on an experimental device, the fenestration radiometer, that is sensitive to either shortwave or longwave radiation (spectrally independent). Another important characteristic is its ability to integrate the incident radiation over its entire surface area, making it adequate for dealing with novel daylighting technologies (e.g., light shelves, mirrored louvres) under real non-uniform sky conditions. The values of solar heat gain and shading coefficients presented in this paper are notably similar to the ones presented by other authors using different methods.

The natural ventilation performance of buildings under alternative future weather projections

Different climate change projections, such as UK Climate Impacts Program (UKCIP02) and 2009 UK Climate projections (UKCP09), have generated a large quantity of data that represent a range of possible future weather scenarios. This article investigates the potential consequences of alternative scenarios for the natural ventilation of non-domestic buildings. The article considers future natural ventilation rates in example buildings, the risk of summer overheating and whether natural ventilation will be a viable thermal control option for future summers. The wind is obviously a key driver of natural ventilation, and a necessary component of building simulation weather files. Problems associated with the generation of wind data from UKCP09 for the natural ventilation analyses are discussed and the influence of differences in weather files on predicted performance considered. These differences are important to the understanding of the consequences for the wider use of UKCP09 derived weather data for building energy evaluation. Practical applications: Weather data are widely used in practice to evaluate the potential and performance of natural ventilation in non-domestic buildings. The predicted differences in future weather data will have direct implications for the design of naturally ventilated buildings, and engineers will need to be aware of the possible implications these climatic differences will create.

Urban Environmental Quality: Perceptions and Measures in Three UK cities

The recent promotion of city center living within United Kingdom (UK) policy has led to commensurate interest in the quality of the urban environment, particularly in the impact and influence that environmental quality has on quality of life and urban sustainability. This paper presents an overview of a study into environmental quality, looking at the environmental conditions and the opinions and experiences of people who live in three of the UK’s major cities; London, Sheffield and Manchester. Environmental quality is both subjective and objective in its nature, and it is this combination that is of particular interest to this study. An innovative multi-method approach, combining qualitative and quantitative data collection techniques, has been developed and employed. Environmental monitoring (indoor and outdoor air quality and noise levels) was undertaken alongside participant lead photo-surveys, sound-walks and semistructured interviews with city center residents. The case studies provide a detailed insight into the components that influence environmental quality; both perceived and measured. The collection and analysis of data has led to the production of ‘local environmental quality maps’ - spatial representations of local and expert knowledge on urban environmental factors. These maps offer a way to feed different perspectives on environmental issues to decision makers for future policy development. The findings of this study help to understand the influence environmental quality has on quality of life, this in turn can aid urban policy, planning and design. The wider implications of this study to the concept of urban sustainability are also discussed.

Airtightness testing of very large buildings: a case study:

The airtightness of a building envelope impacts upon uncontrolled air leakage, associated ventilation energy losses and occupant thermal comfort. The scale of these problems in large buildings would be expected to increase in relation to the potential size of possible leakage areas. Recent changes to UK Building Regulations have required new, large, nondomestic buildings (/ 1000 m2 floor area) to meet a specified standard of airtightness. A building’s airtightness is conventionally assessed using a steady state fan pressurization technique. There was some discussion in the airtightness testing industry that the upper practical limit of large buildings capable of being tested might be around 5000 m2 due to technical issues relating to fan size, power requirements, transportation and noise. The feasibility of testing very large buildings (over 5000 m2) with a steady state fan technique has been questioned. This paper demonstrates that such testing is feasible by describing the development, calibration and application of a 2 m diameter fan pressurisation system. The fan was tested on the largest building in the world (floor area 57 440 m2) ever to have its airtightness determined by steady state fan pressurization. Practical Application: The changes to Building Regualtions Part L2 that came into effect on 1st April 2002 raised the profile of the pressure testing of large buildings for airtightness. There were doubts raised concerning the feasibility of pressure testing very large buildings but the paper demonstrates that it is technically and practically possible.