Characteristics of thermal comfort in the warm and humid climate of North-East India

The building sector is considered to be one of the most energy-intensive sectors across the world. The building sector consumes about 40% of the world's primary energy and is responsible for a third of total CO2 emissions. Unprecedented high temperatures and heat waves experienced in many parts of India have disrupted everyday life and increased the energy consumption of buildings further. This posed a big question on the persisting indoor environment quality. North-East India is developing very rapidly, and the government of India is also looking to develop it as a hub to connect South Asian countries. The present study is conducted in Tezpur's naturally ventilated office buildings in warm and humid North-East India. Year-long thermal comfort surveys were carried out in 12 naturally ventilated office buildings, collecting 790 samples from July 2016 to June 2017. Data analysis shows that for Tezpur, neutral temperature through regression analysis and Griffiths method is 26.4°C. Tezpur offices' preferred temperature and relative humidity are 24°C and 55%, respectively. Probit analysis showed that occupants are more adaptive toward the warmer side of the thermal sensation scale. It was also found that the office subject's clothing behaviour was a non-linear function of temperature and impacted by local discomfort, creating a temperature difference between the occupant and back wall surface temperature. Data analysis also concluded that ceiling fan use increases exponentially as the indoor globe temperature in the offices reaches 24°C and plateaus or reaches almost 100% at the indoor globe temperature of 32°C.