BUILDING ENVELOPE OPTIMIZATION IN INDONESIAN MEDIUM OFFICE FOR ENERGY CONSUMPTION, THERMAL COMFORT, AND DAYLIGHTING PERFORMANCE

• Main Author: Ichwania, Chalila
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/69874
• Institution: Institut Teknologi Bandung

Improving building performance potentially resulting in a positive impact on the environment and energy consumption in the building sectors. Indonesia issued a national standard for building energy conservation known SNI 6389:2011 where this standard serves as a guideline for building practitioners in designing energy efficient buildings in Indonesia. One aspect that regulated in this standard is the value of Overall Thermal Transfer Value (OTTV) that recommended to be met in the building design stage. In addition, PERGUB Jakarta No. 38/2012 on guidelines green buildings also provides reference values for building envelope parameters to meet the regulated OTTV values and the potential energy savings that can be obtained by maximizing the design of the building envelopes. PERGUB Jakarta No. 38/2012, also shows that office buildings have the greatest savings potential compared to other building types. According to the 2019 Energy Conservation Technology Center (B2PTKE) survey on commercial buildings in Indonesia, large-sized office buildings have a lower average energy consumption compared to medium-sized office buildings. This shows that medium-sized office buildings have worse energy consumption performance compared to large-sized office buildings. Despite some regulations and standards have been issued to help building designer in designing energy efficient buildings, these references have not considered other building performance aspect such as occupant thermal comfort and daylight availability. The presence of a guideline or a reference that also consider this aspect could become an alternative of reference for building designer to produce energy efficient building designs without compromising occupant comfort and needs. Based on that situation, this study, aims to conduct an optimization of the building envelope design of medium-sized office buildings to produce optimal designs in respect of energy consumption, thermal comfort, and daylight avaliability in tropical, especially in Indonesia. The building performance metric used in this study are the Energy Consumption Intensity (EUI), Percentage Comfort Hour (PCH) to represent occupant thermal comfort which calculated based on adaptive thermal comfort approach, and Spatial Daylight Autonomy (sDA300/50%) and Annual Sunlight Exposure (ASE1000,250) which represent daylight availability. Building envelope parameters that are observed in this study including: brick thickness, brick conductivity, room height, window U-value, Solar Heat Gain Coefficient (SHGC), glass transmission, Window to Wall Ratio (WWR), building orientation, overhang width, infiltration rate, and window height. The process of generating optimal design samples was carried out using grasshopper plug in called Octopus based on the Strength Pareto Evolutionary Algorithm (SPEA-2) and Hypervolume Estimation Algorithm (HypE). In addition, Octopus is used to produce design combinations toward the optimal value. The optimum design decisions are made based on the Weighted Sum method and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). From the optimum design results, the top 20 design solutions of each method were further tested to see the robustness of design solutions in respect to each decision-making method. Optimization of building envelope parameters resulted in 1069 alternative solutions. Decision-making using the Weighted Sum and TOPSIS methods resulting in the same optimal design combination. Therefore, this combination of designs was decided as the optimal solution. The optimal solution has an EUI performance compared to the proposed office model, as well as 6.9% improvement in PCH, and 200% improvement in sDA300/50% compared to the baseline model. Meanwhile, the improvement on ASE1000,250 in rather insignificant but still below the allowable of value. In addition, 20 alternative solution recommendations from each decision-making method are also reported in this study which can be used as a reference in designing office buildings. Furthermore, sensitivity analysis and robustness analysis were carried out on building envelope variables. Sensitivity analysis shows that WWR variables are variables that require more attention because they have a significant effect on the observed performance indicators. Meanwhile, the results of robustness analysis, show that the Weighted Sum method is not as diverse as the TOPSIS method.