THE INFLUENCE OF WWR AND SHADING DESIGN TO OTTV VALUE IN COWORKING SPACE YOGYAKARTA

Abstract

ABSTRACT: The increasing trend of Work From Cafe (WFC) in urban areas has amplified the demand for comfortable indoor environments in commercial buildings like cafes and coworking spaces. However, many such spaces face overheating issues, compromising user comfort and efficiency. One key factor is the high Overall Thermal Transfer Value (OTTV) caused by large openings on east and west-facing walls without proper shading. This study analyzes the Eplus.Co Coffee & Co-working space in Yogyakarta to assess its OTTV performance. Using ASHRAE 90.1 standards, a maximum Window-to-Wall Ratio (WWR) of 40% was calculated for each side, while the OTTV was measured against the SNI 03- 6389-2011 standard, with a maximum allowable value of 35 W/m². The analysis revealed that the building's WWR exceeds 40% on all sides, leading to OTTV values surpassing the standard, especially on the east (56.42 W/m²) and west (51.09 W/m²) walls. To address this, recommendations were made by studying shading designs. Horizontal shading was found to effectively reduce the OTTV, achieving a compliant value of 34.22 W/m². This research highlights the importance of proper shading and envelope design to enhance thermal comfort and energy efficiency in commercial buildings.