Energy-Efficient Design of Building Envelopes for Multi-Story Buildings in Tropical Climates

Abstract

The building envelope is essential in controlling heat exchange and maintaining thermal comfort within indoor spaces, particularly in multi-story buildings with extensive glass surfaces. This study investigates the thermal performance of building envelopes in a humid tropical climate, using the Overall Thermal Transfer Value (OTTV) as a quantitative measure of energy efficiency. Focusing on the west façade of the Library Building at Universitas Sebelas Maret, the research identifies an OTTV of 61.65 W/m², attributed to the extensive use of untreated glass. This condition results in a high thermal load and increased cooling energy demands. The study also explores the effectiveness of integrating greenery systems on wall surfaces, which achieved a maximum surface temperature reduction of up to 20%. However, this strategy proved to be insufficient if not applied uniformly across all façade orientations. The findings emphasize that minimizing glass proportions and incorporating green elements can significantly reduce thermal loads, particularly on the west side. The study concludes with a recommendation to optimize envelope design and utilize eco-friendly materials to enhance energy efficiency in multi-story buildings located in tropical climates.