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

Recently, smart window be focused on attention with improvement of occupants comfort and building energy performance. Among various smart window, electrochromic glazing (ECG) has outperformed response and can real-time control. In past year, energy simulation and field test of ECG are conducted with various region and building types using control parameters. However, few studies have been performed with design position of ECG in building. This paper analyzed thermal and optical characteristics with ECG position in double layered clear glazing and low-e glazing. It also performed building energy simulation for typical medium office building with different design position of ECG in summer and winter season. First, U-value of ECG+low-e glazing set was higher thermal performance than ECG+clear glazing set. It is more advantageous to position the ECG on the outside than inside position to prevent solar radiation when changed from clear to tint state of ECG. Also, external positioned ECG can contribute to the reduction transmitted solar radiation at clear state of ECG in double clear glazing set. However, internal positioned cleared ECG was more effective to prevent solar radiation in double low-e glazing set because low-e glazing has lower solar transmittance and higher front surface reflectance. The solar transmittance characteristics was compared with different positioned ECG in summer and winter season for typical medium office building. In summer season, external ECG (tint state)+clear/low-e glazing set was more advantageous to prevent transmitted solar radiation by 93% than double layered clear glazing in Incheon, Korea. The ECG+clear glazing set can increase solar radiation compared to ECG+low-e glazing in winter season. Especially, combination of clear glazing+internal ECG outperformed to save heating load than other cases and showed little difference as the amount of transmitted solar radiation was less 10% than double layered clear glazing set for winter season. Finally, ECG+low-e combination can also reduce cooling and heating system sizing by 28%, 26% in approximation with different state of ECG.