Research

14 pages, 4246 KiB

Open AccessArticle

Erythemal Solar Irradiance, UVER, and UV Index from Ground-Based Data in Central Spain

by Julia Bilbao and Argimiro de Migue

Appl. Sci. 2020, 10(18), 6589; https://doi.org/10.3390/app10186589 - 21 Sep 2020

Cited by 16 | Viewed by 5187

The study shows an analysis of a 7-year data set measuring Ultraviolet-B (UVB) irradiance values and ultraviolet index TABLEUVI) values derived from ground-based broadband irradiance measurements, satellite-derived total ozone, and UVB solar irradiance recorded in Valladolid (Central Spain). Ultraviolet-B (UVB) solar irradiance measurements [...] Read more.

The study shows an analysis of a 7-year data set measuring Ultraviolet-B (UVB) irradiance values and ultraviolet index TABLEUVI) values derived from ground-based broadband irradiance measurements, satellite-derived total ozone, and UVB solar irradiance recorded in Valladolid (Central Spain). Ultraviolet-B (UVB) solar irradiance measurements in the range (280–315 nm) carried out during the period 2013–2019 at a continental Mediterranean solar station, located in Valladolid (Spain), were analyzed. UVB data recorded using a YES UVB-1 pyranometer were used to estimate erythemal irradiance, ultraviolet erythemal irradiance (UVER), UVI, cumulative dose, and sun protection. Hourly UVER data in January (minimum values) and June (maximum values) were analyzed as an average year for the measurement station. Differences between UVI values at solar noon and the maximum daily value were minimal. It was found that on certain summer days, maximum daily UVI and SED (cumulative daily dose) could be over 12 and 60, respectively. The cumulative dose on the horizontal surface was calculated at the station for different skin types. It was observed that over 45% of the annual dose is received in summer, about 30% in spring, over 15% in autumn, and less than 10% in winter. In addition, the relationship between the maximum daily UVI and the annual accumulated dose in SEDs was studied to provide information on sun protection under low UVI conditions. Full article

(This article belongs to the Special Issue Solar Radiation: Measurements and Modelling, Effects and Applications)

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16 pages, 5207 KiB

Open AccessArticle

GPU-Enabled Shadow Casting for Solar Potential Estimation in Large Urban Areas. Application to the Solar Cadaster of Greater Geneva

by Nabil Stendardo, Gilles Desthieux, Nabil Abdennadher and Peter Gallinelli

Appl. Sci. 2020, 10(15), 5361; https://doi.org/10.3390/app10155361 - 03 Aug 2020

Cited by 14 | Viewed by 2709

Abstract

In the context of encouraging the development of renewable energy, this paper deals with the description of a software solution for mapping out solar potential in a large scale and in high resolution. We leverage the performance provided by Graphics Processing Units (GPUs) [...] Read more.

In the context of encouraging the development of renewable energy, this paper deals with the description of a software solution for mapping out solar potential in a large scale and in high resolution. We leverage the performance provided by Graphics Processing Units (GPUs) to accelerate shadow casting procedures (used both for direct sunlight exposure and the sky view factor), as well as use off-the-shelf components to compute an average weather pattern for a given area. Application of the approach is presented in the context of the solar cadaster of Greater Geneva (2000 km²). The results show that doing the analysis on a square tile of 3.4 km at a resolution of 0.5 m takes up to two hours, which is better than what we were achieving with the previous work. This shows that GPU-based calculations are highly competitive in the field of solar potential modeling. Full article

(This article belongs to the Special Issue Solar Radiation: Measurements and Modelling, Effects and Applications)

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17 pages, 3755 KiB

Open AccessArticle

Influence of Surface Reflection (Albedo) in Simulating the Sun Drying of Paddy Rice

by Ana Salvatierra-Rojas, Victor Torres-Toledo and Joachim Müller

Appl. Sci. 2020, 10(15), 5092; https://doi.org/10.3390/app10155092 - 24 Jul 2020

Cited by 4 | Viewed by 2741

Abstract

The sun drying of agricultural products is a complicated process involving heat transfer, mass transfer, and variable weather conditions. Surface reflection (albedo), a crop’s radiative property, plays an essential role in energy balance, and understanding its contribution can improve the thermal analysis. In [...] Read more.

The sun drying of agricultural products is a complicated process involving heat transfer, mass transfer, and variable weather conditions. Surface reflection (albedo), a crop’s radiative property, plays an essential role in energy balance, and understanding its contribution can improve the thermal analysis. In this study, field experiments were conducted in the Philippines to explore the influence of surface albedo on the sun drying of paddy rice. First, we implemented energy and mass balance equations in a transient model with the surroundings using a graphical programming language in Matlab/Simulink^®. Second, we identified the influence of albedo on the sun drying model by using a sensitivity analysis. Third, we investigated the relationship of paddy rice albedo and the solar zenith angle. Lastly, we integrated the albedo function into the sun drying model. The simulation outputs were validated with field experiments. A better estimation of the measured exit temperature and instantaneous mass were obtained when a variable albedo was applied. This study makes clear that introducing a variable albedo has a positive impact on model improvement. This information is important for application in solar drying technologies, so that the drying process can be better assessed. Full article

(This article belongs to the Special Issue Solar Radiation: Measurements and Modelling, Effects and Applications)

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22 pages, 2291 KiB

Open AccessArticle

The Buying Time Argument within the Solar Radiation Management Discourse

by Frederike Neuber and Konrad Ott

Appl. Sci. 2020, 10(13), 4637; https://doi.org/10.3390/app10134637 - 04 Jul 2020

Cited by 6 | Viewed by 3381

Abstract

In this article, we will establish a version of the buying time argument (BTA) in favor of Sulphur Aerosol Injection (SAI) Climate Engineering (CE). The idea is not to promote the deployment of such scheme, but rather to present the strongest possible argument [...] Read more.

In this article, we will establish a version of the buying time argument (BTA) in favor of Sulphur Aerosol Injection (SAI) Climate Engineering (CE). The idea is not to promote the deployment of such scheme, but rather to present the strongest possible argument pro SAI in order to look at its presuppositions, implications, critical points and uncertainties. In discussing BTA being the only morally sound argument in favor of SAI, the stakes and the overall framework will become visible. If, however, the strongest pro-SAI argument enables us to recognize some major flaws of this technology, this option should be disregarded. Full article

(This article belongs to the Special Issue Solar Radiation: Measurements and Modelling, Effects and Applications)

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31 pages, 11577 KiB

Open AccessFeature PaperArticle

Climatology of the Linke and Unsworth–Monteith Turbidity Parameters for Greece: Introduction to the Notion of a Typical Atmospheric Turbidity Year

by Harry D. Kambezidis and Basil E. Psiloglou

Appl. Sci. 2020, 10(11), 4043; https://doi.org/10.3390/app10114043 - 11 Jun 2020

Cited by 10 | Viewed by 2802

Abstract

Solar rays are attenuated by the Earth’s atmosphere. This attenuation can be expressed by the turbidity parameters; two of them are the Linke turbidity factor (T_L) and the Unsworth–Monteith turbidity coefficient (T_UM). In this sudy, both parameters [...] Read more.

Solar rays are attenuated by the Earth’s atmosphere. This attenuation can be expressed by the turbidity parameters; two of them are the Linke turbidity factor (T_L) and the Unsworth–Monteith turbidity coefficient (T_UM). In this sudy, both parameters are estimated for 33 sites across Greece, and the notion of a Typical Atmospheric Turbidity Year (TATY) is also introduced. Use of the modified clearness index (k’_t) is made, while a suggestion for a modified diffuse fraction (k’_d) is given. The adoption of the four climatic zones in Greece for energy purposes is made, where the variation of T_L and T_UM is studied during a TATY under all and clear-sky conditions. The analysis shows maximum levels in both parameters in late winter–early spring in morning and evening hours, with minimum values at midday. The intra-annual variation of the parameters shows maximum values around March and August and minimum values in summertime and late winter. Maps of annual mean T_L and T_UM values over Greece show persistent minimum values over Peloponnese and maximum values over South Ionian Sea. Linear expressions of T_UM vs. T_L are derived for all sites under all and clear-sky conditions. Finally, linear expressions for k’_d vs. k’_t are given for all sites and sky conditions. Full article

(This article belongs to the Special Issue Solar Radiation: Measurements and Modelling, Effects and Applications)

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15 pages, 3941 KiB

Open AccessArticle

Evaluation of the Vertical Sky Component without Obstructions for Daylighting in Burgos, Spain

by Diego Granados-López, Montserrat Díez-Mediavilla, M. Isabel Dieste-Velasco, Andrés Suárez-García and Cristina Alonso-Tristán

Appl. Sci. 2020, 10(9), 3095; https://doi.org/10.3390/app10093095 - 29 Apr 2020

Cited by 4 | Viewed by 4364

Abstract

Daylight availability knowledge is the first step for an energetic and visually efficient building and city design. It can be estimated with the Vertical Sky Component (VSC), which is defined as the ratio of the vertical diffuse illuminance over the unobstructed horizontal diffuse [...] Read more.

Daylight availability knowledge is the first step for an energetic and visually efficient building and city design. It can be estimated with the Vertical Sky Component (VSC), which is defined as the ratio of the vertical diffuse illuminance over the unobstructed horizontal diffuse illuminance, simultaneously measured at the same point. These illuminance magnitudes are obtained from luxmeter measurements but these data are scarce. Alternatively, VSC can be obtained from prior knowledge of the sky illuminance distribution, which can be measured with a sky scanner device or by reference to the CIE (Commission Internationale de L’Éclairage) Standard classification for homogeneous skies. Both approaches are compared in this study. The coherence of the results obtained for the four cardinal orientations are analyzed by applying classical statistical parameters and luxmeter measurements as references for the results. The measurement campaign was completed between September 2016 and January 2019 in Burgos (Spain), as representative case study and specific contribution of this work. It was observed that the VSC values were higher than 100 in many cases: 21.94% for the south- and 33.6% for the east-facing vertical surfaces. The study highlights the good daylighting conditions in Burgos, mainly due to the predominance of clear skies over much of the year. This fact implies high daylight availability that, with efficient city planning and building design, could potentially lead reduction energy consumption of buildings, improvements in visual comfort, and the well-being of occupants. Full article

(This article belongs to the Special Issue Solar Radiation: Measurements and Modelling, Effects and Applications)

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9 pages, 1297 KiB

Open AccessArticle

Estimating Daily Global Solar Radiation with No Meteorological Data in Poland

by Małgorzata Kleniewska, Dorota Mitrowska and Michał Wasilewicz

Appl. Sci. 2020, 10(3), 778; https://doi.org/10.3390/app10030778 - 22 Jan 2020

Cited by 7 | Viewed by 3092

Abstract

The aim of the study was to calibrate coefficients and evaluate performance of simple, day-of-the-year, global solar radiation (H) models nominated from the literature. Day-of-the-year models enable estimation of global solar radiation when no meteorological data is available. The study used 16-year-long data [...] Read more.

The aim of the study was to calibrate coefficients and evaluate performance of simple, day-of-the-year, global solar radiation (H) models nominated from the literature. Day-of-the-year models enable estimation of global solar radiation when no meteorological data is available. The study used 16-year-long data series of daily H, taken at 15 actinometric stations located in various parts of Poland. The goodness-of-fit of the models to the actual long-term monthly average daily global solar radiation data expressed by determination coefficient (R2) ranges from 0.94 to 0.97. Depending on statistical indicators analysis (root mean square error—RMSE, mean absolute bias error—MABE, mean average percentage error—MAPE) the best model was selected. The averaged values of H computed by the recommended model deviate from those measured by 4.16% to 8.71%. Locally calibrated, day-of-the-year model provides satisfactory accuracy and—where meteorological data is unavailable—can be used to estimate mean monthly daily global solar radiation in Poland and similar climate conditions. Full article

(This article belongs to the Special Issue Solar Radiation: Measurements and Modelling, Effects and Applications)

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15 pages, 7087 KiB

Open AccessArticle

Accurate Output Forecasting Method for Various Photovoltaic Modules Considering Incident Angle and Spectral Change Owing to Atmospheric Parameters and Cloud Conditions

by Hiroki Tawa, Hiromu Saiki, Yasuyuki Ota, Kenji Araki, Tatsuya Takamoto and Kensuke Nishioka

Appl. Sci. 2020, 10(2), 703; https://doi.org/10.3390/app10020703 - 19 Jan 2020

Cited by 19 | Viewed by 4984

Abstract

Because semiconductors absorb wavelengths dependent on the light absorption coefficient, photovoltaic (PV) energy output is affected by the solar spectrum. Therefore, it is necessary to consider the solar spectrum for highly accurate PV output estimation. Bird’s model has been used as a general [...] Read more.

Because semiconductors absorb wavelengths dependent on the light absorption coefficient, photovoltaic (PV) energy output is affected by the solar spectrum. Therefore, it is necessary to consider the solar spectrum for highly accurate PV output estimation. Bird’s model has been used as a general spectral model. However, atmospheric parameters such as aerosol optical depth and precipitable water have a constant value in the model that only applies to clear days. In this study, atmospheric parameters were extracted using the Bird’s spectrum model from the measured global spectrum and the seasonal fluctuation of atmospheric parameters was examined. We propose an overcast spectrum model and calculate the all-weather solar spectrum from clear to overcast sky through linear combination. Three types of PV modules (fixed Si, two-axis tracking Si, and fixed InGaP/GaAs/InGaAs triple-junction solar cells) were installed at the University of Miyazaki. The estimated performance ratio (PR), which takes into account incident angle and spectral variations, was consistent with the measured PR. Finally, the energy yield of various PVs installed across Japan was successfully estimated. Full article

(This article belongs to the Special Issue Solar Radiation: Measurements and Modelling, Effects and Applications)

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