Ph D Thesis Abstract

Thermal comfort and Adaptive Use of Controls in summer: An investigation of Apartments in Hyderabad
Ph D Thesis by Madhavi Indraganti, 2009.
Abstract:
There is little thermal comfort research in residential environments reported from India. Energy consumption in Indian residential buildings is one of the highest, increasing at a phenomenal rate. Indian standards advocate two narrow ranges of temperatures for all building and climate types.
A field study in summer and monsoon was conducted following Class –II protocols, for three months in 2008, in naturally ventilated apartment buildings in Hyderabad. Over a hundred subjects involved, giving 3962 datasets.
In May, most of the subjects were uncomfortable, preferring a temperature on the cooler side of the neutrality, despite accepting their thermal environments. Thermal sensation, preference and acceptance improved in monsoon. The regression analysis yielded the comfort band to be 26 -32.45 °C with the neutral temperature at 29.23 °C. This is way above the Indian standard limits (23- 26°C). The PMV always overestimated the sensation vote. These findings have far reaching energy implications on building and HVAC systems design and practice in a developing country like India.
Humidity did not affect comfort sensation much in summer, as it was hot and dry. Conversely, increase in humidity adversely affected the thermal comfort in June. When the available adaptive opportunities were sufficient, the subjects living in top floor flats showed a higher neutral temperature.
Age, gender and tenure of the occupants correlated weakly with thermal sensation. Economic level of the subjects showed significant effect on the thermal sensation, preference, acceptance and neutrality.
Occupants’ responses for other environmental parameters often depended on their thermal sensation, often resulting in a near normal distribution. The subjects displayed acoustic and olfactory obliviousness due to habituation, resulting in higher acceptance.
The occupants adapted through clothing, metabolism and the use of environmental controls. At comfort temperature, maximum use of openings was found. Use of controls was critically impeded by lack of privacy and safety. The building’s ‘restrained adaptive opportunity’ seriously hampered the occupant’s thermal satisfaction and adversely affected the sensation vote. Use of electrical controls increased with temperature, and was impeded by their poor efficacy and noise, occupant’s attitudes and economic affordability. A/c and air coolers were used mostly in top-floors.
Behavioural adaptation was better in summer and was restricted in higher economic groups always. Clothing adaptation was impeded by many socio- cultural and economic aspects. Thermal tolerance was limited in subjects using A/c s, resulting in “thermal indulgence”. This study calls for comfort standards and special adaptation methods for top-floor flats.