Direct Solar Irradiance Research Articles

Sensitivity Analysis of Aerosol Parameter Estimations with Measured Solar Direct and Diffuse Irradiance

Sensitivity analysis of aerosol parameter (refractive index which consists of real and imaginary parts, size distribution which is represented by Junge parameter) estimations with measured solar direct and diffuse irradiance is made. Through experiments with the measured solar direct and diffuse irradiance, it is found that the results from the sensitivity analysis is valid and adequate.

Cacao roasting in rural areas of Peru using concentrated solar thermal energy: experimental results

Solar food processing is gaining interest for income generation. Our solar cacao roaster, designed for rural areas, consists in a horizontal rotating drum, opened at one end to collect solar radiation from Scheffler concentrators of 2.7 or 8 m2 . The experimental results presented bring knowledge on the system's behavior and optimal operation. The influence of the most significant parameters is studied: quantity of cacao, absorptivity of drum's coating, thermal insulation, inclination and rotational speed of the drum. Cacao temperature and direct solar irradiance are monitored to evaluate the performance in roasting time per kilogram of cacao.

Retrieval of precipitable water vapor using MFRSR and comparison with other multisensors over the semi-arid area of northwest China

Precipitable water vapor (PWV) was retrieved using direct solar irradiance at 938nm measured by a multifilter rotating shadowband radiometer (MFRSR) at the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) located in the semi-arid area of northwest China from August 2007 to June 2010. Measurement also occurred at Zhangye, China, at the Atmosphere Radiation Measurements (ARM) Program's Ancillary Facility during the dust period from April to June 2008. The line-by-line radiative transfer model (LBLRTM) code combined with the HITRAN 2004 spectral database is used to model the water vapor spectral transmittance throughout the 938-nm spectral response of MFRSR in the retrieval algorithm. Gaussian fitting is proposed to determine the daily calibration constant at the top of atmosphere for a long-term series under an obvious annual change in solar radiation.PWV retrieved by MFRSR over SACOL shows that 90% of PWV values are smaller than 1.52cm, and PWV distribution has a seasonal variation, with maximum in summer and minimum in winter. The comparisons between MFRSR and other measurements show a better agreement between MFRSR and sunphotometer (AERONET's Cimel) PWV retrievals with relative bias of 2.9% and RMS difference of 9.1% than between MFRSR and microwave radiometer (MWR) with relative bias of 10% and RMS difference of 23% over SACOL, and an excellent agreement between MFRSR and sunphotometer with relative bias of 0.56% and RMS difference of 6.1% over Zhangye.To verify satellite PWV products over the semi-arid area of northwest China, the comparisons of PWV from MODIS and AIRS with MFRSR suggest that the agreement between satellite and MFRSR PWV retrievals is not as good as that between MFRSR and other ground-based instruments. MODIS appears to slightly underestimate PWV in a dry atmosphere but overestimate PWV in a moist atmosphere against MFRSR. A method is proposed to correct MODIS PWV products. AIRS PWV products relative to MFRSR show a systematic underestimation.

Artificial neural network models for predicting the solar radiation as input of a concentrating photovoltaic system

The energy production analysis of a system based on renewable technology depends on the inputs estimation accuracy. The solar energy is a free resource characterized by high variability; hence, its correct evaluation is a strategic factor for the feasibility of a solar system. In this paper a new methodological approach is presented in order to evaluate more accurately the electric and thermal energy production of a point-focus concentrating photovoltaic and thermal system (CPV/T). Two Artificial Neural Network (ANN) models for predicting solar global radiation and direct normal solar irradiance (DNI) are developed adopting different parameters such as climatic, astronomic and radiometric variables. In particular, a new combination of parameters is proposed in this paper and adopted first of all for the global radiation evaluation whose ANN model can be easily compared with the literature; the data are trained and tested by a multi layer perceptron (MLP). Hence, the results validation for the global solar radiation evaluation has encouraged to design an ANN model for the DNI by means of a similar variables set. The MLP network is trained, tested and validated for the hourly DNI estimation obtaining the MAPE, RMSE and R2 statistical indexes values respectively equal to 5.72%, 3.15% and 0.992. Finally, the electric and thermal outputs of a point-focus CPV/T system are evaluated varying the concentration factor and cells number, and adopting as input the DNI evaluation results obtained by the ANN model presented in this paper. The CPV/T system outputs are estimated referring to the city of Salerno (Italy) under different meteorological conditions.

Total ozone column measurements using an ultraviolet multi-filter radiometer

We have developed and used a method to retrieve total ozone column (TOC), from Ultraviolet Multi-filter Rotating Shadowband Radiometer (UVMFR) measurements in combination with radiative transfer model calculations. Look-up tables of ratios of the direct solar irradiance at (DI) 305 and 325nm in terms of TOC, solar zenith angle, and aerosol optical depth (AOD) have been constructed and compared with TOC retrievals estimated directly from UVMFR irradiance measurements. Sensitivity analysis of the influence of AOD on the calculated TOC has been investigated and found to be 1 Dobson unit per 0.1 change in AOD. We also examined the impact of ozone effective temperature on the TOC retrieval and found that it leads to a 0.9% change in TOC per K. UVMFR direct irradiance measurements in Athens, Greece, during the period July 2009–May 2014 were used to create a time series of high-temporal-frequency measurements (1 min for cloudless conditions) of TOC, which facilitated an analysis of the diurnal variation of TOC. Comparison of the TOC retrievals from the UVMFR with co-located and synchronous daily TOC retrievals from a Brewer MKIV spectrophotometer showed very good agreement (correlation coefficient 0.98). Daily TOC retrievals from the UVMFR were within ±3% compared with the ones measured by the Ozone Monitoring Instrument overpasses on board the Aura satellite.

Improved methodology to evaluate clear-sky direct normal irradiance with a multi-pyranometer array

An improved methodology to estimate the clear-sky direct normal irradiance based on an anisotropic clear-sky model using a Multi-Pyranometer Array (MPA) is analyzed in this paper. The MPA is a static platform with four sensors on surfaces at different tilt and azimuth angles, which measured solar irradiance can be used to estimate the normal incident component without the tracking devices that involve more detailed installation and maintenance. The array’s sensors are of the photovoltaic type, which require both the spectral and angle-of-incidence corrections.Based on the general expressions for the solar radiation on each of the MPA sloped surfaces and using a hybrid model that includes an anisotropic sky diffuse component, in this work an improved procedure is presented that estimate the normal direct solar irradiance by grouping two expressions of a couple of MPA sensors and analytically look for a satisfactory solution; one set for the horizontal and south sensors, and another for the east and west sensors. The solution for the east and west sensors is expanded to two new solutions by mirroring their readings according to the solar noon. A final switching scheme based on the expressions denominator size provides the satisfactory direct normal irradiance estimation. The analysis of the results for the analyzed days showed that the root mean square error (RMSE) decreased by around 14–43% in comparison with previous results reported in the literature. The proposed methodology is a promising new approach for MPA.

MUS: A multiscale stochastic model for generating plausible meteorological years designed for multiyear solar energy yield simulations

The inherent variability of the solar resource presents a unique challenge for Concentrating Solar Power (CSP) systems. Incident solar irradiance can fluctuate widely over a short time scale, but plant performance must be assessed for long time periods. In this paper, the concept of Plausible Meteorological Year (PMY) along with the Multiscale Stochastic (MUS) methodology for its synthetic generation is presented. A PMY is herein defined as a high-frequency yearly series of Global Horizontal solar Irradiance (GHI), Direct Normal solar Irradiance (DNI) and other relevant meteorological variables (temperature, relative humidity, and wind speed, among others), which are statistically consistent with the estimated variability of the monthly and annual values of DNI and other variables. An efficient and robust scheme for the generation of a random number of PMYs for a specific location through the combination of various well-established methods is presented and explained. Analyzed data show that, differently from the GHI monthly and annual series which showed to be normally distributed, the DNI series are not normal in all cases analyzed. The concept of PMYs and the associated methodology are presented as a possible solution for the sought goal of stochastic simulation of CSP plants considering the uncertainty and variability inherent to the solar resource. This approach is aimed at the adoption of probabilistic approaches to model variability and uncertainties in both electricity production and system cost to achieve sound estimates of the economic feasibility of commercial CSP plants.

Assessment of a Dual-Channel Array Spectrometer for Ground-Based Ozone Retrievals

AbstractThis study describes a dual-channel array spectrometer system designed to make high-frequency simultaneous spectral global irradiance and direct solar irradiance measurements covering the visible and ultraviolet wavelength ranges. The dual-channel nature of the instrument allows spectrally integrated quantities (e.g., erythema or vitamin D) to be calculated at a rate similar to broadband instruments while retrieving total column ozone (TCO) from the direct solar channel. The characterization and calibration of the instrument is discussed, with emphasis on temperature stabilization (<±0.01°C) and stray light removal. Focusing on the TCO retrieval from direct spectra, results are compared to a collocated Brewer spectrophotometer during the study period of May 2013–January 2014. Agreement for individual measurements made within 20 min of a reference Brewer direct sun observation on relatively clear example days is <1.5%. For all valid individual measurements, the study found an overall bias of 1.1 Dobson units (DU; 0.4%) and scatter of ±6.7 DU (2.2%) for retrievals obtained at airmass values < 4. A dependence on air mass of 6.3 DU (2.0%) per airmass unit is observed and a correlation of R2 = 0.954 is found for all individual measurements, although this is reduced to 0.908 for daily means. TCO retrievals are limited to airmass values < 4 primarily because of residual structure in the transmission spectrum that cannot be attributed to other trace gases. These results are encouraging and suggest that similar instrument designs could make a significant and relatively low-cost contribution to surface measurements of atmospheric radiation.

A new validation protocol for an urban microclimate model based on temperature measurements in a Central European city

In this paper, we provide further evidence of the reliability of a lumped parameter urban canopy model coupled with an EnergyPlus building energy model to estimate urban temperatures. In a previous paper, we presented a preliminary validation of the model using data measured at Masdar Institute, Abu Dhabi, United Arab Emirates. At present, we conduct a more comprehensive validation based on BUBBLE experimental data measured in the Sperrstrasse, a street canyon located in Basel downtown, Switzerland. To extend the coupled scheme for the Sperrstrasse and future work, we developed methods for approximating waste heat releases generated by a heating system, anthropogenic heat gains created by traffic, and direct normal solar irradiance. Based on a baseline coupled scheme model for the Sperrstrasse, we evaluate the sensitivity of urban temperature estimates to ±20% variations of each parameter. We finally show, through Monte-Carlo analysis, that the coupled scheme can achieve satisfactory accuracy in a dense Central European city.

The Impact of the Solar Irradiation, Collector and the Receiver to the Receiver Losses in Parabolic Dish System

Parabolic Dish (PD) is one of Concentrating Solar Power (CSP) technologies that convert sunlight to electricity. PD has shown the highest efficiency by converting nearly 31.25% of solar radiation into electricity and PD has emerged as one of reliable and efficient Renewable Energy (RE) technology. However, the evaluation for the PD system performance by using experimental approach is costly and time consuming. Therefore, a model has become necessary to predict the system performance under several of operating conditions. Nevertheless, current literature on PD modelling is scattered, focusing on individual components and rarely organised in one cohesive report. This paper is to study on the impact of the Direct Solar Irradiance (DNI), collector and receiver to the value of heat transfer to the receiver; solar power intercept by a receiver as well as the receiver loses in 25kW PD system. This study is using a simulation approach and Matlab Simulink was used as the simulation tool. The irradiation data were downloaded from the Meteonorm 7 Software and George Town, Penang in Malaysia has been selected as the location for simulation. Meanwhile, the aluminium and silver was used as the reflective material and the intercepted factor used for the simulation is in the range of 0.9 to 1.0. As a conclussion, the simulation result has shown that variations of the solar irradiation on the site, reflective material and the intercept factors influence the value of the value of the rate of heat transfer to the receiver; solar power intercept by a receiver as well as the receiver loses.

Digging the METEOSAT Treasure—3 Decades of Solar Surface Radiation

Solar surface radiation data of high quality is essential for the appropriate monitoring and analysis of the Earth's radiation budget and the climate system. Further, they are crucial for the efficient planning and operation of solar energy systems. However, well maintained surface measurements are rare in many regions of the world and over the oceans. There, satellite derived information is the exclusive observational source. This emphasizes the important role of satellite based surface radiation data. Within this scope, the new satellite based CM-SAF SARAH (Solar surfAce RAdiation Heliosat) data record is discussed as well as the retrieval method used. The SARAH data are retrieved with the sophisticated SPECMAGIC method, which is based on radiative transfer modeling. The resulting climate data of solar surface irradiance, direct irradiance (horizontal and direct normal) and clear sky irradiance are covering 3 decades. The SARAH data set is validated with surface measurements of the Baseline Surface Radiation Network (BSRN) and of the Global Energy and Balance Archive (GEBA). Comparison with BSRN data is performed in order to estimate the accuracy and precision of the monthly and daily means of solar surface irradiance. The SARAH solar surface irradiance shows a bias of 1.3 \(W/m^2\) and a mean absolute bias (MAB) of 5.5 \(W/m^2\) for monthly means. For direct irradiance the bias and MAB is 1 \(W/m^2\) and 8.2 \(W/m^2\) respectively. Thus, the uncertainty of the SARAH data is in the range of the uncertainty of ground based measurements. In order to evaluate the uncertainty of SARAH based trend analysis the time series of SARAH monthly means are compared to GEBA. It has been found that SARAH enables the analysis of trends with an uncertainty of 1 \(W/m^2/dec\); a remarkable good result for a satellite based climate data record. SARAH has been also compared to its legacy version, the satellite based CM-SAF MVIRI climate data record. Overall, SARAH shows a significant higher accuracy and homogeneity than its legacy version. With its high accuracy and temporal and spatial resolution SARAH is well suited for regional climate monitoring and analysis as well as for solar energy applications.

Assessment of aerosol optical and micro-physical features retrieved from direct and diffuse solar irradiance measurements from Skyradiometer at a high altitude station at Merak: Assessment of aerosol optical features from Merak.

Optical and micro-physical features of aerosol are reported using Skyradiometer (POM-01L, Prede, Japan) observations taken from a high-altitude station Merak, located in north-eastern Ladakh of the western trans-Himalayas region during January 2011 to December 2013. The observed daily mean aerosol optical depth (AOD, at 500 nm) at the site varied from 0.01 to 0.14. However, 75 % of the observed AOD lies below 0.05 during the study period. Seasonal peaks of AOD occurred in spring as 0.06 and minimum in winter as 0.03 which represents the aged background aerosols at the site. Yearly mean AOD at 500 nm is found to be around 0.04 and inter-annual variations of AOD is very small (nearly ±0.01). Angstrom exponent (a) varied seasonally from 0.73 in spring to 1.5 in autumn. About 30 % of the observed a lies below 0.8 which are the indicative for the presence of coarse-mode aerosols at the site. The station exhibits absorbing aerosol features which prominently occurred during spring and that may be attributed by the transported anthropogenic aerosol from Indo-Gangatic Plain (IGP). Results were well substantiated with the air mass back-trajectory analysis. Furthermore, seasonal mean of single scattering albedo (SSA at 500 nm) varied from of 0.94 to 0.98 and a general increasing trend is noticed from 400 to 870 nm wavelengths. These features are apparently regional characteristics of the site. Aerosol asymmetry factor (AS) decreases gradually from 400 to 870 nm and varied from 0.66 to 0.69 at 500 nm across the seasons. Dominance of desert-dust aerosols, associated by coarse mode, is indicated by tri-modal features of aerosol volume size distribution over the station during the entire seasons.

Increasing the Temporal Resolution of Direct Normal Solar Irradiance Series in a Desert Location

Abstract The knowledge of the high-frequency temporal evolution of Direct Normal solar Irradiance (DNI) reaching the ground is a key parameter in the design and operation of Concentrating Solar Thermal Power (CSTP) plants, as instantaneous flickering nature of DNI can affect power system operations in several ways. In this study, a methodology to increase temporal resolution has been applied to increase the frequency of DNI series from 1-hour to 1-minute. This methodology is based in the nondimensionalization of the daily DNI curve by the clear-day envelope approach and uses the solar radiation data obtained in the one-year measurement campaign to characterize the DNI high frequency dynamics at a given site. The evaluation of the method with 2 years of ground measured data in a desert location have resulted in KSI (%) (Kolmogorov–Smirnov test Integral parameter) and normalized root mean square deviation values below 23% and 15% respectively for each month analyzed, with negligible mean bias, demonstrating the accuracy of the methodology.

Thermal Performance of Parabolic Trough Solar Collectors under the Condition of Dramatically Varying DNI

Abstract Frequently interrupted by dense clouds during the operational period, the thermal performance of parabolic trough solar collectors will experience considerable variations. Therefore, both theoretical and experiment studies were developed to analyze the dynamic thermal performance under the condition of dramatically varying direct normal solar irradiance (DNI) based on energy balance equations and a thermodynamics analysis. Particularly for a closed system, this unfavorable weather condition leads to the variation in the outlet temperature of parabolic trough solar collectors. Consequently, both of main factors which impact on the running status of the whole system are coupled to make heat transfer processes complex. In order to eliminate important errors due to fluctuations of the outlet temperature and DNI, the differential control volume methodology was used to model the solar irradiance in each volume based on the time intervals of the data acquisition system.

Study on the Performance of the Solar Cooling System Using Cavity Receiver Based on the Neural Network

A solar absorption cooling system with cavity receiverfor demonstration was introduced. The system consisted of a double-effectlithium bromide chiller and a parabolic trough concentrator with cavitysolar receiver.The high temperature heat from the cavity receiver enabled the chiller to operate in double-effect state,and the refrigerant water produced by the refrigerator flowed through the end fan coil toadjust the room temperature.Monitoring data from the demonstration system showed that instantaneous efficiency of the solar cavity receiverwas about 44%in direct solar irradiance of about 500W/m2, the receiver outlet temperature was150oC and thetemperature difference between the receiver outlet and the receiverinlet was 10oC.The lithium bromide refrigerator operated in the state of double effect in good solar irradiation, the refrigeration efficiency was about 1.2, and chilled watertemperature in the storage tank was about 15oC, and the room temperature was maintained at about 25oC. The experimental results showed that the design system could meet the demand of refrigeration and it was verified that the cavity receiver used in double-effect lithium bromide absorption refrigeration scheme was suitable.The relationships between the heat gain, inlet temperature, outlet temperature and flow rate of the working medium in the solar cavity receiver were analyzed, and the main influence factors on the heat gain of the solar cavity receiver were determined. On this basis, acavity receiver heat gain prediction model was establishedbased on a RBF neural network.The simulation results showed that the model predicted values and the measured values had good consistency,so the RBF neural network model could accurately predict the temperature rise of working medium of the solar cavity receiver.

Minute resolution estimates of the diffuse fraction of global irradiance for southeastern Australia

Separating global horizontal irradiance measurements into direct and diffuse components has been vigorously discussed over the past half-century of solar radiation research leading to the creation of many models which attempt to compute these components with varying degrees of success. However, over the course of this discussion, nearly all studies have focused on hourly values, with no studies that have proposed a model for minute-level values of irradiance. As data-logging technologies have become much more prolific and their storage capabilities much larger, solar radiation monitoring sites are more commonly logging data at intervals much less than one hour, but no models exists that are designed to separate these measurements into direct and diffuse components. In Australia, the Australian Bureau of Meteorology and the Australian Solar Institute have compiled a dataset of tens of millions of one-minute global, direct and diffuse solar irradiance observations, comprising data from regions all around Australia. This dataset provides a unique opportunity to investigate the relationships between global irradiance and its direct and diffuse components at higher resolution than has previously been possible. Herein, the largest and most complete diffuse fraction model analysis yet undertaken for Australian solar radiation data, and the first ever to focus on minute resolution data is reported. Nine of the most prominent diffuse fraction, or “separation”, models are tested against minute resolution radiation data from three datasets. The first removed cloud enhancement events in accordance with practices undertaken by the majority of studies in the literature. The second retains these events in order to assess which model would be best suited for operational purposes. The third consisted of only clear sky observations, in order to assess the performance of diffuse fraction models under clear skies. Through the course of this study only the Perez model was found to perform satisfactorily for minute resolution data at sites in southeastern Australia. Three new diffuse models proposed in this study, one trained for each of the three datasets, were found to greatly exceed the performance of existing modeling techniques, with slight improvements over the Perez model.

Comparison of solar radiation models and their validation under Algerian climate – The case of direct irradiance

The accurate prediction of direct solar irradiance is essential in many solar energy applications, particularly those relying on concentrating solar technologies. The present paper is aimed at a detailed assessment of a large range of clear-sky solar radiation models under Algerian climate to select the more accurate one for estimating the performance of solar power projects where meteorological and radiometric measurement stations are not available. To this end, seventeen models have been reviewed and their performance compared to measured irradiance of Ghardaia (Southern Algeria). The validation methodology presented herein is very helpful for ranking the models. A new statistical accuracy indicator has been originally introduced to find out the most accurate ones.A thorough analysis of selected models has shown that the more complex models, that seem at first sight more sophisticated, are not necessary the most accurate; while simpler models depending on a limited number of parameters are more suitable. In other words, the suitability and accuracy of a model do not necessarily improve with an increase in the number of its parameters. This important finding is in good agreement with the previous published studies. This fact is important to take into account, in the case where measured data are not available, for the selection of the most suitable locations for the installation of the future concentrating solar power plants in Algeria or even in other countries.

A method to measure the broadband longwave irradiance in the terrestrial direct solar beam

Shortwave radiometers such as pyranometers, pyrheliometers, photovoltaic cells, and longwave radiometers such as pyrgeometers are calibrated with traceability to consensus References, which are maintained by Absolute Cavity Radiometers (ACRs) and the World InfraRed Standard Group (WISG), respectively. Since the ACR is an open cavity with no window, and was developed to measure the extended broadband spectrum of the terrestrial direct solar beam irradiance, then there would be discrepancy in calibrating the shortwave radiometers because of their limited spectral band. On the other hand, pyrgeometers are calibrated during the nighttime only, because no consensus reference has yet been established for the daytime longwave irradiance. This article describes a method to measure the broadband longwave irradiance in the terrestrial direct solar beam from 3µm to 50µm. The method might be used in developing calibration methods to address the mismatch between the broadband ACR and shortwave radiometers, and the lack of a daytime reference for pyrgeometer calibration. We used the described method to measure the irradiance from sunrise to sunset; the irradiance varied from approximately 1Wm−2 to 16Wm−2 with an estimated uncertainty of 1.46Wm−2, for a solar zenith angle range from 80° to 16°, respectively.

Increasing the temporal resolution of direct normal solar irradiance series in different climatic zones

A precise knowledge of the high-frequency variation of the incoming Direct Normal solar Irradiance (DNI) is required for an accurate design and operation of Concentrating Solar Thermal Power (CSTP) plants. The time resolution of the numerical weather prediction models or satellite derived solar irradiance data are typically limited to 1-h (at best 15-min). Unfortunately, this resolution is not sufficient in the design and performance of a CSTP plant, which shows a nonlinear response to DNI governed by various thermal inertias due to their complex response characteristics. In this study, a new methodology has been developed to increase the temporal resolution of DNI series from 1-h to 1-min. This methodology is based upon the nondimensionalization of the daily DNI curve by the clear-sky envelope approach and uses the solar radiation data obtained in the one-year measurement campaign to characterize the DNI high-frequency dynamics at a given site. The evaluation of the method with 2years of measured data in different climatic zones has resulted in KSI(%) (Kolmogorov–Smirnov test Integral parameter) and normalized root mean square deviation values below 23% and 22% respectively for each month, with negligible bias. Indicators of overall performance show an excellent agreement between measured and modeled 1-min DNI data for each month: average values for Nash–Sutcliffe efficiency, Willmott index of agreement and Legates coefficient of efficiency are found to be 0.90, 0.97 and 1.0, respectively.

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

. 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.Résumé. Les ombres projetées par les grands arbres et les bâtiments dans les zones urbaines peuvent considérablement réduire le rayonnement solaire direct atteignant la surface des bâtiments. La modélisation 3D précise et détaillée des bâtiments et des arbres a été un défi majeur dans l'évaluation du potentiel de l'énergie solaire au niveau du bâtiment. Cette étude présente une nouvelle approche pour l'évaluation du potentiel de l'énergie solaire à l'échelle du bâtiment en intégrant la télédétection et l'analyse 3D. L'éclairement normal direct horaire a été estimé à partir d'observations par satellites météorologiques. Les bâtiments et les arbres ont été modélisés en 3D à l'aide de données de nuages de points de détection et télémétrie par ondes lumineuses « Light Detection and Ranging » (LiDAR) et d'images QuickBird. Les ombres ont été simulées à l'aide d'une méthode de raycasting vectoriel et leurs surfaces ont été calculées en utilisant une méthode modifiée du principe d'inclusion-exclusion. L'énergie directe accumulée a été calculée en intégrant dans le temps l'éclairement solaire direct reçu par les surfaces des bâtiments. Pour réaliser une étude de cas, l'approche proposée a été appliquée pour évaluer le potentiel de l'énergie solaire dans une communauté de bâtiments dans la ville de Nanjing, Jiangsu, en Chine. Les résultats montrent que l'approche est très prometteuse et permet d'offrir des informations détaillées et utiles sur la répartition du rayonnement solaire local sur les bâtiments.