Journal of Korean Institute of Architectural Sustainable Environment and Building Systems ISSN:1976-6483(Print) 2586-0666(Online) 한국건축친환경설비학회논문집

This study summarized and analyzed the operation status of heating, ventilation, and air conditioning (HVAC) in buildings using the data acquired by a building energy management system (BEMS) and identified the operation performance. The target building was a library where energy efficiency grade, passive buildings, and passive and active elements were applied such as Grade 5 zero energy building (ZEB). The main components of the HVAC system was composed of thermal storage tank system utilizing the mid-night electric power and geothermal heat pump. The analysis results verified that the mean Coefficient of Performances (COP) of the heat pump device and the system during heating operation were 3.7 and 3.2, which were decreased in operating efficiency by -2.9% and -4.5%, and 4.5 and 3.4 during cooling operation, which were improved in operating efficiency by 5.7% and -5.0%. In the middle of the process that checked the loss of heat storage during cooling operation, the design errors occurred in the pipe system in the thermal storage tank were verified. The temperature stratification inside the thermal storage system was not made because the 3-way valve was not implemented in the sections of the heat pump and thermal storage tank. The comparison results based on the assumption of normal design showed that the heat storage loss for 22 days in a month of July in 2019 was 31,228 kWh. Considering the daily loss and system COP, the entire power loss of heat storage in July was 9,281 kWh, which incurred additional cost of KRW 514,161 accordingly.