Estimation of the diffuse solar irradiation from global solar irradiation. Daily and monthly average daily values

Martínez‐Lozano, J. A.; Utrillas, M. P.; Gómez, Verònica Zaragoza

doi:10.1016/0960-1481(94)90069-8

Cited by 14 publications

(5 citation statements)

References 40 publications

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“…It is called the clearness index because it decreases with increasing atmospheric attenuation of solar radiation, mostly determined by cloudiness. The true physical value of the clearness index is instantaneous although it can be used also with hourly values Ogunjobi and Kim, 2004), daily values (Martínez-Lozano et al, 1994a;Kudish and Ianetz, 1996;Ulgen and Hepbasli, 2002;Santos et al, 2003) or monthly values (Udo, 2000;Ulgen and Hepbasli, 2002;Kudish et al, 2005). In order to study the total UV radiation, Martínez-Lozano et al (1994b) defined an ultraviolet clearness index k tUV , with a similar form to k t but referring only to the UV spectral range and using the solar constant for UV radiation, I SCUV (81.13 Wm −2 ) obtained from the SUSIM Atlas 3 extraterrestrial spectrum (http://www.solar.nrl.navy.mil/susim atlas data.…”

Section: Introductionmentioning

confidence: 99%

The erythemal clearness index for Valencia, Spain

Tena

Martínez‐Lozano

Utrillas

et al. 2008

Intl Journal of Climatology

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ABSTRACT:The values of three clearness indices have been measured for the city of Valencia: k t , the clearness index for the whole solar spectrum, k tUV the clearness index for the ultraviolet range, and the erythemal clearness index for the erythemal radiation k tUVER , corresponding to the solar radiation weighted by the erythemal action spectrum on human skin, normalized with respect to the solar constant corresponding to that spectrum. The measurements of k tUV reached values that were approximately 54% of that corresponding to k t , while those of k tUVER were much smaller. Some statistics of the erythemal clearness index have been calculated both for monthly as well as hourly means. The shape of the distribution in both cases was nearly normal, so standard deviation and variance were used to analyse the dispersion of the data. The ratio of the erythemal clearness index and the corresponding solar irradiance was also studied. When only the central hours of the day were considered the relation between the two was markedly linear, giving a correlation coefficient that reached 99%.

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Section: Introductionmentioning

confidence: 99%

The erythemal clearness index for Valencia, Spain

Tena

Martínez‐Lozano

Utrillas

et al. 2008

Intl Journal of Climatology

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“…This result is completely different to the one obtained when the models were applied to the global irradiance (radiation from 0.3 to 3 μm), where the Isotropic model presented the greatest discrepancies with respect to the experimental data (16). This is because the UVER has a greater fraction of diffuse component and it is more isotropic than at longer wavelengths, which reaches at least 60% even under the clearest sky conditions in Valencia (Spain) (25), whereas the diffuse component for global irradiance only represents about 10% of the total (38), for cloud‐free skies. Therefore models tend to underestimate the diffuse UVER component if they were developed for global broadband radiation.…”

Section: Resultsmentioning

confidence: 99%

“…The reason for the errors being higher when we consider cloudless days only is because the models were developed for broadband radiation, where the diffuse component is only about 10% of the total radiation (38). For the UVER range, the diffuse component reaches on cloudless days, as a minimum, values of 60% (25), and the anisotropy conditions are intensified with respect to the predictions of the models.…”

Section: Resultsmentioning

confidence: 99%

Diffuse Ultraviolet Erythemal Irradiance on Inclined Planes: A Comparison of Experimental and Modeled Data

Utrillas

Marı́n

Esteve

et al. 2009

Photochem & Photobiology

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Values of measured and modeled diffuse UV erythemal irradiance (UVER) for all sky conditions are compared on planes inclined at 40 degrees and oriented north, south, east and west. The models used for simulating diffuse UVER are of the geometric-type, mainly the Isotropic, Klucher, Hay, Muneer, Reindl and Schauberger models. To analyze the precision of the models, some statistical estimators were used such as root mean square deviation, mean absolute deviation and mean bias deviation. It was seen that all the analyzed models reproduce adequately the diffuse UVER on the south-facing plane, with greater discrepancies for the other inclined planes. When the models are applied to cloud-free conditions, the errors obtained are higher because the anisotropy of the sky dome acquires more importance and the models do not provide the estimation of diffuse UVER accurately.

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“…Veeran and Kumar 26 analyzed 5 years data of solar radiation and established correlation between monthly mean clearness index with DSR. Martinez‐Lozano et al 27 evaluated the most accurate models for calculating solar radiation components for a location and placed the PV panels on tilted surface to enhance solar intensity. Gopinathan and Soler 28 analyzed several years of measured data from 40 widely scattered locations and estimated DSR on horizontal surfaces.…”

Section: Introductionmentioning

confidence: 99%

Deterministic and probabilistic analysis of different empirical models to estimate monthly mean diffuse solar radiation for composite climatic region of India

Singh

Akella

Manna

2022

Env Prog and Sustain Energy

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This research compares the performance of the models to estimate monthly mean diffuse solar radiation (DSR) on a horizontal surface for composite climatic region of India. The goal is to identify the most accurate model using deterministic and probabilistic analysis through two levels of uncertainty in daily sunshine period to examine the accuracy of the model that will be used to estimate DSR in the region under consideration. The meteorological data were collected from Indian Meteorological Department for the city of New Delhi (28 34 0 N, 77 12 0 E) which comes under composite climatic region prescribed by the Energy Conservation Building Code for India.From the literature, 150 typical models were chosen and categorized into three categories correlating diffuse fraction to sky-clearness index and relative sunshine period.The models are statistically evaluated using well-known statistical indicators in a unique way. In addition, the global performance indicator (GPI) is calculated using scaled values of indicators. The GPI of the chosen models ranged from À2.2912 to 0.2584, with the greatest value indicating the best model. Following that, the models are then ranked in decreasing order of GPI. Finally, the performances of the models are also checked for different locations having similar climatic conditions. Thus, results of this work are useful for impoverished countries as well as remote areas having similar environment conditions.

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Estimation of the diffuse solar irradiation from global solar irradiation. Daily and monthly average daily values

Cited by 14 publications

References 40 publications

The erythemal clearness index for Valencia, Spain

The erythemal clearness index for Valencia, Spain

Diffuse Ultraviolet Erythemal Irradiance on Inclined Planes: A Comparison of Experimental and Modeled Data

Deterministic and probabilistic analysis of different empirical models to estimate monthly mean diffuse solar radiation for composite climatic region of India

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