An Integrative Approach for Solar Energy Potential Estimation Through 3D Modeling of Buildings and Trees

Abstract. Shadows cast by tall trees and buildings in urban areas can dramatically reduce the direct solar radiation reaching building surfaces. Accurate and detailed 3D modeling of buildings and trees has been a major challenge in the assessment of solar energy potential at building level. This study presents a new approach for the assessment of solar energy potential at the building scale by integrating remote sensing and 3D analysis. The hourly direct normal irradiance was estimated from meteorological satellite observation. The buildings and trees in 3D were modeled based on Light Detection and Ranging (LiDAR) point cloud data and QuickBird imagery. Shadows were simulated using a vector-based ray casting method, and their areas were calculated using a method modified from the Inclusion-Exclusion principle. The accumulated direct energy was integrated with the direct solar irradiance received by building surfaces over time. The proposed approach has been applied to assess the solar energy potential in a building community in the City of Nanjing, Jiangsu, China as a case study. The results show that the approach is highly promising and capable of offering detailed and valuable information on the distribution of local solar radiation on buildings. Resume. Les ombres projetees parles grands arbres et les batiments dans les zones urbaines peuvent considerablement reduire le rayonnement solaire direct atteignant la surface des batiments. La modelisation 3D precise et detaillee des batiments et des arbres a ete un defi majeur dans l'evaluation du potentiel de l'energie solaire au niveau du batiment. Cette etude presente une nouvelle approche pour l'evaluation du potentiel de l'energie solaire a l'echelle du batiment en integrant la teledetection et l'analyse 3D. L'eclairement normal direct horaire a ete estime a partir d'observations par satellites meteorologiques. Les batiments et les arbres ont ete modelises en 3D a l'aide de donnees de nuages de points de detection et telemetrie par ondes lumineuses << Light Detection and Ranging >> (LiDAR) et d'images QuickBird. Les ombres ont ete simulees a l'aide d'une methode de raycasting vectoriel et leurs surfaces ont ete calculees en utilisant une methode modifiee du principe d'inclusion-exclusion. L'energie directe accumulee a ete calculee en integrant dans le temps l'eclairement solaire direct recu par les surfaces des batiments. Pour realiser une etude de cas, l'approche proposee a ete appliquee pour evaluer le potentiel de l'energie solaire dans une communaute de batiments dans la ville de Nanjing, Jiangsu, en Chine. Les resultats montrent que l'approche est tres prometteuse et permet d'offrir des informations detaillees et utiles sur la repartition du rayonnement solaire local sur les batiments.Ministry of Science and Technology (MOST), China; [2012BAH27B03]; [2012BAH27B02]; [2013GXS3B048]SCI(E)CPCI-S(ISTP)2,SI126-1344