研究目的
To analyze the influence of internal convective heat transfer coefficient (ICHTC) correlations on the thermal characterization of fa?ades using the quantitative internal infrared thermography method.
研究成果
The study concludes that correlations of dimensionless numbers using the convection-radiation approach provide the most accurate results for thermal transmittance measurement, with over 80% representative results. This method is efficient for energy audits in existing buildings, offering quick and non-destructive assessment. Future work should extend to light walls.
研究不足
The study is limited to specific wall types (double leaf brick walls with air gap) in a particular climate zone (Csa in Seville). It does not address light walls or other building materials. The experimental conditions require specific environmental controls (e.g., low wind speed, no rainfall), which may not be feasible in all settings. The cluster analysis and results are based on a finite set of correlations and may not cover all possible ICHTC equations.
1：Experimental Design and Method Selection:
The study used the quantitative internal infrared thermography method to analyze ICHTC correlations. A cluster analysis was performed using the Ward method and Euclidean distance to group similar equations. Two approaches were used: convection-only and convection-radiation.
2：Sample Selection and Data Sources:
Three fa?ades from different building periods in Spain (Wall A, B, C) were monitored. They were double leaf brick walls with or without insulation, facing north, and in good conservation state without moisture.
3：List of Experimental Equipment and Materials:
Infrared camera FLIR E60bx, thermocouples T 190-2, re?ector foil, black body tape, heat ?ux plate FQA018C, and software FLIR Tools+ and RStudio.
4：Experimental Procedures and Operational Workflow:
Tests were conducted in winter with temperature differences between 10-15°C, wind speed <1 m/s, no rainfall. Infrared camera placed 1.5m from wall at 20° angle; thermocouples at 1.5m height, 20cm from wall. Emissivity measured with black body tape. Each test lasted 2.5 hours with data acquisition every 15 seconds; 4 tests per wall.
5：5m from wall at 20° angle; thermocouples at 5m height, 20cm from wall. Emissivity measured with black body tape. Each test lasted 5 hours with data acquisition every 15 seconds; 4 tests per wall.
Data Analysis Methods:
5. Data Analysis Methods: Cluster analysis to group ICHTC correlations. Thermal transmittance (U-value) calculated and compared to reference values from ISO 6946 and ISO 9869-1. Uncertainty estimated using combined standard uncertainty.
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