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Influence of ICHTC correlations on the thermal characterization of fa?ades using the quantitative internal infrared thermography method
摘要： The thermal characterization of fa?ades of the existing building stock is essential to establish optimal energy conservation measures. There are different methods to characterize thermal properties of fa?ades. The quantitative internal infrared thermography method is among those most developed. Given the existing differences in the scientific literature among the proposals of the method, this study analysed the influence of the internal convective heat transfer coefficient (ICHTC). In total, 25 correlations of temperature differences (temperature of the wall and internal air temperature) were analysed, as well as 20 correlations of dimensionless numbers. To do this, an experimental campaign was performed in 3 fa?ades belonging to the most representative building periods of the building stock in Spain. First, a cluster analysis was carried out to determine similarities among the equations analysed, using the Ward method as an agglomerative hierarchical method and the Euclidean distance as an association measurement. In total, 12 and 8 groups were obtained for correlations of temperature difference and of dimensionless numbers, respectively. Afterwards, results associated with each approach were obtained. These results showed that a better adjustment was obtained for correlations of dimensionless numbers by using the approach of convection and radiation, with an average value of representative results higher than 80%.
关键词： Fa?ades,Internal convective heat transfer coefficient (ICHTC),U-value,Quantitative internal infrared thermography method
更新于2025-09-23 15:22:29
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Evaluation of Solar Radiation Transposition Models for Passive Energy Management and Building Integrated Photovoltaics
摘要： Incident solar radiation modelling has become of vital importance not only in architectural design considerations, but also in the estimation of the energy production of photovoltaic systems. This is particularly true in the case of buildings with integrated photovoltaics (PV) systems having a wide range of orientations and inclinations defined by the skin of the building. Since solar radiation data at the plane of interest is hardly ever available, this study presents the analysis of two of the most representative transposition models used to obtain the in-plane irradiance using as input data the global and diffuse irradiation on the horizontal plane, which can be obtained by satellite-based models or ground measurements. Both transposition models are validated with experimental measurements taken in Murcia (southeast of Spain) and datasets provided by the photovoltaic geographical information system (PVGIS) and the National Renewable Energy Laboratory (NREL) for vertical surfaces facing the four cardinal points. For the validation, the mean bias deviation, root mean square error and forecasted skill were used as indicators. Results show that the error rate decreases slightly for clear days. Better results are also obtained by dismissing data with low solar elevation angles so as to avoid shadowing effects from the surroundings in the early and late hours of the day, which affects mainly the performance of the transposition models for west and east surfaces. The results highlight the potential of equator-facing fa?ades in winter time when the received irradiation can be twice as much as the one collected by the horizontal plane. It is also noteworthy that the operating conditions of all fa?ades are mainly low irradiance and medium temperature at these locations.
关键词： PV fa?ades,BIPV,anisotropic sky models,solar irradiance
更新于2025-09-19 17:13:59
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Determination of economically optimised building integrated photovoltaic systems for utilisation on facades in the tropical climate: A case study of Colombo, Sri Lanka
摘要： Building integrated photovoltaics (BIPV) are becoming a viable solution for clean on-site energy production and utilisation to combat the existing energy crisis. In tropical climates, although rooftops are ideal for photovoltaic (PV) module integration, the available area may be insufficient to meet building energy demand due to the recent high-rise nature of urban buildings, causing a requirement for the utilisation of facades. However, the high angle of solar elevation means that facades are unfavourably oriented towards receiving incident solar irradiation. In addition, the issue exists of high solar heat gains into built spaces. This paper proposes a method to utilise horizontally inclined photovoltaic modules integrated on solar shading devices in order to combat these issues of unfavourable inclination and solar heat gains in commercial office buildings in Colombo, Sri Lanka. Various strategies are introduced and evaluated in terms of their inclination angles and the distance between installations. The results are analysed in terms of economic potential in order to determine which strategies are capable of producing the most electricity and reducing building cooling loads for the lowest installation costs. The results show that horizontal inclinations of PV on facades are capable of generating nearly 8% more electricity as a percentage of the building energy consumption when compared with traditional vertical PV facade installations.
关键词： facades,office building,photovoltaic integrated shading systems,building integrated photovoltaics,optimisation
更新于2025-09-16 10:30:52