http://documenta.ciemat.es/handle/123456789/7 2026-03-10T21:56:54Z 2026-03-10T21:56:54Z Polo, J. Martín-Pomares, L. Gueymard, C.A. Balenzategui, J.L. Fabero, F. Silva, J.P. http://documenta.ciemat.es/handle/123456789/5797 2026-02-19T05:48:35Z 2019-01-01T00:00:00Z

Title: Chapter 1 Fundamentals: Quantities, Definitions, and Units en Solar Resources Mapping Authors: Polo, J.; Martín-Pomares, L.; Gueymard, C.A.; Balenzategui, J.L.; Fabero, F.; Silva, J.P. Abstract: Solar radiation is a generic term that refers to different magnitudes of the solar electromagnetic radiation. The quantification of solar radiation incident at the Earth’s surface is of high interest in many disciplines (radiative transfer in the atmosphere, meteorology and climatology, remote sensing of the atmosphere, solar energy studies, etc.). This multidisciplinary aspect of solar radiation sometimes produces duplication of names, definitions, or units. Moreover, different application-specific conventions for variable naming or units exist, which can be confusing. The solar irradiance that reaches a point at the Earth’s surface is basically dominated by (i) the geometric aspects of the Earth’s orbit around the Sun, and the inclination of its rotation axis in the ecliptic plane that determines the incident angle of the Sun rays; and (ii) the interaction mechanisms of solar radiation with various types of atmospheric constituents. This chapter intends to give the reader an overview of the basic definitions of the main variables that are commonly found in solar energy, and hence in this book as well. In addition, some basic aspects of solar geometry are briefly presented, followed by a concise description of the fundamentals of radiation-transfer modeling in the atmosphere. Detailed information on these topics, which is out of the scope of this book, can be found in many textbooks and the abundant literature on solar radiation, radiative transfer and atmospheric physics, to which the avid reader is referred for additional insight

2019-01-01T00:00:00Z Gandía, J.J. Cárabe, J. Fabero, F. Jiménez, R. Rivero, J.M. http://documenta.ciemat.es/handle/123456789/5796 2026-02-19T05:48:27Z 2001-01-01T00:00:00Z

Title: A NEW PROCEDURE FOR THE ACCURATE INDOOR MEASUREMENT OF SOLAR-CELL I-V CHARACTERISTICS Authors: Gandía, J.J.; Cárabe, J.; Fabero, F.; Jiménez, R.; Rivero, J.M. Abstract: The present work describes and validates a method for the adjustment of light intensity in indoor solar-cell I-V tests. The procedure basically consists of the evaluation of the spectral-mismatch parameter as a function of light intensity before measuring. The simulator is set to the irradiance that produces a spectral-mismatch parameter equal to unity (or to some other desired value) and only then is the I-V curve taken. The main advantages are: no need to use very similar reference and test cells, direct extraction of the right whole I-V curve without cell models and ease to measure under different light intensities.

2001-01-01T00:00:00Z Balenzategui, J.L. De Lucas, J. Cuenca, J. González-Leitón, A. Molero, M. Fabero, F. Silva, J.P. Mejuto, E. Muñoz, R. Arce, A. http://documenta.ciemat.es/handle/123456789/5795 2026-02-19T05:48:20Z 2022-01-01T00:00:00Z

Title: Characterization of absolute cavity radiometers for traceability to SI of solar irradiance Authors: Balenzategui, J.L.; De Lucas, J.; Cuenca, J.; González-Leitón, A.; Molero, M.; Fabero, F.; Silva, J.P.; Mejuto, E.; Muñoz, R.; Arce, A. Abstract: Solar-type cavity radiometers are instruments of the highest metrological level for measuring solar direct normal irradiance. To ensure their traceability and performance, they are periodically compared to the World Group of Standards, which realizes the World Radiometric Reference (WRR), in the International Pyrheliometer Comparisons (IPCs). Additionally, they can be characterized in an absolute way, with direct traceability to SI units and with their measurement uncertainty calculated. This paper describes the different techniques and procedures applied for the characterization and calibration of solar cavity radiometers, with the main results obtained to date in the case of an Automatic Hickey–Frieden (AHF) radiometer. Voltmeters, resistors, temperature sensors and the area of the precision apertures have been calibrated, while the effective absorptance, temperature coefficients, optical scattering and non-equivalence factor have been evaluated. The temperature dependence of the electrical current in the cavity heater has also been analysed. The resulting corrections obtained for the AHF by characterization are compatible with the WRR factors obtained by this instrument in the past IPCs. An uncertainty of 0.42% (k = 1) has been obtained, and this paper discusses further improvements that may be able to reduce this figure to the desired expanded uncertainty of U = 0.1% (k = 2).

2022-01-01T00:00:00Z Balenzategui, J.L. Molero, M. Silva, J.P. Fabero, F. Cuenca, J. Mejuto, E. De Lucas, J. http://documenta.ciemat.es/handle/123456789/5794 2026-02-19T05:48:13Z 2022-01-01T00:00:00Z

Title: Uncertainty in the Calibration Transfer of Solar Irradiance Scale: From Absolute Cavity Radiometers to Standard Pyrheliometers Authors: Balenzategui, J.L.; Molero, M.; Silva, J.P.; Fabero, F.; Cuenca, J.; Mejuto, E.; De Lucas, J. Abstract: In this work, the method for calculation of uncertainty of pyrheliometers’ responsivity during their outdoor calibration process in the laboratory is exposed. It is applied first for calibration of standard pyrheliometers by comparison to cavity radiometers, and after for calibration of an end-user pyrheliometer against that standard pyrheliometer. The dissemination of the WRR irradiance scale is illustrated in practice and the increasing uncertainty in the traceability chain is quantified. The way of getting traceability to both WRR scale and to SI units in the current situation, where the shift between these radiometric scales is pending to be solved, is also explained. However, the impact of this gap between scales seems to be more important for calibrations of reference Class A pyrheliometers than in the final determination of DNI irradiance, because in this case, the cumulative uncertainty is large enough as to not significantly be affected for the difference. The way to take into account different correction terms in the measurement model function, and how to compute the corresponding uncertainty, is explained too. The influence of temperature of some pyrheliometers during calibration process and the potential impact on the DNI irradiance calculated with these instruments is exemplified.

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