Energy Performance Evaluation of Electrochromic Windows through Sensitivity Analysis by Control Variables in Residential Buildings

The purpose of this study was to analyze the energy saving performance of Electrochromic window (ECW) by various control variables through sensitivity analysis. To this end, control variables were established as daylight illuminance, solar radiation and indoor air temperature, and then energy performance of ECW applied to residential buildings were evaluated using building energy simualtion tool, EnergyPlus (ver. 9.2.0). In addition, regional trends of Cheorwon (Jungbu1), Seoul (Jungbu2), Busan (Nambu), and Jeju (Jeju), which have different climate condition, were compared. As a result, among the all control variables, the best reduction rate in the sum of cooling and lighting energy consumption was found to be daylight illuminance, which was the same in all regions. In addition, the energy saving effect was in the order of Cheorwon (9.1% to 12.3%) > Jeju (7.1% to 9.5% ) > Seoul (6.1% to 8.7%) > Busan (5.8% to 8.2%). In the case of solar radiation, the lower the interior illuminance, the better the effect, but the best setpoint for tinting were different by region, so it was judged that prior consideration about solar radiation setpoint for tinting is needed when conducting related research in the future. In the case of indoor temperature, the higher the interior illuminance, the greater the energy performance, but the energy consumption saving effect was not significant. ….