Samuel Getachew Bulti^1,, Nebyou Yonas Gabore²

The office building thermal comfort is very important for occupant performance. This study investigates the thermal comfort performance of the naturally ventilated buildings of five selected Addis Ababa sub-city administration offices in different orientations. The objective of the study is to evaluate and compare the office building thermal performance in different orientations with the same thermal insulation materials. This research study is based on building users survey, field measurements, and secondary data review and analysis. The field study and survey were carried in the warmest month of the city May 2019 for a selected room of the case buildings. The field study and survey assessed the indoor air temperatures and relative humidity levels of selected five office building rooms, as the occupants completed questionnaires covering their thermal sensations and thermal preferences. The data obtained from the survey was analysed by SPSS and excel software and secondary data was analysed in a practical part through measurement from survey data collection. Results of field studies have shown that most of the occupants prefer a cooler environment and found their thermal environment not comfortable. The indoor temperature fluctuation of the buildings and the humidity level are within the allowable limits. But, sometimes the temperature levels overpass the acceptable range. The result also revealed that there is a difference in thermal performance between the buildings in different orientations. At the time of measurements building ‘III’ oriented towards North West perform better to occupants thermal environment compared to other buildings. Consequently, to improve the internal environment, additional appropriate passive design strategies are recommended.

thermal performance, thermal comfort, natural ventilation, passive design