Façade design modification in complying the Indonesia’s national standard of energy conservation for tall building envelope – Case study: Green Office Park 9, Serpong, Indonesia

Most tall buildings use glass as its façade and exterior materials, which makes the building's envelope is exposed to heat penetration. It important select design proportion between transparent opaque materials for building reduce gain from outside, strategic conserve energy buildings. This study aimed observe of in accordance with effort order AC system. The modification calculated by using Overall Thermal Transfer Value (OTTV) method compliance Indonesia's National Standard Energy Conservation Tall Buildings. results show that on can improve thermal performance building. There a dramatic change OTTV 124.40 w/m2 original 27.73 after several steps modification. biggest reductions obtained when modifications openings are applied. Since transmission mainly coming into through openings, windows keys. material, clear-glass those lower shading coefficient (SC) gives reduction 37.52 w/m2.