An adaptive thermal comfort model for the tropical climatic regions of India (Köppen climate type A)

• Five existing adaptive comfort equations are examined for Indian conditions.
• Predictions of comfort equations compared with field survey comfort temperatures.
• Expected energy savings are estimated using adaptive comfort degree days.
• Results show the overall suitability of EN15251 adaptive standard.

Adaptive comfort standards have been gaining wider acceptance and are now considered an integral part of main stream comfort research. Several adaptive comfort equations have been developed, some as part of international comfort standards and some for specific climatic regions. In the current work, an attempt was made to find a best fit among available comfort equations for predicting occupant comfort in the tropical climatic regions of India. Comfort temperatures found in surveys done across tropical India were compared to comfort temperatures computed from five different adaptive comfort equations. Additionally, to estimate energy savings possible through implementation of adaptive comfort standards, adaptive comfort degree days (ACDD) were calculated across seven Indian cities using comfort temperature predictions from the five equations. Put together, results from these two analyses showed that the comfort equation from EN15251 may be used as a reasonable predictor of comfort in naturally ventilated buildings of hot–humid Indian regions and such use would also result in major energy savings. It is proposed that till further studies in India provide more detailed results, the EN15251's standard for naturally ventilated buildings may be used as a suitable option for Indian conditions. Formalisation of appropriate adaptive comfort standards for India would be a significant asset to the sustainable development of this country.