The Effect of Inlet-Outlet Position and Ratio on Airflow Patterns and Privacy in Low-Cost Flat Units in Surabaya

A low-cost rental flat is a vertical building with natural ventilation as the primary
ventilation source for its units. In practice, residents do not use room openings optimally because it tends to reduce room privacy. The consideration of the position and inlet-outlet area ratio is essential to create better privacy with airflow patterns that support room
activities. The research consists of two stages. The first stage was carried out using qualitative methods, which proved the utilization of openings in the hallway side influenced user privacy. This paper discusses the results of the second stage, which was carried out using quantitative methods. The research aims to solve low-cost flats cross-ventilation problem. Data collection using quantitative methods based on observations, data analysis using simulations of airflow patterns, and distribution analysis tables. The results show that the airflow pattern in the existing design does not support the residents activities with the applied room openings having poor privacy. The proposed designs with privacy parameters
consideration, an opening area ratio of 1 (inlet): 1.6 (outlet) and a ratio of 1 (inlet):2 (outlet) shows an average increase of 50% in airflow velocity and privacy in the unit room compared to the existing design.