Amount Of Solar Radiation Research Articles

Simulation of regional climate models of total cloud fraction in Morocco for the period of 2020-2050

The Moroccan energy system is highly dependent on external energy markets. The use of solar energy is one of the most promising ways in the development of renewable energy sources. At the moment, there are several scenarios for the development of renewable energy in Morocco diverging only in quantitative assessments. All of them are aimed at increasing the generation of green energy, from the complete satisfaction of all needs of Moroccan consumers to the opportunity of exporting some of its environmentally friendly electricity to Europe. Estimation of energy efficiency of solar installations is usually carried out on the basis of calculations of solar radiation arrival in the presence of cloudless sky. Clouds significantly reduce amount of solar radiation and sunshine duration. This study is aimed at determination of possible quantitative parameters of the total cloud cover and the areas in which the cloud cover would have the least impact on the amount of incoming solar radiation in Morocco in 2020-2050. The article presents the results of simulation of total cloud fraction using 11 regional climate models of CORDEX project for the period of 2020-2050 in Morocco. For the period of 2020-2050 the average values of total cloud fraction on the territory of Morocco will have the smallest values within the plains located near the border with Algeria on the territory of the prefecture of Sous-Massa lying at the foot of the southern slopes of the Anti-Atlas. The analysis of the annual regime of total cloud fraction showed that in the future it will be of a different nature in different parts of the country due to various factors affecting its formation. The area with the smallest volumes of monthly total cloud fraction will lie within the territory the southern part of prefecture Draa-Tafilalet and prefectures Sous-Massa, Guelmim-Oued Noun, Laayoune-Sakia El Hamra, Dakhla-Oued Ed-Dahab excluding their coastal parts of the Atlantic Ocean.
 In the future most of the territory of Morocco will be characterized by a low amount of total cloud fraction, which, in its turn, will have an insignificant effect on the amount of solar radiation entering to the underlying surface of these areas. In terms of solar power, the best conditions will exist at the southern parts of Morocco, excluding the coast where the total cloud fraction will have the least impact on the amount of solar radiation reaching the earth’s surface and on sunshine duration.

Determination of optimum tilt angle and orientation for solar collectors based on effective solar heat collection

Determination of optimum tilt angle and orientation of solar collectors by maximizing the total solar radiation may overestimate the energy production benefits, because a considerable amount of solar radiation is ineffective for practical solar collectors. In this paper, the concept of effective solar heat collection is proposed to rule out the ineffective solar radiation that could not be converted to available energy. Accordingly, an optimized mathematical model is developed and used to determine the optimum tilt angle and orientation of solar collectors installed in Lhasa during the heating season. Compared with the total solar radiation based optimum results, there is a deviation of 5° in the optimum orientations based on the effective solar heat collection. The case study shows that it is not advisable to adjust the optimum tilt angle on a monthly basis because there is no significance change in total solar energy gains in comparison with the case of no such adjustment during the heating season. In addition, the correction factors to achieving the maximum effective solar heat collection are given at different tilt angles and orientations to guide installation of solar collectors in practical engineering applications.

Solar radiation strongly influences the quantity of forest tree root exudates

The quantity of root exudate carbon produced by Quercus crispula Blume was strongly influenced by the amount of solar radiation 1 day before collection. We aimed to investigate seasonality in the quantity of root exudate produced, and the factors affecting exudate quantity, in mature Quercus crispula Blume trees throughout the growing season. We also aimed to understand the timespan of exudation, from production of photosynthate to release as exudate. We measured the amount of root exudate C produced by Q. crispula, as well as environmental factors including solar radiation and soil and air temperature throughout the growing season. The model best explaining the amount of exudate C, based on the lowest Akaike’s information criterion, was selected to determine the environmental factors that affect exudation. The quantity of exudates did not show clear seasonality, and instead varied widely among sampling dates. A regression model with daily solar radiation for 1 day before sample collection as the sole factor affecting the quantity of exudates was selected as the best model. Solar radiation, which fluctuated greatly among days, more strongly affected the quantity of exudates produced than factors that fluctuated seasonally, such as average temperature. Furthermore, most root exudates from Q. crispula are released within 1 day of being generated by photosynthesis, rather than over several days.

UAV Capability to Detect and Interpret Solar Radiation as a Potential Replacement Method to Hemispherical Photography

Solar radiation is one of the most significant environmental factors that regulates the rate of photosynthesis, and consequently, growth. Light intensity in the forest can vary both spatially and temporally, so precise assessment of canopy and potential solar radiation can significantly influence the success of forest management actions, for example, the establishment of natural regeneration. In this case study, we investigated the possibilities and perspectives of close-range photogrammetric approaches for modeling the amount of potential direct and diffuse solar radiation during the growing seasons (spring–summer), by comparing the performance of low-cost Unmanned Aerial Vehicle (UAV) RGB imagery vs. Hemispherical Photography (HP). Characterization of the solar environment based on hemispherical photography has already been widely used in botany and ecology for a few decades, while the UAV method is relatively new. Also, we compared the importance of several components of potential solar irradiation and their impact on the regeneration of Pinus sylvestris L. For this purpose, a circular fisheye objective was used to obtain hemispherical images to assess sky openness and direct/diffuse photosynthetically active flux density under canopy average for the growing season. Concerning the UAV, a Canopy Height Model (CHM) was constructed based on Structure from Motion (SfM) algorithms using Photoscan professional. Different layers such as potential direct and diffuse radiation, direct duration, etc., were extracted from CHM using ArcGIS 10.3.1 (Esri: California, CA, USA). A zonal statistics tool was used in order to extract the digital data in tree positions and, subsequently, the correlation between potential solar radiation layers and the number of seedlings was evaluated. The results of this study showed that there is a high relation between the two used approaches (HP and UAV) with R2 = 0.74. Finally, potential diffuse solar radiation derived from both methods had the highest significant relation (−8.06% bias) and highest impact in the modeling of pine regeneration.

Thermal analysis of building roof assisted with water heater and insulation material

Traditional roof systems are constructed with concrete and weathering coarse layer and these roof systems absorb and reflect a certain amount of solar radiation. The absorbed solar energy is transferred into building indoor and causes significant discomfort to the occupants. Also, this solar energy gets dissipated without any useful energy conversion. Hence this paper is focused to use the available solar energy effectively through a novel solar water heating system and the transfer of heat in the building indoor is arrested by proper roof insulation material. The modified insulated roof with the solar water heater is designed and simulated numerically in commercial computational fluid dynamics code with validation. Through this study, the factors that affect the performance of solar water heating system and thermal insulation capacity are analysed and the best design of the modified roof system is identified. The modified roof system produces 25 L of hot water per day with a temperature raise of 60°C in the winter season. Also, the same roof system maintains the ceiling temperature at about 27°C for a complete day in a summer season.

COMPARATIVE STUDY OF THE OPTICAL PROPERTIES EFFECT OF THE FACADE EXTERIOR COATING ON THE BUILDING ENERGY DEMAND

There are different technologies to optimize the use of solar energy in construction systems, with the aim of improving the building energy efficiency and also to reduce the effect of solar radiation on the exterior coatings, which in turn affects the urban areas warming. Among these technologies, chromogenic devices based on materials whose optical properties can be reversibly modified by some external stimulus have become relevant. These materials are especially interesting because they adapt to variations of solar radiation during the day and throughout the different seasons of the year. The facade coating may have different types of texture or color, which determine specific optical properties. One of these properties is the absorptance, which determines the amount of solar radiation absorbed by the material with respect to the incident radiation. The effect of the absorptance on the building energy demand will be conditioned by other parameters that also influence it, such as the climatic zone, orientation and thermal properties of the wall. In the work presented, the influence of the optical properties of three types of exterior facade coating on the building energy demand is analyzed. The materials chosen for this study are a conventional white Portland cement, a belitic cement synthesized in the laboratory by a process of low energy and low CO2 emissions and a brick representative of a brickwork wall, presenting the first two a more polished finish and clearer colors than the second. The final objective of this study is to determine the parameters that optimize the utilization of the optical properties of the studied coatings in the building energy efficiency.

Energy Efficiency of Low Quality Built Heritage: Methodological Reflections on Achieving the NZEB through a Case Study in the City of L'Aquila

About the building heritage and, in particular, about the widespread heritage without historical or architectural quality, it currently opens a challenge in perpetual evolution. This is the integration of innovative technological solutions for building regeneration, which can help a qualitative improvement of the living spaces and the reduction of energy consumptions. Context factors, the intensity of precipitation, the different types of soil, and the amount of solar irradiation or wind speed are doubtless the main causes of the degradation of the existing buildings. On another way, through the control of climatic and biophysical parameters, the focus on the properties of materials and a careful design process, these variables can increase the use of renewable energy sources, becoming environmental resources to reduce energy consumption, to provide comfortable living spaces and aiming the realization of a Near Zero Energy Building. The paper proposes a reflection on the main methodological issues emerged in the hypothesis of intervention experimented on a case study in the city of L'Aquila. The building, located near the historical center of the city, is in direct relation with important pre-existences such as the Forte Spagnolo and the San Salvatore hospital. It is an example of possible regeneration of low quality building in which the additional use of new functional spaces can increase not only energy performances, but also an increase of architectural value of the building.

공동주택 수직 벽체 설치 BIPV 시스템의 발전량 예측 프로그램 개발 연구

Purpose: The installation of the BIPV system in the apartment complex is expected to increase significantly in the future. However, due to the characteristics of the apartment complex, it is very likely that the building will be shaded by neighboring buildings. Therefore, it is difficult to judge the efficiency of the installed BIPV system by simple judgment method. In order to expand the application of the BIPV system, a practical evaluation method for the annual Duration of Sunshine and the generation amount of the wall that BIPV panel will be applied, so that accurate economic judgment and optimization of the installation location are required. The purpose of this study is to develop a program that can effectively evaluate the annual Duration of Sunshine and the generation amount for the application location of the BIPV system installed on the vertical exterior wall of apartment. Method: In this study, a program was developed to evaluate the annual duration of sunshine, flux of solar radiation, and generation amount, which reflects the effects of obstruction on the BIPV installation site in the apartment complex. The method of evaluating the flux of solar radiation and generation amount of the developed program was verified by comparing measured data with prediction result. The evaluation program is designed to perform calculations in conjunction with commercial CAD programs, so that it is possible to easily evaluate the generation amount according to the installation location of BIPV without any special knowledge or program management training.Result: In addition, it is confirmed that more realistic generation amount can be calculated by using possible performance parameters that can be referenced in the PV performance test report.

How light absorbing properties of organic aerosol modify the Asian summer monsoon rainfall?

Light absorbing aerosols not only contribute to Earth's radiative balance but also influence regional climate by cooling the surface and warming the atmosphere. Following recent suggestions that organic aerosols (OAs) absorb substantial amount of solar radiation, we examine the role of light absorbing properties of OA on Asian summer monsoon rainfall redistribution using observational data and an atmospheric general circulation model (AGCM) experiment. Results suggest that the enhanced light absorption by OA in Southeast Asia and Northeast Asia are associated with the advance of the Indian summer monsoon in May and the southward shift of East Asian summer monsoon rain band in June. The rainfall redistribution in May is induced by elevated orographic effect with a warm-core upper-level anticyclone and surface warming of 1-2°C over the Tibetan Plateau whereas that of the East Asian summer monsoon in June is formed by stable conditions associated with surface cooling and atmospheric warming around 30°N.

Investigating the impact of feature selection on the prediction of solar radiation in different locations in Saudi Arabia

Predictions about the future amount of solar radiation is an important factor that affects the planning and operating of solar energy projects. However, it is a difficult task due to the existence of a high level of uncertainty that is associated with unknown future weather conditions. Accordingly, the prediction process, especially for the short term, requires more attention to unveil hidden relationships and interactions between related variables. Since a large number of parameters affect the estimation and prediction processes, there is a need to apply an effective and efficient feature selection of the input feature space. In this paper, an investigation of different feature selection methods is carried out in order to predict the daily amounts of solar radiation in different locations in Saudi Arabia using a neural networks (NN) predictor. First, the selection of the most important variables is carried out using four different algorithms: ReliefF algorithm, Monte Carlo uninformative variable elimination algorithm (MCUVE), random-frog algorithm, and Laplacian score algorithm (LS). Then, a computational intelligence model of a multi-layer neural network is used as the predictor. The predictor aims to predict the next-day global horizontal irradiance using selected meteorological and solar radiation observations. The experimentation and results of the feature selection methods and the prediction process are described. The results showed the importance of using feature selection methods in order to obtain a reliable prediction of the amount of solar radiation compared with using all the features available.

FACTORS AFFECTING PHENOLOGY OF DIFFERENT Citrus VARIETIES UNDER THE TEMPERATE CLIMATE CONDITIONS OF SANTA FE, ARGENTINA

ABSTRACT The aim of this study was to characterize the phenology of different sweet orange, tangerines and tangerine hybrid varieties growing under the temperate climate conditions of Santa Fe Province, Argentina. Phenological stages were observed weekly during five consecutive years using a BBCH (Biologische Bundesanstalt, Bundessortenamt and Chemical industry) scale adapted for Citrus trees. All varieties showed a winter rest period from June to August. ‘New Hall’ and ‘Navelina’ varieties were the first to reach sprouting stage, whereas ‘Okitsu’ was the last. Inception of flowering occurred from August 13th to September 6th; and full bloom from September 12th to October 2nd. Fruit harvest started with the ‘Okitsu’ cultivar in March, and continued over a 7-month period. Interannual variation for inception of sprouting was high (44 days), and sprouting was correlated with both thermal accumulation (above 13ºC) and the amount of solar radiation measured during July (p<0.0001; r2=0.79). Navel oranges and the ‘Murcott’ hybrid bloomed 5–15 days earlier than other varieties, increasing probability of damage by late frosts.

Periodic urban models for optimization of passive solar irradiation

Urban sprawl and energy consumption issues suggest to consider how to design energy efficient dense cities. Solar radiation is a significant heat input in well insulated buildings in temperate climates. However, the solar masks generated by the surrounding buildings in dense urban areas can reduce significantly this energy gain. This paper proposes a definition of a district as a periodic urban fabric, where a given configuration of buildings, called urban cell, is repeated to represent the urban outline. It allows us to evaluate the relationship between cumulative solar potential on façades and urban shape, with solar masks that are consistent with the considered area. In this study, an evolutionary algorithm is used to explore the set of urban cells composed of a square grid of blocks of varying height. Four conditions for solar radiation are taken into account: clear sky direct radiation at the latitude of 50° North for three particular days (winter solstice, summer solstice and equinox), and annual direct and diffuse radiation based on the meteorological data of Paris, France. For each condition of solar radiation, the influence on the optimization results of the size of the area of interest and its built density is assessed. The results provide information on what are the urban shapes maximizing solar potential and give some quantitative indications on the amount of solar radiation that can be captured.

Solar water heaters as a pre-heating system for industrial processes

Although solar heating for hot-water production is a mature technology, the general public’s knowledge is mostly confined to domestic uses such as cleaning and washing. In the industrial sector, there is a demand for thermal energy of lower than 250 °C, but to develop applications for industrial heat processes, real energy savings are one of the key issues determining customers’ choice of energy. However, the solar gain from solar water heaters based on the lab tests may be misleading, so field measurements are important to evaluate a system’s financial viability. This study presents 1 year of field measurements for solar water heaters installed as the pre-heating system in a poultry slaughterhouse. The system efficiency is compared with that installed in a dormitory, where the hot-water consumption pattern is similar to that in the domestic sector. These results demonstrate that the amount of global solar radiation and hot-water consumption patterns have a significant effect on the system’s efficiency. A simple cost-to-benefit analysis is also presented based on this real application for solar water heaters.

Photovoltaic installation for a roofed car park in Egypt as an example of effective use of solar energy

Photovoltaic installations are becoming an increasingly important player in the global renewable energy production market. The biggest disadvantage of photovoltaic installations is their high price, and relatively low efficiency. Photovoltaic cells achieve a theoretical efficiency of 30%, but in real conditions this efficiency is much lower at roughly 15%. Photovoltaic installations are particularly recommended in locations where the amount of solar radiation is high and where photovoltaic installations will be able to work at full capacity for most of the year. The paper presents an analysis of the work of a photovoltaic installation built for a roofed car park located in eastern Cairo, the capital of Egypt. The installation is built for a car park located at the Schlumberger company. The installation is built of 1344 Hanwha Q.Power L-G325 silicon polycrystalline cell modules, each module has a power of 325 Wp, and the total area of the installation is 2,611 m2. Effective irradiance on collectors is 1922 kWh/m2. The array’s nominal produced energy was 840 MWh/year, the amount of electricity injected into the grid was 587 MWh/year, which means that the calculated performance ratio was 0.62.

Optimizing the control system of a single-axis sun tracking mechanism

The work shows the optimization of the control system for the single-axis solar tracker that equips a solar panel, with the aim to increase the energetic efficiency of the system by maximizing the quantity of incident solar radiation that is captured - absorbed by the panel. The single-axis solar tracker is driven by a linear actuator, the optimization study intending to determine the optimal configuration (in terms of tuning factors) of the controller, which is a PID (Proportional-Integral-Derivative) device, in order to accurately achieve the motion (tracking) law imposed on the solar panel. The solar tracker was approached as a mechatronic system, the mechanical device (developed in ADAMS - Automatic Dynamic Analysis of Mechanical Systems) and the control system (developed in EASY5 - Engineering Analysis System) being integrated at the level of virtual prototype, in the concurrent engineering concept.

Wavelet Analysis of Atmospheric Aerosols as Ambient Air Pollutants

Atmospheric aerosols, also known as atmospheric particulate matter or suspended particulate matter (SPM), are microscopic solid or liquid matter suspended in Earth's atmosphere that are transported and dispersed in the atmosphere. Study of atmospheric aerosols as ambient air pollutants has attracted the great interest of scientists due to the effect on human health and its major role in climate change. Reduced lung function, development in respiratory diseases and premature death are the effect of long-term exposure to ambient air pollution. The atmospheric aerosols affect the climate of the earth by changing the amount of incoming solar radiation and outgoing terrestrial long wave radiation retained in the earth's system and their climate effects are the biggest source of uncertainty in future climate predictions. Wavelet transforms provide excellent analysis of non-stationary time series and extracts important hidden information from a signal or data set. For the data set of SPM and RSPM of Moradabad for given time interval, Haar wavelet transform of Level1 is applied. Skewness and Kurtosis parameter describes the lack of the symmetry of data and correlation coefficient between SPM and RSPM describes the linear relationship between them.

Optimize the Energy Conversion Efficiency for Solar PV Grid-Connected System at Low Distribution Voltage

Renewable energy found in many forms such as solar and wind energy, tidal energy, etc. In this work, we interested to focus on solar power because of it is clean and the large amount of solar radiation arrived to the surface earth. The main purpose of this article aims to maximize the amount of extracted power from the solar system. This research investigates the connotation of maximum power point tracking (MPPT) methods which significantly increases the efficiency of the solar photovoltaic (PV) energy system. This paper presents a simulation based comparison between two different MPPT methods to optimize the energy conversion efficiency of solar PV system.

The combined effect of nanofluid and reflective mirrors on the performance of PV/thermal solar collector

A photovoltaic/thermal solar collector is a system which is capable of producing both electricity and thermal energy. However, this technology still needs more studies. In this paper, a mathematical model was presented to study the perfor¬mance of a photovoltaic/thermal collector by using the upper and lower reflectors with the presence of glass cover. Water and nanofluids (AL2O3-H2O) were used as cooling medium. A computer program was proposed to calculate the amount of solar radiation reflected on the reflected mirrors and then absorbed by the hybrid collector and study the effect of nanofluid on the performance of the system. Solar radiation absorbed by the collector can be increased using the upper and lower reflectors to 1138 W/m2 while it can reach 950 W/m2 with the upper reflector and 746 W/m2 with the lower reflector. It was noticed that when using reflective mirrors, the outlet water temperature increased by 21.7%. Meanwhile, the outlet water temperature increased by 0.44% when nanofluid was used as a cooling me¬dium. The average of daily thermal efficiency as a result of using two reflectors without nanofluid was 62.1%, while the thermal efficiency was 59.735% without using any reflector, meaning a positive effect of using reflectors on the thermal efficiency. The electrical efficiency reduced with the existence of the reflective mirrors, whereas the daily average of the total electrical efficiency without the reflective mirror and using the nanofluid was (14.6%), while with a reflective mirror and using nanofluid, the daily average was (13.67%).

Evaluation of the Best Slope Angle for a Flat-Plate Solar Collector

The performance of flat plate solar collector is affected by the value of its slope angle with respect to horizontal plane, where the variation of slope angle changes the amount of incident solar radiation. So, using the solar tracking system for solar collector will get the maximum solar radiation, the application of the solar tracking system cost has high operation and maintenance. It is usually suitable to set the solar collector at a best fixed slope angle throughout the year with less reduction in solar radiation received on the collector surface. In this work, a best slope angles were calculated for solar collectors based on the monthly mean daily solar radiations on a horizontal surface over some Iraqi cities (Mosul, Rutba, and Basra). The total of rays flux incident upon a solar collector is mainly affected by the installation angle. The solar collector can be oriented at three different angle settings. The first angle setting is to adjust the collector monthly off to give highest incident solar radiation, while the second angle setting suggests the seasonally changes (Winter, Spring, Summer, Autumn) .The final adjustment for solar collector can be achieved using the mean value for the four seasons to get yearly averaged throughout the year

RECEIVER TEMPERATURE MAPS OF PARABOLIC COLLECTOR USED FOR SOLAR FOOD COOKING APPLICATION IN ALGERIA

Limited fossil resources and environmental problems imply that development of solar thermal appliances will play major role in incoming years, especially to meeting domestic energy requirements. The cooking energy demand, which is the largest primary energy-consuming sector and, are continuously increasing. This research paper deal with the temperatures and efficiency mapping of a realized parabolic solar cooker tested in Saharan region of Ghardaîa (Algeria) climatic conditions. Using Black body temperature equation’s based on Stefan-Boltzmann law, maps for focal areas receiver temperatures of the cooker are obtained by converting obtained results from optical simulation to thermal values. Several maps are generated through present study for both summer and winter with clear and cloud skies. It was found that cooker temperature values obtained during experimentations and that estimated using the proposed approach has good agreement. The rate of using the cooker from Northern to Southern regions of the country was not identical. For cloudy skies, the major area of the country is favorable for the use of the cooker during winter months. For clear skies, the mapping results indicate that the realized cooker is efficient in all the country throughout the summer season with temperatures exceeding 110 °C. The use of the cooker will be reduced by going in South to North regions during the winter months, depending on the amount of solar radiations received.