Adaptive thermal comfort in naturally ventilated hostels of warm and humid climatic region, Tiruchirappalli, India

Abstract

• Comfort range for hostel building was found between 26.1 and 32.8 °C. • The desired temperature was found to be 27.8 °C, while neutral temperature was 29.5 °C. • The comfort limit extended by 2.8 °C if air velocity rises from 0.1 to 1.1 m/s. • Sweating Acceptability extended the thermal acceptability limit from 31.8 to 32.4 °C. • At 26.6 °C temperature about 50% of the fans were found switched on. Thermal comfort is an important factor in hostel buildings when the aim is to maximize the productivity of the students. Due to the extreme weather conditions, achieving thermal comfort in a hostel building in a hot and humid climate is even more difficult. Studies conducted in naturally ventilated hostel buildings in warm-humid climates involved the influence of outdoor air temperature only up to 34.4 °C and have been conducted in a specific season. In contrast, the Tiruchirappalli climate is characterized by a higher range of environmental variables. Therefore, to understand the thermal comfort conditions and usage of the environmental controls in naturally ventilated hostel buildings at the higher range of the environmental variables, a thermal comfort field study spread over one year was carried out at the National Institute of Technology, Tiruchirappalli, India, in twenty-seven hostel buildings. This study relies on field observation and thermal comfort responses from 2028 questionnaires collected from the students between September 2019 to August 2020. The analysis revealed a neutral temperature of 29.5 °C and a comfort range from 26.1 °C to 32.8 °C, indicating a wide range of thermal adaptation than suggested by the National Building Code of India and ASHRAE standard 55. The preferred temperature was 27.8 °C, indicating that students preferred a cooler environment. Acceptability with sweating conditions extended the upper limit of thermal acceptability from 31.8 °C to 32.4 °C. The use of a mosquito net can increase the probability of opening a window. Results indicated that overall behavioral adjustment could extend the comfort limits. The study results would be helpful to develop guidelines and designs for naturally ventilated hostel buildings in warm and humid climates that will contribute to reducing energy demand.