Indoor Thermal Comfort Range for Naturally Ventilated Residences in Warm and Humid Climate of Mumbai, Maharashtra, India

Abstract

Every third house in Indian cities will have an air conditioner by 2030, this poses great challenges of energy consumption and related emissions. 68.7% of the total GHG emissions in India (2014) are by energy sector, and half of that were due to electricity and heat generation. As the energy demand in India is expected to become 3.5 times from 2014 to 2030, it is important to reduce the energy consumption beyond introducing renewable energy sources (WRI-CAIT). Naturally ventilated and thermally comfortable habitat is the need of our times. Developing appropriate and local based thermal comfort standards for naturally ventilated spaces will aid in energy conservation and thereby a sustainable development. The current Indian indoor thermal comfort temperature standards do not reflect the diversity weather conditions (5 climatic zones) in India. The National Building Code of India suggests a common model of comfort temperature for all types of naturally ventilated building in any climatic zone of India. Hence there is a need to derive local thermal comfort range specific to climatic zones of India for residential buildings. This study focuses on developing the adaptive thermal comfort range derived recently from the field survey of occupants of existing naturally ventilated residential buildings in warm and humid climate of Mumbai. The adaptive thermal comfort field survey (class II) was conducted with acclimatized adult residents of naturally ventilated buildings at different times of the day and in different seasons to study overall effect of weather of Mumbai. This survey considered physical, psychological, physiological, and behavioral aspects relevant to thermal comfort studies. The adaptive thermal comfort neutral temperature was derived in this study as 28.1°C ET* and 90% comfortable range is 26.1 to 30.1°C in terms of ET* for the naturally ventilated residential buildings of warm and humid climate of India.