Microclimate and thermal perception in courtyards located in a tropical savannah climate.

Abstract

Courtyards have been used over many centuries as an interesting architectural feature that extends the living area, with good opportunities for relaxation, contemplation, and also for social interactions in such interface with the outdoor environment. Those areas can also act as climate modifiers and have tempering effects in hot regions. Depending on their geometrical features, courtyards can promote excellent shading and natural ventilation opportunities in tropical regions. This study is focused on the evaluation of two historic courtyards with very distinct solar exposure in a city located in a tropical savannah climate. Field monitoring was carried out alongside surveys with visitors to the courtyards. Results showed the potential of both courtyards in reducing the level of heat stress during peak daytime hours with their climate tempering function. The deeper courtyard yielded steadier cooling effect during daytime than the shallower one. Heat stress, here interpreted in terms of the universal thermal climate index (UTCI) was also more reduced in the deep courtyard. For the subjective part, there was a larger fluctuation of thermal sensation votes for a low level of heat stress in the shallower courtyard but less so and even an opposite pattern for higher heat stress. In essence, the geometric shape of the evaluated courtyards was considered to be paramount to provide thermal attenuation to their visitors due to the interplay between shading and solar access, even though the effect was not observed in their TS votes for increasing heat stress.