Daylight illuminance modelling for the United Kingdom and Europe
This thesis highlights the benefits to occupants and owners of buildings who utilise daylight effectively. Many cases of absence are related to depression or Seasonal Adjustment Disorder(SAD) which results from inadequate exposure to daylight in the work place. The use of artificial lights has been linked to minor as well as more serious ailments such as cancer and increases in cases of miscarriage. The use of daylight in buildings from economic and environmental perspectives is the main concern of the thesis. The work and analysis of this thesis have produced two new illuminance models. In addition detailed illuminance and irradiance data for Central Scotland were recorded which has previously not been available. A comprehensive study of luminous efficacy research was undertaken in Chapter 3 which evaluated a complete range of models. Furthermore the luminous efficacy of various UK and international sites were compared to examine climatic differences. The development of a new slope illuminance model which more accurately predicts external illuminance for all sky conditions was shown to perform consistently better than previous models. This was due to the new model's treatment of the sky background diffuse component utilising an anisotropic form as opposed to the traditional assumption of an isotropic sky background diffuse component. The availability of sky luminance distribution data from introduction of sky scanners enabled innovative daylight illuminance factors to be developed. These factors model the distribution of the sky's hemisphere under all levels of cloud cover and calculate the internal illuminance taking into account window size, glazing type, orientation and time of the day. The development of the daylight illuminance factors has been shown to significantly improve the energy efficient design of buildings in comparison to the current practice of employing the sky factor method. The daylight illuminance factors were used in a modelled building design scenario to assess their performance and to examine energy efficient design. Lighting controls and various glazing types were analysed to study their impact on a buildings energy consumption. This study also incorporated an embodied energy analysis which considered the energy consumption of windows in manufacture and operation.