Thermal Comfort Study in Post Disaster Housing in the Southern Coast of Sri Lanka

The Indian Ocean Tsunami in 2004 had a great impact on the local land formation, vegetation and settlement patterns in Sri Lanka. The re-housing developed to settle the displaced people were carried out in mass scale over a period of two to three years. By and large the criteria for re-settlement had little or no consideration for thermal comfort and climate change. This study was conducted with the aim of identifying the features in the building that causes overheating and features that has the potential to mitigate overheating.A thermal comfort field survey was conducted in selected house types in Boosa and Dadella in Galle, Madihe in Matara and Kirinda in Tissamaharama during the months that presented the most extreme climate conditions during the year. The physical characteristics of thirteen houses were explored; indoor thermal conditions were monitored with the aim of assessing the overall thermal performance of the houses.Findings showed the need to start at the neighbourhood level and the importance of the building envelope in achieving thermal comfort. Implications for design focus on guidelines for controlling the negative effects of the microclimate into the interior habitable spaces, together with the need for prescriptive thresholds for the building envelope

Climate-sensitive urban public space : a sustainable approach to urban heat island mitigation in Colombo, Sri Lanka

Manipulating the urban fabric is fundamental to mitigate and adapt to the warming trend in the growing high-density tropical cities. However, excessive data needs, weak analytical methods and the un-coordinated planning regimes pose barriers to achieving this aim. The main aim of the research is to bridge the gap in urban design-climate links, being translated into guidelines for real-world applicability in a background climate affected by global warming. The study is limited to the warm humid tropical climate of Colombo, Sri Lanka, as the experimental context for the research. The main research questions are related to; the microclimatic background condition under current and future warming scenario; sensitivity of the key urban morphology variables that will define and drive the decision making process; and the planning and policy implications that link climate and urban design. The study employs the Local Climate Zone (LCZ) system as a method of contextual analysis, together with LCZ-based morphology simulations (ENVI-met), utilising Mean Radiant Temperature (MRT) as the key dependent variable. Statistical analyses (SPSS) of the results test the applicability and sensitivity of urban morphological variables to help mitigate / adapt to local and global warming. The findings indicate that the Sky View Factor is the most influential urban indicator of local climate. In general, night-time shows better correlation with MRT. The nature of the Pervious Surface Cover has little or no effect on reducing MRT. And, the correlation of variables with MRT is stronger in a climatic background affected by global warming. The work contributes a ‘conceptual framework’ for the deeper understanding of the effect of building morphology on local level warming in the tropics. Policies that give effect to these findings are presented in a manner that requires minimal data input. Protocols for mapping of LCZs and relative warming effects, and sensitivity analysis of key design parameters for the mitigation of UHI in the tropics are presented. The socio-economic and planning practice implications of a LCZ-based planning approach are explored

Indoor comfort implications of urban microclimate: case study of office buildings in Colombo

The equatorial tropics are experiencing an explosive urban grol1Jth. With intensified urbanisation comes a rapid increase in atmospheric carbon, dl1Jindling resources and concerns over energy seainty. In this context the need to achieve thermal comfort I:y the adoption of passive strategies assumes a great significanc

with reference to selected Contemporary Residential Spaces in Colombo, Sri Lanka

Visual perception of a space is influenced by the composition and behaviour of light. Daylight as a natural element, creates different atmospheres in the same space by its variation of intensity, colour, and direction. It creates dynamic shadow patterns, fluctuating brightness and contrast levels. Although the capacity to create variation - therefore contrast, is an important characteristic of daylight - it is often neglected in research, where comfort and visual performance take prominence. This is a research initiative to emphasise the value of daylight variation on spatial quality and human perception. The research adopts a two-step process, where, digital images are first mapped to generate contrast diagrams, and secondly, the generated digital images form the basis for a survey utilising a seven-point semantic differential scale, to explore the relationship between daylight variability and human perception. The temporal variation of daylight is explored by diagramming the spatial images at selected times of the day and year. The scope of the study is limited to selected contemporary residential spaces and focus on the manner of integrating daylight into spaces. Results show that a direct relationship between daylight variability and human perception for side lit spaces is not evident, yet it is evident in top lit options