Climate-resilience of Dwellings in Transition and the Thermal Behaviour of their Inhabitants

Abstract

Thermal comfort is critical for the well-being, and productivity of the inhabitants. Traditional dwellings constructed using local, low-carbon materials have for decades provided comfortable indoor thermal environment to its inhabitants through passive design. Traditional materials are increasingly being replaced by standardised, industry-manufactured, energy-intensive materials. The modern buildings are rarely designed for the climate of the region and are predominantly equipped with electro-mechanical appliances to alter the indoor thermal environment. Transitions in the building envelopes alter the thermal performance of the dwelling. Whether the changing thermal environment resulting from transitions in the buildings accompanied by the reliance on active adaptive strategies affect the thermal expectations of the inhabitants is not known. The transitioning built environment, the changing lifestyles and thermal expectation of the occupants and the looming climate change affect the thermal comfort of occupants. Three transitioning rural settlements across three climate zones in India were selected for the study. Transitions in these settlements were studied through field investigation, habitat surveys, and historical satellite imagery. Representative traditional and modern dwellings were selected to study the effect of transitions on the embodied energy and thermal performance of the dwellings. The thermal performance of the transitioning dwellings to prevailing and changing climate was investigated through real-time measurement of environmental parameters and dynamic building simulation. The influence of long-term exposure to the thermal environment that prevailed in the traditional and modern dwellings, accompanied by the dependence on passive or active adaptive strategies on the thermal expectation of the inhabitants was investigated through general and point-in-time thermal sensation surveys of occupants. Various drivers and consequences of transitions were identified both through literature survey and field studies. The application of secondary data, field surveys and historical satellite imagery to interpret transitions was demonstrated. A methodology to study the thermal performance of transitions dwellings was developed, and the adoption of heating and cooling load calculated based on adaptive degree-days was demonstrated. The investigation revealed that traditional dwellings performed better than the modern dwellings across climate zones. Climate change further increased the cooling load in warm climates while reducing heating load in cold climates. Both transitions and climate change had a compounding effect on the thermal performance of the dwellings in temperate and warm-humid climate zones. The study revealed varying adaptive behaviour between the two occupant groups and long-term exposure to their respective thermal environment influenced the thermal perception of occupants. The study highlights the importance of studying the nexus between climate, habitat, and inhabitants. This is critical in understanding thermal comfort, energy implications and emissions associated with the occupation of the buildings. Studying this nexus and variations in them are imperative in designing buildings for the future that are low carbon, sustainable and resilient to climate change.