Journal of the Korean Solar Energy Society ISSN:1598-6411(Print) 2508-3562(Online) 한국태양에너지학회 논문집

Old buildings over 20 years after completion account for 58.2% of all buildings in Korea. Moreover, buildings built 30 years ago with weak insulation levels have a significant impact on energy consumption in the building sector. Therefore, improving the performance of existing buildings is critical. In addition, green remodeling of old public buildings is currently being implemented in accordance with the mandatory zero-energy construction policy. In Korea, ECO2 based on ISO 13790 and DIN V 18599 is the program used officially to evaluate building energy efficiency ratings and energy independence rates. However, the accuracy of ECO2 is controversial because the cross-use of cooling and heating energy generated in the intermediate stage and the amount of energy used at a specific point in time cannot be analyzed. In addition, previous studies found that the results of a static analysis program showed higher energy performance than those of a dynamic analysis program. In this study, the programs ECO2 and DesignBuilder were used to analyze and compare results of the primary energy consumption (heating, cooling, hot water, lighting, and ventilation) per year for a green-remodeled small public building. Results indicated that the application of the green remodeling elements reduced the primary energy consumption per unit area the most, especially for heating energy. In addition, the change in the building energy efficiency grade through green remodeling improved by two stages from grade 1 to grade 1++ in the case of the ECO2 program, and improved by one stage from grade 1+ to grade 1++ for the DesignBuilder program.