Ecological Dimension in the Development of the Standard for Energy-Efficient Building Material

This study developed minimum requirements for energy-efficient material of campus building in Yogyakarta based on overall thermal transfer value (OTTV) and daylighting criteria. Measures of energy efficiency are 150-200 lux with minimal 80% for the daylighting distribution and 45 W/m2 for the maximum OTTV. Certain window to wall ratio (WWR) was defined based on the simulation results of the daylighting level and the distribution with considering the feasibility factor. Minimum requirements forthe thermal transmittance (U), the shading coefficient (SC), the solar absorption (a) and the visible light transmittance (VT) were generated from the OTTV calculation of the classroom, which meets the OTTV and the daylighting criteria. The material’sembodied energy was considered in setting several combinations of SC, VT, a and U for each window orientation and typical WWR. The results show that in warm humid areas lower SC and light color surface are more effective in raising energy-efficient building than lower U glazing. Low-U glazing should be avoided since it contains high embodied energy. Defining specific requirements for each window orientation and typical WWR resulted in higher standard value of U, which then offers more possibilities in the design exploration and selecting low embodied energy materials.