Passive cooling potential in buildings under various climatic conditions in India

Passive cooling is a versatile technology through which energy demands to achieve the thermal comfort in a building can be minimized in places like India, where different climatic zones exist. This paper presents the outcome of various research works carried out in the field of evaporative cooling, nocturnal radiative cooling, and phase change material (PCM) based free cooling of buildings under various climatic conditions. Further, the developed empirical equations/correlations for determining the critical design parameters pertaining to the above said passive cooling technologies are summarized in order to provide a panoramic view. The achievable monthly and yearly average cooling potential through the implementation of direct evaporative cooling, nocturnal radiative cooing and PCM based free cooling system are estimated and reported for five selected cities (Chennai, Bangalore, New Delhi, Jaipur, and Jammu and Kashmir) in India, based on their corresponding weather data. It is inferred that Jaipur with hot and dry climatic zone has the highest yearly average passive cooling potential of 251 W m−2, whereas Chennai with warm and humid climate zone has 127 W m−2. In addition, concept of a novel hybrid passive system is presented along with the strategies required in the present scenario to promote passive building concepts. This comprehensive evaluation of cooling potential helps the researchers to select the appropriate passive cooling technologies based on the influencing parameters with respect to local climatic zones.