Comparison of Rooftop Surface Temperature and Indoor Temperature for the Evaluation of Cool Roof Performance according to the Rooftop Colors in Summer: Using Thermal Infrared Camera Mounted on UAV

옥상 색상에 따른 쿨루프 성능평가를 위한 여름철 옥상 표면 및 실내온도 비교 분석 : 무인항공기에 장착된 열적외선 카메라를 이용하여

Abstract

The intensity and the number of days of high temperature occurrence are also high and record heat occurred. In addition, the global warming phenomenon is intensifying globally, and especially in South Korea, the urban heat island phenomenon is also occurring due to rapid urbanization due to rapid industrial development. As the temperature of the city rises, it causes problems such as the comfort of the residential living and the cooling load. In this study, the cool roof performance is evaluated according to the roof color to reduce these problems. Unlike previous studies, UAV(Unmanned Aerial Vehicle) thermal infrared camera was used to obtain the surface temperature (white, grey, green, blue, brown, black) according to the rooftop color by remote sensing technique. As a result, the surface temperature of white color was $11{\sim}20^{\circ}C$ lower than other colors. Also air conditioning temperature of white color was $1.5{\sim}4.4^{\circ}C$ lower than other colors and the digital thermometer of white color was about $1.5{\sim}3.5^{\circ}C$ lower than other colors. It was confirmed that the white cool roof performance is the best, and the UAV and the thermal infrared camera can confirm the cool roof performa.

전 세계적으로 지구온난화현상이 심화되고 있으며, 특히 우리나라의 경우 급격한 산업 발전 등으로 인해 도시화가 진행되면서 도시열섬현상까지 발생되고 있다. 이렇게 도시의 온도가 상승하게 되면 주거 생활의 쾌적성 및 냉방부하와 같은 문제 등을 야기한다. 본 연구에서는 이러한 문제를 줄이기 위해 지붕 색상에 따른 쿨루프 성능 평가를 진행하였으며, 기존의 평지붕 축소 모형, 손잡이 형태의 열화상 카메라 또는 레이저 온도계를 이용하지 않고, 실제 건물과 UAV에 열적외선 카메라를 장착하여 원격탐사 기법으로 옥상 색상 (흰색, 회색, 초록색, 청색, 갈색, 검은색)에 따른 표면 온도를 취득하였다. 그 결과 흰색을 적용한 표면 온도가 다른 색상보다 11도에서 20도 낮게 나타났으며, 에어컨의 실내 온도와 디지털 온도계의 실내 온도 또한 흰색의 색상이 다른 색상보다 약 1.5도에서 4.4도, 약 1.5도에서 3.5도 낮게 측정되었다. 이를 통해 흰색이 쿨루프 성능이 가장 좋음을 확인할 수 있었으며, UAV와 열적외선 카메라를 통해 기존 다른 연구에서 사용했던 방법보다 신속하고, 편리하게 쿨루프 성능 평가가 가능함을 확인할 수 있었다.

Fig. 2. Study site drawing (Left of building No. 9)

Fig. 3. Study site : Building No. 9 painting with different colors of Kyungpook National University – Sangju Campus –

Fig. 4. 4th floor of building No. 9 for temperature measurement

Fig. 5. Rooftop surface average temperature acquired by UAV-based thermal infrared camera according to weekly different time (℃)

Fig. 6. Indoor average temperature acquired by the thermometer of the air-conditioning sensor according to weekly different time (℃)

Fig. 7. Indoor average temperature acquired by a thermometer according to the weekly different time (℃)

Fig. 8. Overall average surface and indoor temperature by colors (℃)

Fig. 9. Difference between white and other colors on surface temperature

Fig. 10. Difference between white and other colors on Indoor temperature (Air conditioning thermometer)

Fig. 11. Difference between white and other colors on Indoor temperature (Digital thermometer)

Table 1. Specifications of UAV and thermal infrared camera

Table 3. Rooftop surface temperature images acquired by UAV-based thermal infrared camera according to weekly different time

Table 2. Specifications of air conditioning thermometer and digital thermometer