Seasonal comfort temperature and occupant's adaptive behaviour in a naturally ventilated university workshop building under the composite climate of India

Abstract

In the present research work, the authors investigated the seasonal thermal environment and thermal perception of university subjects in a naturally ventilated workshop building under the composite climate of India. Total 1460 subjective responses were collected during the field study in the year, 2019. Standard Effective Temperature (SET*) has been used as a rationally derived thermal comfort index to study the combined effects of air temperature, relative humidity and airspeed on perceived thermal sensation and occupant's preference under high metabolic rates. Probit analysis showed more than 80% of subjects were voting comfortable (±1 Thermal sensation votes) when SET* ranged between 25°C-33 °C. Seasonal mean comfort temperature varied more than 4.8 °C, while, preferred temperature was noted about 3 °C lower than their mean Griffiths comfort temperature. The adaptive relation developed from the collected database under high metabolic activities was compared with existing national and international comfort standards. The slope coefficient for adaptive relation was observed close to the adaptive model of ASHRAE Standard 55–2017 but lower than the National Building Code of India, 2016. Further, adaptive use of fans and windows were analyzed using logistic regression models and predicted about 80% of fans and windows were in operation at 30 °C. To confirm the adaptive mechanism, the interrelation of other contextual factors like gender, clothing insulation, airspeed, metabolic activities, etc. to thermal comfort expectations of subjects were also studied.