Using Isotropic and Anisotropic Models to Determine Solar Module Tilt to Maximize Incident Energy and PV Electricity Output on the Alaska North Slope

2020 ◽  
Author(s):  
Kurt Wurthmann
Keyword(s):  
Solar Radiation ◽  
Diffuse Radiation ◽  
Early Spring ◽  
North Slope ◽  
Late Winter ◽  
Anisotropic Model ◽  
Pv System ◽  
Solar Module ◽  
Incident Solar Radiation ◽  
Anisotropic Models

Abstract The Alaska North Slope is a pristine and fragile arctic environment that needs protection. The present article illustrates the application of isotropic and anisotropic models for predicting solar radiation on photovoltaic (PV) modules (and, hence, potential electricity output) for different angles of inclination (or tilt) in Utqiagvik Alaska. The anisotropic model is shown to provide higher, albeit more accurate, predictions of solar radiation since it includes all of the measures used in the isotropic model, but provides a more comprehensive representation of the diffuse component. Specifically, the anisotropic model includes not only the isotropic part of diffuse radiation, but also the circumsolar and horizon brightening parts. A PV array angle of tilt of 55 degrees is shown to provide the greatest total amount of incident solar radiation for the entire year, based on both the isotropic and anisotropic models. However, both models also indicate that angles of tilt that are steeper than 55 degrees result in slightly greater amounts of incident solar radiation during the late-winter, early-spring, and mid-fall months; while angles of tilt that are flatter than 55 degrees result in slightly greater amounts of incident solar radiation during the summer and early-fall months. It is shown that a PV system with a moderately sized array, tilted at the fixed angle of 55 degrees, could provide more than 50 percent of the total annual electricity needs for homes in Utqiagvik Alaska.

scholarly journals Annual evolution of global, direct and diffuse radiation and fractions in tilted surfaces

2012 ◽  
Vol 32 (2) ◽  
pp. 247-260
Author(s):  
Adilson P. de Souza ◽  
João F. Escobedo ◽  
Alexandre Dal Pai ◽  
Eduardo N. Gomes
Keyword(s):  
Solar Radiation ◽  
Cloud Cover ◽  
Diffuse Radiation ◽  
Incident Radiation ◽  
Sao Paulo ◽  
Horizontal Surface ◽  
Direct Radiation ◽  
Incident Solar Radiation ◽  
Cover Ratio ◽  
Atmospheric Transmissivity

It was evaluated the annual evolution of global, direct and diffuse components of incident solar radiation on tilted surfaces to 12.85, 22.85 and 32.85º, facing north, in Botucatu, state of São Paulo, Brazil. The radiometric fractions were obtained for each component of the radiation in the aforementioned surfaces, through the ratio with the global and top of the atmosphere radiations. Seasonality was evaluated based on monthly averages of daily values. The measures occurred between 04/1998 and 07/2001 at 22.85º; 08/2001 and 02/2003 at 12.85º; and from 03/2003 to 12/2007 at 32.85º, with concomitant measures in the horizontal surface (reference). The levels of global and direct radiation on tilted surfaces were lower in summer and higher in the equinoxes when compared with the horizontal. The diffuse radiation on tilted surfaces was lower in most months, with losses of up to 65%. A trend of increasing differences occurred between horizontal and tilted surfaces with the increase of the angle in all the components and fractions of incident radiation. The annual evolution of rainfall and cloud cover ratio directly affected the atmospheric transmissivity of direct and diffuse components in the region.

scholarly journals Modeling the Incident Solar Radiation of the City of N’Djamena (Chad) by the Capderou Method

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Mahamat Hassane Babikir ◽  
Donatien Njomo ◽  
Mahamat Barka ◽  
Mahamoud Youssouf Khayal ◽  
Deli Goron ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Diffuse Radiation ◽  
Theoretical Models ◽  
African Countries ◽  
Incident Solar Radiation ◽  
Diffuse Solar Radiation ◽  
Different Seasons ◽  
The Moment ◽  
Desert Climate

Chad is like many African countries with no meteorological station at the moment to measure solar radiation throughout the country. Thus, theoretical models are used to estimate incident solar radiation. These models are established in correlation form. Our objective was to present a model, which allows the determination of the solar component on two surfaces (horizontal and inclined). This model allowed us to determine, over time, the component of global, direct, and diffuse solar radiation over a period that will cover the different seasons of the year. The calculation is done according to Klein’s days over all the months of the year. The hourly results of the global, direct, and diffuse radiation obtained for all the planes going from January to December are satisfactory compared to the results of the other authors quoted in the literature, which give the maximum and minimum values very close to theirs. These results allowed us to validate the applicability of this model in a climate other than the desert climate.

scholarly journals Influence of Pollen on Solar Photovoltaic Energy: Literature Review and Experimental Testing with Pollen

2020 ◽  
Vol 10 (14) ◽  
pp. 4733
Author(s):  
Carlos Sanz Saiz ◽  
Jesús Polo Martínez ◽  
Nuria Martín Chivelet
Keyword(s):  
Experimental Testing ◽  
Mass Density ◽  
Soda Lime ◽  
Float Glass ◽  
Early Spring ◽  
Late Winter ◽  
Solar Photovoltaic ◽  
Pv System ◽  
The Impact ◽  
Pv Power Generation

This work attempts to shed some light on the impact of organic soiling due to pollen on solar photovoltaic (PV) power generation. Apart from introducing several soiling-related pollen features, the previous works reporting soiling by pollen have been reviewed. Local observations from late winter to early spring showed that a rooftop PV system experienced both uniform and non-uniform soiling issues, which were mainly caused by pollen from nearby cypress specimens. In addition, this work publishes preliminary results regarding an artificial soiling test performed with pollen. In this test, soda lime float glass coupons were artificially soiled with fresh cypress pollen. A linear relationship was found between the pollen mass density (ρA) and the glass averaged transmittance (TAVE) for values up to 9.1 g/m2. In comparison with other artificial soiling tests performed with different soiling agents, the transmittance loss caused by pollen cypress deposition was relatively high and spectrally selective.

scholarly journals Models for the Calculation of Diffuse Radiation on Solar Collectors

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Jovan Mikulović ◽  
Željko Đurišić
Keyword(s):  
Solar Radiation ◽  
Solar Irradiance ◽  
Least Squares Method ◽  
Measurement Data ◽  
Energy Systems ◽  
Diffuse Radiation ◽  
Weather Conditions ◽  
Solar Collectors ◽  
Diffuse Component ◽  
Anisotropic Models

For the design and exploitation of solar energy systems, information of both direct and diffuse component of solar radiation is necessary. However, the measurement data that are available are usually restricted to total horizontal irradiance. Therefore, many models have been developed to determine the diffuse component of the irradiance on solar collectors. This paper discusses the most well-known isotropic and anisotropic models for the calculation of the diffuse component of the solar irradiance. A modification of the isotropic clear day model for determining the diffuse component of solar radiation on a horizontal surface has been presented. The presented model has the same form as a simple clear day model, with the parameters determined using the least squares method and measurement data on horizontal irradiance in the region of Belgrade, Serbia. The applicability of isotropic clear day models was examined. The paper also discusses the applicability of the models for determining the diffuse irradiance on tilted collectors in real weather conditions during the year. The basic expressions are given and the characteristics of individual models are highlighted. Based on the measurement data on horizontal irradiance, the possibilities of applying different models for the calculation of the diffuse component of irradiance on solar collectors located in the region of Belgrade were examined.

scholarly journals DEVELOPMENT OF THE MONTHLY AVERAGE DAILY SOLAR RADIATION MAP USING A-CBR, FEM, AND KRIGING METHOD

2017 ◽  
Vol 24 (2) ◽  
pp. 489-512 ◽  
Author(s):  
Choongwan KOO ◽  
Taehoon HONG ◽  
Kwangbok JEONG ◽  
Jimin KIM
Keyword(s):  
Solar Radiation ◽  
Decision Makers ◽  
Estimation Accuracy ◽  
Case Based Reasoning ◽  
Final Decision ◽  
Kriging Method ◽  
Pv System ◽  
Fem Model ◽  
Remote Sensors ◽  
Monthly Average

Photovoltaic (PV) system could be implemented to mitigate global warming and lack of energy. To maximize its effectiveness, the monthly average daily solar radiation (MADSR) should be accurately estimated, and then an accurate MADSR map could be developed for final decision-makers. However, there is a limitation in improving the accuracy of the MADSR map due to the lack of weather stations. This is because it is too expensive to measure the actual MADSR data using the remote sensors in all the sites where the PV system would be installed. Thus, this study aimed to develop the MADSR map with improved estimation accuracy using the advanced case-based reasoning (A-CBR), finite element method (FEM), and kriging method. This study was conducted in four steps: (i) data collection; (ii) estimation of the MADSR data in the 54 unmeasured locations using the A-CBR model; (iii) estimation of the MADSR data in the 89 unmeasured locations using the FEM model; and (iv) development of the MADSR map using the kriging method. Compared to the previous MADSR map, the proposed MADSR map was determined to be improved in terms of its estimation accuracy and classification level.

scholarly journals Utilising Open Geospatial Data to Refine Weather Variables for Building Energy Performance Evaluation—Incident Solar Radiation and Wind-Driven Infiltration Modelling

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 802
Author(s):  
Kristian Skeie ◽  
Arild Gustavsen
Keyword(s):  
Solar Radiation ◽  
Web Service ◽  
Meteorological Data ◽  
Surface Wind ◽  
Building Energy ◽  
Energy Performance ◽  
Geospatial Data ◽  
Weather Data ◽  
Building Site ◽  
Incident Solar Radiation

In building thermal energy characterisation, the relevance of proper modelling of the effects caused by solar radiation, temperature and wind is seen as a critical factor. Open geospatial datasets are growing in diversity, easing access to meteorological data and other relevant information that can be used for building energy modelling. However, the application of geospatial techniques combining multiple open datasets is not yet common in the often scripted workflows of data-driven building thermal performance characterisation. We present a method for processing time-series from climate reanalysis and satellite-derived solar irradiance services, by implementing land-use, and elevation raster maps served in an elevation profile web-service. The article describes a methodology to: (1) adapt gridded weather data to four case-building sites in Europe; (2) calculate the incident solar radiation on the building facades; (3) estimate wind and temperature-dependent infiltration using a single-zone infiltration model and (4) including separating and evaluating the sheltering effect of buildings and trees in the vicinity, based on building footprints. Calculations of solar radiation, surface wind and air infiltration potential are done using validated models published in the scientific literature. We found that using scripting tools to automate geoprocessing tasks is widespread, and implementing such techniques in conjunction with an elevation profile web service made it possible to utilise information from open geospatial data surrounding a building site effectively. We expect that the modelling approach could be further improved, including diffuse-shading methods and evaluating other wind shelter methods for urban settings.

Seasonal activity and estivation of lumbricid earthworms in the midlands of Tasmania

Soil Research ◽  
1994 ◽  
Vol 32 (6) ◽  
pp. 1355 ◽  
Author(s):  
RB Garnsey
Keyword(s):  
Soil Moisture ◽  
Adult Development ◽  
Survival Rates ◽  
Soil Surface ◽  
Early Spring ◽  
Lumbricus Rubellus ◽  
Late Winter ◽  
Cocoon Production ◽  
Density And Biomass ◽  
Earthworm Activity

Earthworms have the ability to alleviate many soil degradational problems in Australia. An attempt to optimize this resource requires fundamental understanding of earthworm ecology. This study reports the seasonal changes in earthworm populations in the Midlands of Tasmania (<600 mm rainfall p.a.), and examines, for the first time in Australia, the behaviour and survival rates of aestivating earthworms. Earthworms were sampled from 14 permanent pastures in the Midlands from May 1992 to February 1994. Earthworm activity was significantly correlated with soil moisture; maximum earthworm activity in the surface soil was evident during the wetter months of winter and early spring, followed by aestivation in the surface and subsoils during the drier summer months. The two most abundant earthworm species found in the Midlands were Aporrectodea caliginosa (maximum of 174.8 m-2 or 55.06 g m-2) and A. trapezoides (86 m-2 or 52.03 g m-2), with low numbers of Octolasion cyaneum, Lumbricus rubellus and A. rosea. The phenology of A. caliginosa relating to rainfall contrasted with that of A. trapezoides in this study. A caliginosa was particularly dependent upon rainfall in the Midlands: population density, cocoon production and adult development of A. caliginosa were reduced as rainfall reduced from 600 to 425 mm p.a. In contrast, the density and biomass of A. trapezoides were unaffected by rainfall over the same range: cocoon production and adult development continued regardless of rainfall. The depth of earthworm aestivation during the summers of 1992-94 was similar in each year. Most individuals were in aestivation at a depth of 150-200 mm, regardless of species, soil moisture or texture. Smaller aestivating individuals were located nearer the soil surface, as was shown by an increase in mean mass of aestivating individuals with depth. There was a high mortality associated with summer aestivation of up to 60% for juvenile, and 63% for adult earthworms in 1993 in the Midlands. Cocoons did not survive during the summers of 1992 or 1994, but were recovered in 1993, possibly due to the influence of rainfall during late winter and early spring.

Improved Accuracy Models For Hourly Diffuse Solar Radiation

2005 ◽  
Vol 128 (1) ◽  
pp. 104-117 ◽  
Author(s):  
T. Muneer ◽  
S. Munawwar
Keyword(s):  
Solar Radiation ◽  
Regression Models ◽  
Global Radiation ◽  
Diffuse Radiation ◽  
Evaluation Procedure ◽  
Accuracy Score ◽  
Error Statistics ◽  
Diffuse Solar Radiation ◽  
Energy Applications ◽  
Extensive Evaluation

Solar energy applications require readily available, site-oriented, and long-term solar data. However, the frequent unavailability of diffuse irradiation, in contrast to its need, has led to the evolution of various regression models to predict it from the more commonly available data. Estimating the diffuse component from global radiation is one such technique. The present work focuses on improvement in the accuracy of the models for predicting horizontal diffuse irradiation using hourly solar radiation database from nine sites across the globe. The influence of sunshine fraction, cloud cover, and air mass on estimation of diffuse radiation is investigated. Inclusion of these along with hourly clearness index, leads to the development of a series of models for each site. Estimated values of hourly diffuse radiation are compared with measured values in terms of error statistics and indicators like, R2, mean bias deviation, root mean square deviation, skewness, and kurtosis. A new method called “the accuracy score system” is devised to assess the effect on accuracy with subsequent addition of each parameter and increase in complexity of equation. After an extensive evaluation procedure, extricate but adequate models are recommended as optimum for each of the nine sites. These models were found to be site dependent but the model types were fairly consistent for neighboring stations or locations with similar climates. Also, this study reveals a significant improvement from the conventional k-kt regression models to the presently proposed models.

Rotifer dynamics in three shallow lakes from the Salado river watershed (Argentina): the potential modulating role of incident solar radiation

2015 ◽  
Vol 14 (11) ◽  
pp. 2007-2013 ◽  
Author(s):  
Nadia Diovisalvi ◽  
Armando M. Rennella ◽  
Horacio E. Zagarese
Keyword(s):  
Solar Radiation ◽  
Shallow Lakes ◽  
Seasonal Cycle ◽  
Schematic Representation ◽  
Incident Solar Radiation ◽  
River Watershed ◽  
Clear Sky ◽  
Rotifer Species ◽  
Salado River

A schematic representation of the seasonal cycle of rotifer in L. Chascomús. In this figure the relative abundances of the three dominant rotifer species are expressed as fractions of the estimated clear-sky mean daily incident solar radiation.

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