Experimental study on the thermal performance of thermally activated internal louvers

Abstract

Shading devices are commonly used to regulate building energy consumption, with internal shading devices being particularly effective in enabling occupants to control indoor thermal conditions and enhance comfort. This study proposes a thermally activated internal louver (TAIL) that integrates water pipes with Venetian louvers as an internal shading device. The effects of the TAIL on indoor thermal conditions and cooling energy consumption were experimentally analyzed during the cooling season in Busan, South Korea, which is characterized by hot and humid summers. Six experimental cases were established based on TAIL activation and louver angles. A solar simulator was used to represent indoor summer solar radiation. The results demonstrated that TAIL activation reduced the air and operative temperatures in the perimeter zone and minimized the temperature differences between the perimeter and interior zones as the louver angle increased. The predicted mean vote (PMV) decreased by up to 0.72, indicating improved thermal comfort. The vertical air temperature differences increased with the TAIL activation and decreased as the louver angle increased. In terms of the cooling performance, the TAIL increased the total cooling capacity while reducing the on-time ratio, facilitating faster heat removal. In addition, TAIL operation enhanced chiller efficiency by increasing system ΔT by 0.94–1.15 °C, reducing energy consumption by up to 14.5 %. These findings confirm that the TAIL improves the perimeter-zone thermal environment, promotes uniform indoor temperatures, and enhances energy efficiency. This study provides insights into the operational feasibility of thermally activated internal louvers for the thermal regulation of indoor spaces.