The Feasibility of Identifying Defects Illustrated on Building Facades by Applying Thermal Infrared Images with Shadow

Infrared thermography (IRT) has been widely employed to identify the defects illustrated in building facades. However, the IRT covered with a shadow is hard to be applied to determine the defects shown in the IRT. The study proposed an approach based on the multiplicated model to describe quantitively the shadow effects, and the IRT can be segmented into few classes according to the surface temperature information recorded on the IRT by employing a thermal infrared camera. The segmented results were compared with the non-destructive method (acoustic tracing) to verify the correctness and robustness of the approach. From the processed results, the proposed approach did correctly identify the defects illustrated in building facades through the IRTs were covered with shadow.

Download Full-text

Thermal Infrared Images to Identify the Contribution of Surface Materials to the Canopy Layer Heat Island in Hot-Humid Urban Areas

Environmental and Climate Technologies ◽

10.2478/rtuect-2020-0037 ◽

2020 ◽

Vol 24 (1) ◽

pp. 604-623

Author(s):

Floriberta Binarti ◽

Pranowo Pranowo ◽

Soesilo Boedi Leksono

Keyword(s):

Surface Temperature ◽

Infrared Camera ◽

Thermal Infrared ◽

Image Processing Technique ◽

Heat Island ◽

Infrared Images ◽

Canopy Layer ◽

Street Canyons ◽

Thermal Infrared Images ◽

Surface Materials

Abstract This study presents a combination technique of thermal infrared images captured by infrared camera and satellite thermal images retrieved from Landsat-8 OLI TIRS to identify the contribution of vertical and horizontal surface materials in two hot-humid street canyons with similar sky view factor and street orientation. The infrared camera captures surface temperature images of vertical and inclined surfaces of the street canyons. The images at horizontal scale are derived based on six land cover indices – i.e., Land Surface Temperature (LST), surface albedo, thermal emissivity, Normalized Different Vegetation Index (NDVI), Normalized Different Built Area Index (NDBI), Normalized Different Water Index (NDWI) – using an image processing technique conducted in ArcGIS. This study used two micro weather stations to measure microclimate conditions depicting the Canopy Layer Heat Island (CLHI) of the canyons at the same time. Despite the capability of the combined technique to identify the contribution of surface materials to the LST, different radiative and thermal properties of the surface materials insignificantly modified the CLHI.

Download Full-text

Surface Temperature Distribution Characteristics of Marangoni Condensation for Ethanol–Water Mixture Vapor Based on Thermal Infrared Images

Energies ◽

10.3390/en13226057 ◽

2020 ◽

Vol 13 (22) ◽

pp. 6057

Author(s):

Guilong Zhang ◽

Ziqiang Ma ◽

Heng Li ◽

Jinshi Wang

Keyword(s):

Heat Transfer ◽

Temperature Distribution ◽

Surface Temperature ◽

Thermal Infrared ◽

Water Mixture ◽

Distribution Characteristics ◽

Infrared Images ◽

Single Droplet ◽

Surface Temperature Distribution ◽

Thermal Infrared Images

Marangoni condensation is formed due to the surface tension gradient caused by the local temperature or concentration gradient on the condensate surface; thus, the investigation of the surface temperature distribution characteristics is crucial to reveal the condensation mechanism and heat transfer characteristics. Few studies have been conducted on the temperature distribution of the condensate surface. In this study, thermal infrared images were used to measure the temperature distributions of the condensate surface during Marangoni condensation for ethanol–water mixture vapor. The results showed that the surface temperature distribution of the single droplet was uneven, and a large temperature gradient, approximately 15.6 °C/mm, existed at the edge of the condensate droplets. The maximum temperature difference on the droplet surface reached up to 8 °C. During the condensation process, the average surface temperature of a single droplet firstly increased rapidly and then slowly until it approached a certain temperature, whereas that of the condensate surface increased rapidly at the beginning and then changed periodically in a cosine-like curve. The present results will be used to obtain local heat flux and heat transfer coefficients on the condensing surface, and to further establish the relationship between heat transfer and temperature distribution characteristics.

Download Full-text