Stephen Sharples

Urban form, thermal comfort and building CO2 emissions - a numerical analysis in Cairo:

This paper describes a modelling analysis of the role different urban forms might play in reducing building CO2 emissions. The study was based on a residential building in a Cairo neighbourhood under summer conditions and developed a base case urban layout covering an area of 1 km2. Three alternative urban strategies were then created around the same residential building. The software package EnviMet was used to assess external microclimate and thermal comfort conditions in each urban layout. Localised weather files were then created as inputs to the dynamic thermal modelling package DesignBuilder, which predicted the CO2 emissions associated with mechanical cooling to achieve comfort in the building. It was possible to observe some differences in CO2 emissions as a result of the different urban forms.

Risk and Uncertainty in Sustainable Building Performance

Decision-making in the design of sustainable building envelopes will mostly consider the trade-off between initial cost and energy savings. However, this leads to an insufficiently holistic approach to the assessment of the sustainable performance of the building envelope. Moreover, the decisions that designers face are subject to uncertainties and risks with regards to design variations. This research examines a range of concepts and definitions of risk, uncertainty and sustainability in the context of climate, building construction and overheating. These concepts are then combined to objectify a range of risks and uncertainties affecting the decision. A simple computer model was used to analyze different building cladding constructions in terms of an overheating risk inside a building. The paper concludes by considering how the cladding materials may be chosen to optimize a model that will aid decision-making in design. The research suggests that none of the cladding systems would completely eliminate the risk of overheating for a range of climate change scenarios.