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En este trabajo se han evaluado 19 modelos de estimación de irradiancia difusa sobre el plano inclinado, que incluyen tanto modelos isotrópicos o pseudoisotrópicos como modelos anisotrópicos. Dicha evaluación se ha llevado a cabo a partir una serie de 5396 observaciones de irradiancia global, difusa y directa realizadas entre julio y diciembre de 2018 en la estación radiométrica de la Universidad Pública de Navarra (UPNA). El estado del cielo correspondiente a cada observación se ha caracterizado de acuerdo con el CIE Standard General Sky propuesto en la norma ISO 15469:2004(E)/CIE S 011/E:2003. Para esta clasificación se han utilizado las medidas de distribución angular de luminancia y radiancia proporcionadas por un escáner de cielo ubicado en la propia estación de la UPNA. De tal manera que, para cada combinación de orientación e inclinación del plano, se ha evaluado la bondad de los distintos modelos de acuerdo con los 15 tipos de cielo estándar propuestos por la norma ISO/CIE. Los resultados revelan que el modelo de Perez et al. 2 presenta los mejores resultados globales, así como en 5 de los 15 tipos de cielo ISO/CIE., A total of 19 models for estimating diffuse irradiance on the inclined plane have been evaluated in this work, which
include both isotropic or pseudoisotropic models and anisotropic models. This evaluation has been carried out from
a series of 5,396 measurements of global, diffuse and direct irradiance carried out between July and December 2018
at the radiometric station of the Public University of Navarra (UPNA). The sky conditions corresponding to each
observation has been characterized according to the CIE Standard General Sky proposed in the standard ISO
15469:2004(E)/CIE S 011/E:2003. For this classification, the angular distribution of luminance and radiance
measurements provided by a sky scanner located at the UPNA station have been used. In such a way that, for each
combination of plane’s orientation and inclination, the goodness of the different models has been evaluated in
accordance with the 15 standard sky types proposed by the ISO/CIE standard. The results reveal that the Perez et al.
2 model shows the best overall results and for 5 of the 15 ISO/CIE standard sky types, Este trabajo se ha desarrollado en el marco del proyecto IRILURREFLEX (ENE2017-86974-R), financiado por la Agencia Estatal de Investigación (AEI) y el Fondo Europeo de Desarrollo Regional (FEDER).

When assessing the long-term daylight availability or the performance of natural lighting systems in a given location, it is necessary to have representative data of local daylight conditions. The use of a daylight test reference year (TRY) becomes a good option in these cases. This paper proposes and evaluates a procedure for the generation of a typical illuminance year (TIY) considering illuminance as the only variable for selecting the typical periods that make up the reference year. Two versions of TIY are presented, one composed of 12 typical months selected from the series of observations and another composed of 365 typical days. Each of these versions is used to obtain a global illuminance TIY (TGIY) and a diffuse illuminance TIY (TDIY) from a 27-year dataset corresponding to the Vaulx-en-Velin station (France). Furthermore, 12 luminous efficacy models have been evaluated in order to obtain a TIY from a TRY generated from irradiance data when no illuminance data are available. Thus, a global luminous efficacy model and a diffuse model are selected after benchmarking different models, considering both their original coefficients and those adjusted to local conditions. The results reveal that the monthly version of the TGIY and the daily version of the TDIY show the best overall fit to the long-term dataset. TIYs obtained from illuminance data are also observed to be statistically indistinguishable from those obtained after applying a luminous efficacy model to an irradiance-based TRY., This work was performed in the framework of IRILURREFLEX project (ENE2017-86974-R), financed by the Spanish State Research Agency (Agencia Estatal de Investigación, AEI) and the European Regional Development Fund (Fondo Europeo de Desarrollo Regional, FEDER). They thank the Public University of Navarre for awarding Ignacio García Ruiz a Doctoral Fellowship.

A full sky High Dynamic Range imaging system, based on a Single-Lens Reflex camera with a fisheye lens, has been constructed and calibrated with a sky scanner luminance meter. The method considers the geometrical, spectral, timing and orientation issues between instruments. The calibration data sets, having nearly simultaneous measurements under stable sky conditions, were obtained from approximately one month of data using selection variables based in the experimental design. For luminance estimation we use the standard 𝐶𝐼𝐸𝑌 RGB combination and a Spectrally Matched Luminance (𝑆𝑀𝐿) predictor, matching the spectral response of the instruments. With 738 calibration points having luminances up to 23.6 kcd∕m2, covering 98.5% of the sky luminance range, 𝐶𝐼𝐸𝑌 is linearly correlated with sky scanner measurements with a coefficient of determination 𝑅2 = 0.9927 and a Root Mean Squared Error (𝑅𝑀𝑆𝐸) of 7.7%. 𝑆𝑀𝐿 gives better results, with 𝑅2 = 0.9973 and 𝑅𝑀𝑆𝐸 = 5.3%. With 253 calibration points with luminances up to 12.9 kcd∕m2, comprising 94.1% of the sky luminance range, both predictors clearly improve, with 𝑅2 = 0.9964 and 𝑅𝑀𝑆𝐸 = 4.1% in case of 𝐶𝐼𝐸𝑌 and 𝑅2 = 0.9982 and 𝑅𝑀𝑆𝐸 = 2.9% in case of 𝑆𝑀𝐿., This work was performed in the framework of the IRILURREFLEX, Spain project (ENE2017-86974-R), financed by the Spanish State Research Agency (Agencia Estatal de Investigación, AEI) and the European Regional Development Fund (Fondo Europeo de Desarrollo Regional, FEDER).

Mathematical models for the estimation of the angular distribution of diffuse radiance/luminance in the
sky describe the anisotropic character of diffuse solar radiation and daylight in the sky vault. In most of
these models the radiance/luminance of a sky point is determined by the product of the indicatrix
function and the gradation function. When developing and/or calibrating these models, it is typical to
consider separately the dispersion effects in the direction of the sun's rays and the gradation from the
zenith towards the horizon. To do this, the sky is divided into a number of concentric spherical zones
around the sun and a number of concentric spherical zones around the zenith. The intersection between
both sets of zones delimits a series of sky elements. Unfortunately, these sky elements do not correspond
to the 145 patches of sky vault recommended by the International Commission on Illumination (CIE),
which are routinely scanned by the existing commercial sky scanners. The identification of the sky elements, geometrically different from those observed by commercial sky scanners, and the assignation of
the radiance/luminance values registered by such sky scanners are not analytically trivial tasks. A GISbased methodology is presented in this work to undertake these goals., This work was performed in the framework of Project IRILURREFLEX (ENE2017-86974-R), financed by the Spanish State Research Agency (Agencia Estatal de Investigación, AEI) and European Regional Development Fund (Fondo Europeo de Desarrollo Regional, FEDER). They also thank the Public University of Navarre for awarding Ignacio García Ruiz a Doctoral Fellowship.

This work proposes a set of analytical expressions for the calculation of the relationship between sky diffuse illuminance on a tilted plane and horizontal plane corresponding to the 15 ISO/CIE standard sky types. Given the parallelism in the angular distribution of sky diffuse radiance and luminance, these expressions can also be used to calculate the diffuse sky irradiance on an inclined plane. The proposed analytical expressions are obtained by adjusting the results of a numerical calculation whose methodology is described in detail in the paper. The use of these analytical expressions significantly reduces the calculation time. It is verified that the relative root-mean-square errors obtained with the analytical expressions are small compared with the use of numerical calculation, ranging from 0.03% to 4.09%, and with a tendency to increase with clear skies and high solar zenith angles., This work was performed in the framework of IRILURREFLEX project (ENE2017-86974-R), financed by the Spanish State Research Agency (Agencia Estatal de Investigacion, AEI) and the European Regional Development Fund (Fondo Europeo de Desarrollo Regional, FEDER).

Numerous studies have analyzed existing irradiance models for estimating sky diffuse irradiance on tilted planes. However, few have evaluated the suitability of these models for estimating irradiance in obstructed environments, specifically considering the effects of obstacles. In this study, three irradiance models —one of them with five variants— for estimating diffuse irradiance on tilted planes located in urban environments were evaluated. All models have been adapted to consider the effect of an urban canyon on the diffuse irradiance received on a tilted plane through the sky view factor and the circumsolar view factor. All the models were evaluated against the diffuse irradiance values obtained by the ISO 15469:2004(E)/CIE S 011/E:2003 angular distribution model. Therefore, it was necessary to determine the standard sky type corresponding to each record of the measurements performed by a sky scanner at the radiometric station of UPNA (Spain). A total of 4,864 scenarios were considered to occur from the combination of different orientations and inclinations of the plane, and different orientations and aspect ratios of the urban canyon. The results revealed that the Perez model considering a 35° half-angle circumsolar region has the best performance, followed by the Perez model considering a 45° half-angle circumsolar region., This work was performed in the framework of the IRILURREFLEX project (ENE2017-86974-R), financed by the Spanish State Research Agency (Agencia Estatal de Investigación, AEI) and the European Regional Development Fund (Fondo Europeo de Desarrollo Regional, FEDER).

Incluye póster, The characterization of sky conditions according to the CIE Standard General Sky classification requires knowledge of diffuse luminance angular distribution in the sky vault. This variable is usually measured by sky scanners. However, commercial sky scanners have different drawbacks related to their resolution and measurement time. An alternative to these devices is the use of sky images captured with a digital camera equipped with a fisheye lens. The range of luminances that may occur in the sky makes it necessary to use high dynamic range (HDR) images obtained by the fusion of a series of low dynamic range (LDR) images. Two procedures for the characterization of sky conditions according to the CIE standard using HDR images have been applied and evaluated., This work has been performed as a part of Project RECHICRAL (0011-1365-2017-000168), co-financed by the Government of Navarre and the European Regional Development Fund through the FEDER Operational Program 2014-2020 of Navarre, and Project IRILURREFLEX (ENE2017-86974-R), financed by the Spanish State Research Agency (Agencia Estatal de Investigación, AEI) and European Regional Development Fund (Fondo Europeo de Desarrollo Regional, FEDER).

In this article, we compare deterministic methodologies for characterizing channel behavior in heterogeneous and composite scenarios. These techniques include one that combines a 3D ray launching (RL) approach based on geometrical optics (GO), a second based on GO and the uniform theory of diffraction (UTD), and another that includes a diffusion equation (DE) method based on the equation of transfer. A new methodology based on the GO and DE is presented and shown to achieve accurate results when compared with real measurements. The proposed technique provides a computational time reduction of up to 90% compared to the conventional approach using GO with the UTD and DE., This work was funded by the Ministerio de Ciencia, Innovación y Universidades, and Gobierno de España (MCIU/AEI/ FEDER,UE), RTI2018-095499-B-C31.

Since the publication of the standard sky luminance distributions (SSLD) that was consolidated in the ISO 15469:2004(E)/CIE S 011/E:2003, numerous procedures have emerged for the characterization of the sky condition according to that standard. Precisely, the use of different procedures for the classification of the skies of a certain place according to the ISO/CIE standard can lead to obtain different frequencies of sky types. The existing uncertainties in the characterization of the sky condition according to the CIE Standard General Sky as a consequence of the classification procedure used are analyzed in this study. For this, three different classification procedures are used to characterize the sky radiance and luminance distribution measurements made by means of a sky-scanner in Pamplona (Spain) from 2007 to 2013. That is, (1) a method focused on determining the relative gradation and indicatrix functions, (2) a method based on the comparison of measured and standard luminances normalized against the horizontal diffuse illuminance, and (3) a new high-spatial-resolution approach that compares measured and standard luminances relative to zenith. In general terms, it is concluded that there is some uncertainty in the classification depending on the procedure used to characterize the sky., This work was performed in the framework of Project IRILURREFLEX (ENE2017-86974-R), financed by the Spanish State Research Agency (Agencia Estatal de Investigación, AEI) and European Regional Development Fund (Fondo Europeo de Desarrollo Regional, FEDER). The authors would like to thank the Public University of Navarre for awarding Ignacio García Ruiz a Doctoral Fellowship.