Study of the thermal performance of closed courtyard of institutional campus in Dhaka

Abstract

Dhaka is a growing city and expanding in an uncontrolled way. Due to land scarcity buildings are now becoming high rise especially private educational institutions. Educational Environments/atmosphere in any school is important and interrelation of indoor/ outdoor spaces is crucial for the students’ life. The interface of indoor and outdoor spaces in buildings where social interactions and gathering takes place, can be termed or denoted as ‘Courtyard’. The modern and contemporary architecture of educational building consists of elements that are derived of ancient cultural values and built forms. ‘Courtyards’ as being one of these elements which have multifaceted characteristics are becoming the heart of these institutional buildings. Thermal environment of courtyard plays a great role on the quality of an institution. It directly affects people’s behavior and usage of outdoor spaces. Therefore, an environmentally conscious design solution of courtyard should be given high priority to the thermal comfort implications of any institutional buildings. Environmental behavior is an abstract concept resulting from both the human interventions and natural factors operating at different spatial scales. In urban areas the local scale is dominated by individual buildings, streets, trees, courtyards along with their materials and surface treatments. This type of urban developments can be made sustainable by creating sustainable context and by using details that enhance human activities. The aim of this study is to investigate the influence of the built surface along with its material both in the ground and in surrounding wall surface on thermal environment of ‘courtyard’ of three different institutional campuses in the warm humid city of Dhaka. The study is twofold. Firstly, the impact of built surface on the microclimatic conditions was assessed through field measurements and questionnaire survey on thermal sensation in the campus environs of three institutions were conducted to study the subjective response of students to the outdoor thermal environment in a warm humid climate. The field measurements included the monitoring of microclimatic parameters such as air temperature (Ta), relative humidity (RH) and wind speed (v). The influence of various built parameters such as building materials, green cover, etc., on microclimatic conditions and the daytime thermal sensation were assessed. Hand held instruments were used to record climatic data. Secondly finding out the thermal conditions of courtyards during daytime in three institutional campus through computational simulation with Envi-met 3.1. The research shows that courtyards with paved exposed to sun have higher temperature and solar radiation whereas paved area under shade showed lower temperature. Again green areas under shade shows low air temperature than paved area.