scholarly journals Solar Radiation on a Parabolic Concave Surface

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2245
Author(s):  
Avi Aronescu ◽  
Joseph Appelbaum
Keyword(s):  
Solar Radiation ◽  
Concave Surface ◽  
The South ◽  
Oriented Surface ◽  
Incident Solar Radiation ◽  
Photovoltaic Modules ◽  
Curved Structures ◽  
Global Irradiation ◽  
The Difference ◽  
Analytical Expressions

Curved structures are used in buildings and may be integrated with photovoltaic modules. Self-shading occurs on non-flat (curved) surface collectors resulting in a non-uniform distribution of the direct beam and the diffuse incident solar radiation along the curvature the surface. The present study uses analytical expressions for calculating and analyzing the incident solar radiation on a general parabolic concave surface. Concave surfaces facing north, south and east/west are considered, and numerical values for the annual incident irradiations (in kWh) are demonstrated for two locations: 32° N (Tel Aviv, Israel) and 52.2° N (Lindenberg, Germany). The numerical results show that the difference in the incident global irradiation for the different surface orientations is not very wide. At 32° N, the irradiation difference between the south and north-oriented surface is about 15 percent, and between the south and east surface orientation it is about 9.6 percent. For latitude 52.2° N, the global irradiation difference between the south and north-oriented surface is about 16 percent, and between the south and east orientation it is about 3 percent.

scholarly journals Estimation of Incident Solar Radiation on the Walls of a Habitat for the Typical Day of April in the Ouagadougou Region in Burkina Faso

2020 ◽  
Vol 5 (9) ◽  
pp. 1128-1132
Author(s):  
Baba MANSARE ◽  
Mamadouba CONTE ◽  
Yacouba CAMARA ◽  
Amadou Lamarana BAH ◽  
Drissa OUEDRAOGO
Keyword(s):  
Mathematical Model ◽  
Solar Radiation ◽  
Burkina Faso ◽  
Programming Language ◽  
Solar Flux ◽  
The South ◽  
Incident Solar Radiation ◽  
Typical Day ◽  
Set Up ◽  
Fortran Programming Language

His work aims to develop a mathematical model of incident solar radiation on all the walls of a sloping roof habitat for a typical climate in the Ouagadougou region. Subsequently, we set up a program for the calculations of the essential parameters of illumination and the various components of solar radiation under the Fortran Programming Language and to plot our curves using the Origin software. This work allowed us to estimate the amount of solar flux that each wall of a habitat receives during a day, to know the importance of the orientation of the main facade of the habitat to the south and to find out how often the roof is exposed to solar radiation.

Is ‘Reflectance’ Basking Real?

1990 ◽  
Vol 154 (1) ◽  
pp. 31-43
Author(s):  
BERND HEINRICH
Keyword(s):  
Solar Radiation ◽  
Opposite Direction ◽  
Acute Angle ◽  
Direct Sunlight ◽  
Convective Cooling ◽  
Incident Solar Radiation ◽  
Solar Reflectance ◽  
Thoracic Temperature ◽  
Air Stream ◽  
The Difference

Various kinds of butterflies raise both (or sometimes one) of their pairs of wings while basking with their body at approximately right angles to the incident solar radiation and with their wings held at an acute angle to the incident sunlight. I here test the effects of wing posture on thoracic temperature in so-called ‘reflectance’ basking. 1. Butterflies with pale yellow or white dorsal wing surfaces held with their wings at 45, 90 or 180° with respect to each other (or 22–23, 45 and 90°with respect to the solar radiation) heated to mean thoracic temperatures (Tth) of 38.2, 39.5 and 39.9°C, respectively, in direct sunlight. These closely similar values of T^ are significantly different (P < 0.02) from each other, but the difference is in the opposite direction to that predicted by the solar reflectance hypothesis. 2. The Tth of butterflies tested under a sun lamp in the laboratory showed the same trend of Tth with wing angle. Reflectance from the wings thus makes little or no practical contribution to the animal's heating response. 3. Butterflies with wings at 45° that were heated from above with a sun lamp showed an immediate increase in Tth when turned at right angles to a gentle air stream. Thoracic temperature immediately declined when they were again turned to face the air stream. 4. Those butterflies that were at right angles to the air stream showed an immediate increase in Tth when the wings were raised from 180 to 45°, and their Tth again declined to previous values when the wings were again lowered. However, little or no effect of wing angle on Tth was observed when the wing angle of butterflies parallel to the air stream was altered. These results indicate that wing elevation in basking butterflies does not increase Tth by way of solar reflection from the wings. Instead, the raised wings increase Tth by reducing convective cooling. ‘Reflectance’ basking is a form of dorsal basking used by species of butterflies that perch above vegetation rather than above a heated substratum.

scholarly journals Impact of New Solar Radiation Parameterization in the Eta Model on the Simulation of Summer Climate over South America

2006 ◽  
Vol 45 (2) ◽  
pp. 318-333 ◽  
Author(s):  
T. A. Tarasova ◽  
J. P. R. Fernandez ◽  
I. A. Pisnichenko ◽  
J. A. Marengo ◽  
J. C. Ceballos ◽  
...  
Keyword(s):  
Solar Radiation ◽  
South America ◽  
Surface Air Temperature ◽  
Surface Flux ◽  
Global Precipitation Climatology Project ◽  
South Atlantic Convergence Zone ◽  
Horizontal Resolution ◽  
The South ◽  
Near Surface ◽  
Incident Solar Radiation

Abstract The regional Eta workstation (WS) model with horizontal resolution of 40 km has been integrated over South America for January 2003. The NCEP–DOE Reanalysis II was used for initial and lateral boundary conditions. The comparison of the model-simulated and satellite-derived values of monthly mean incident solar radiation at the surface demonstrates that the former values are larger by 20%–30% over the entire region. To improve the surface flux representation in the model, a new solar radiation scheme has been implemented in it. An offline comparison of the original and the new radiation schemes with the detailed line-by-line method demonstrates a higher accuracy for the new scheme. With the new scheme, the model-simulated incident solar radiation at the surface is in a better agreement with the satellite-derived data. Nevertheless, a noticeable systematic difference of 10%–20% still remains, probably because of the incorrect description of cloud parameters in the model. The lower incident solar radiation in the new version of the model causes a decrease of near-surface air temperature by 0.1°–1°C and a decrease of precipitation rate by up to 20%–30% over most of the continent. The increase in the simulated incident solar radiation and temperature is found in the region of the South Atlantic convergence zone, which is responsible for the enhanced cloudiness and precipitation in the central and southeastern parts of Brazil during summer. The model results are compared with observational data of meteorological stations, the Global Precipitation Climatology Project (GPCP), and the South American Low-Level Jet Experiment (SALLJEX) and are discussed.

Building integrated photovoltaic modules and the integration of phase change materials for equatorial applications

2019 ◽  
Vol 41 (5) ◽  
pp. 634-652 ◽  
Author(s):  
A Karthick ◽  
K Kalidasa Murugavel ◽  
K Sudalaiyandi ◽  
A Muthu Manokar
Keyword(s):  
Solar Radiation ◽  
Phase Change ◽  
Tamil Nadu ◽  
Phase Change Materials ◽  
Residential Buildings ◽  
Electrical Energy ◽  
Building Structure ◽  
The South ◽  
Photovoltaic Modules ◽  
Building Integrated Photovoltaic

The performance of building integrated photovoltaic (BIPV) system depends on the geographical location and the incident angle of solar radiation. In this paper, a simple mathematical model has been developed to predict the performance of BIPV modules with and without phase change material (PCM). The effect of transmittance of the BIPV glass cover is studied with respect to incident solar radiation. The performance curves, annual energy and exergy gains are analysed for hot and humid climatic conditions of Kovilpatti (9°10′0′′N, 77°52′0′′E), Tamil Nadu, India. The annual electrical energy gains of the BIPV-PCM for the south orientation is (135 kWh) and the east orientation (110 kWh) obtained the minimum. Similarly, the annual electrical energy of the BIPV-PCM is maximum in the east orientation and minimum in the west orientation. The south orientation BIPV-PCM obtained the maximum energy (190 kWh) and exergy (27.3 kWh). The theoretically calculated results have good agreement with experimental results. Practical application: Integration of photovoltaic modules into the building structure has many benefits and challenges; before integrating into the building structure, the performance and impact of the BIPV module needs to be studied. This study will assist developers and designers to understand the likely performance of the BIPV modules and assess the benefit of integrated phase change materials for application in residential buildings in equatorial climate zones.

scholarly journals Spectral solar irradiance and its entropic effect on Earth's climate

2011 ◽  
Vol 2 (1) ◽  
pp. 45-70 ◽  
Author(s):  
W. Wu ◽  
Y. Liu ◽  
G. Wen
Keyword(s):  
Solar Radiation ◽  
Solar Irradiance ◽  
Conventional Approach ◽  
Incident Solar Radiation ◽  
Earth’S Atmosphere ◽  
Radiation Entropy ◽  
Entropy Flux ◽  
The Difference ◽  
Earth’S Climate ◽  
Spectral Solar Irradiance

Abstract. The high-resolution measurements of the spectral solar irradiance at the top of the Earth's atmosphere by the Solar Radiation and Climate Experiment (SORCE) satellite suggest significant deviation of solar radiation from the commonly assumed blackbody radiation. Here, we use these spectral irradiance measurements to estimate the Earth's incident solar radiation entropy flux, and examine the importance of a proper estimation approach. The Earth's incident solar radiation entropy flux estimated by directly applying the observed spectral solar irradiance into the most accurate Planck expression is compared with that estimated with a conventional approach that uses the Sun's brightness temperature under the assumption of a blackbody Sun. The globally averaged non-blackbody incident solar radiation entropy flux at the top of the Earth's atmosphere equals 0.31 W m−2 K−1. This value is about 4 times larger than that estimated from the conventional blackbody approach, with the difference comparable to the typical value of the entropy production rate associated with atmospheric latent heat process. Further analysis reveals that the decrease of spectral solar radiation entropy flux with radiation traveling distance, unlike the decrease of spectral solar radiation energy flux with radiation traveling distance, is wavelength dependent, and that the difference between the two estimates can be attributed to the fact that the conventional approach ignores the influence of radiation traveling distance on the spectral solar radiation entropy flux. Moreover, sensitivity study further shows that the distribution of top-of-atmosphere spectral solar irradiance could significantly impact the magnitude of the estimated Earth's incident solar radiation entropy flux. These results together suggest that the spectral distribution of incident solar radiation is critical for determining the Earth's incident solar radiation entropy flux, and thus the Earth's climate.

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.

scholarly journals The role of L/W in the solar radiation for Saharian cities

2019 ◽  
Vol 91 ◽  
pp. 05006
Author(s):  
Rami Qaoud ◽  
Alkama Djamal
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Energy Levels ◽  
Direct Solar Radiation ◽  
Test Field ◽  
Natural Lighting ◽  
The Difference ◽  
The Impact ◽  
The Relationship

The urban fabric of the desert cities is based on the principle of reducing the impact of urban canyons on direct solar radiation. Here comes this research, which is based on a comparative study of the periods of direct solarisation and values of the solar energy of urban canyons via two urban fabrics that have different building densities, where the ratio between L/W is different. In order to obtain the real values of the solar energy (thermal, lighting), the test field was examined every two hours, each three consecutive days. The measurement stations are positioned by the three types of the relationship between L/W, (L≥2w, L=w, L≤0.5w). According to the results, we noticed and recorded the difference in the periods of direct solarization between the types of urban engineering canyons, reaching 6 hours a day, the difference in thermal values of air, reaching 4 °C, and the difference in periods of direct natural lighting, reaching 6 hours. It should be noted that the role of the relationship between L/W is to protect the urban canyons by reducing the impact of direct solar radiation on urban canyons, providing longer hours of shading, and reducing solar energy levels (thermal, lighting) at the urban canyons. This research is classified under the research axis (the studies of external spaces in the urban environment according to the bioclimatic approach and geographic approach). But this research aims to focus on the tracking and studying the distribution of the solar radiation - thermal radiation and lighting radiation - in different types of street canyons by comparing the study of the direct solarization periods of each type and the quantity of solar energy collected during the solarization periods.

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.

Solar Radiation and Earth Temperatures

1902 ◽  
Vol 23 ◽  
pp. 296-311
Author(s):  
C. G. Knott
Keyword(s):  
Solar Radiation ◽  
Direct Effect ◽  
Recent Meeting ◽  
The Mediterranean ◽  
The Difference

At a recent meeting of the Society, Dr Buchan read a paper based on certain observations of the temperature of the waters of the Mediterranean, which had been made by the staff of the Austrian ship Pola. These indicated that the direct effect of solar Tadiation was felt to a depth of over 150 feet. At any rate, the facts were that the temperature of the upper stratum of water of this thickness was perceptibly higher at about 4 p.m. than at 8 a.m., and that the difference was about 1°·5 Fahr. or 0°·8 Cent, at the surface, diminishing fairly steadily to value zero at a depth of fully 150 feet or 50 metres. It may easily be calculated that this excess of temperature at the afternoon hour means the accumulation of an amount of heat equal to 1460 units in every column of water 1 square centimetre in section; and this is accomplished within the eight hours from 8 a.m. to 4 p.m. It must be noted that this accumulation of heat is a daily occurrence.

scholarly journals The influence of observed and modelled net longwave radiation on the rate of estimated potential evapotranspiration

2019 ◽  
Vol 67 (3) ◽  
pp. 280-288 ◽  
Author(s):  
Jitka Kofroňová ◽  
Miroslav Tesař ◽  
Václav Šípek
Keyword(s):  
Czech Republic ◽  
Solar Radiation ◽  
Potential Evapotranspiration ◽  
Sunshine Duration ◽  
Longwave Radiation ◽  
Radiation Balance ◽  
Parameter Calibration ◽  
Atmospheric Emissivity ◽  
The Bohemian Forest ◽  
The Difference

Abstract Longwave radiation, as part of the radiation balance, is one of the factors needed to estimate potential evapotranspiration (PET). Since the longwave radiation balance is rarely measured, many computational methods have been designed. In this study, we report on the difference between the observed longwave radiation balance and modelling results obtained using the two main procedures outlined in FAO24 (relying on the measured sunshine duration) and FAO56 (based on the measured solar radiation) manuals. The performance of these equations was evaluated in the April–October period over eight years at the Liz experimental catchment and grass surface in the Bohemian Forest (Czech Republic). The coefficients of both methods, which describe the influence of cloudiness factor and atmospheric emissivity of the air, were calibrated. The Penman-Monteith method was used to calculate the PET. The use of default coefficient values gave errors of 40–100 mm (FAO56) and 0–20 mm (FAO24) for the seasonal PET estimates (the PET was usually overestimated). Parameter calibration decreased the FAO56 error to less than 20 mm per season (FAO24 remained unaffected by the calibration). The FAO56 approach with calibrated coefficients proved to be more suitable for estimation of the longwave radiation balance.

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