No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
A Case Study on Solar Data Collection and Effects of the Sun`s Position in the Sky on Solar Panel Output Characteristics in North Cyprus
Abstract
This paper mainly focuses on methods of calculations of sun`s position in the sky and analyses of its effects on solar panel output characteristics collected during a case study. Methods for calculations of sun`s position in the sky and measurement of solar panel output characteristics are reviewed and then followed by a case study on an experimental data collection system in Northern Cyprus. During the case study, the collected ground measured data are analysed and the results are compared. The solar angle of incidence and the sun`s position in the sky are calculated and compared for different time intervals along with panel output characteristics. The short-term data sets belong to three sample days representing sunny, rainy and cloudy conditions in May-2012. The results highlight the effects of sun`s position in the sky and the incidence angles of sunlight, during different time intervals and dates, on module output characteristics. The results provide helpful information for researchers and system designers for system yield estimation purposes.
... A stationary stripe-shaped target and digital camera have been used in the method presented in [7]. For evaluation of global solar radiation data, different methods have been presented in [8][9][10]. In [11] and [12], experimental methods for evaluation of solar flux and its effect on the performance of the system have been presented. ...
In central tower concentrated solar power plants, the concentrated flux distribution at the receiver is controlled by the aiming strategy of thousands of heliostats in the field to accomplish the specific requirements of solar-thermal conversion processes. The main goal of this work is to evaluate the reflected solar flux from a heliostat or from a group of heliostats on a calibration target. The solar flux map at the target receiver is constructed using the information embedded in a captured high dynamic range image of the evaluated scene. In the present article, a methodology has been proposed to evaluate the optical performance of solar central receiver systems in terms of beam accuracy and optical quality of reflected light on calibration target. The developed system is a simple, automatic and effective tool used to accurately analyse the reflected solar flux without limitations of previous methods, such as using specific type of calibration target. The capability of the present methodology for accurate analysis is demonstrated through experimental indoor and outdoor tests.
... However, a much better prediction performance can be obtained from the optimized LM-ANN (17 neurons) and BR-ANN (11 neurons) with an MSE and R 2 for the testing data set of 0.0014 and 0.9817 (LM-ANN) and 0.0164 and 0.9724 (BR-ANN), respectively. Since the LM algorithm is much simpler than the BR algorithm, 58,59 the optimized number of hidden neurons of LM-ANN (17 neurons) was found to be higher than that of the BR-ANN model (11 neurons). Table 1 summarizes MSE and R 2 as well as the number of hidden neurons of the three optimized ANN models. ...
Solubility of hydrogen sulfide (H2S) in 46 single and blended physical absorbents, amines, ionic liquids, and hybrid absorbents of amines + ionic liquids and amines + physical absorbents was successfully predicted based on artificial neural networks (ANNs). Three neural network algorithms of Levenberg-Marquardt (LM), Bayesian regularization (BR), and scaled conjugate gradient (SCG) were applied for architecting the ANN models. The results showed that both the number of hidden neurons and the prediction algorithm affected the prediction of H2S solubility. Based on the mean square error (MSE) and determination coefficient (R 2), the most attractive model was the LM-ANN model with 17 hidden neurons. As a result, very satisfactory prediction performance (for the testing data set) with an MSE of 0.0014 and an R 2 of 0.9817 was obtained from the developed LM-ANN model. Additionally, a parity chart confirmed that the predicted solubility of H2S well aligned with the experimental data. To effectively absorb H2S and maintain high solubility of H2S, the absorbent should be well complied with the operating pressure. For a low-pressure range of less than 100 kPa, amines are very attractive. As the pressure elevated to 100-1000 kPa, amines and hybrid amine + physical absorbents are suggested. Lastly, at a high pressure over 1000 kPa, physical absorbents and ionic liquids are recommended.
... In [4], a method for estimation of solar radiation on surfaces at different orientations has been presented. For evaluation of global solar radiation data, different methods have been presented in [5][6][7]. In [8], an experimental study for evaluation of solar flux distribution on a flat receiver has been presented. ...
In solar central receiver (SCR) systems, camera-based tracking and control strategies have been widely developed and tested. The camera, usually with a single CCD, captures images of the sun reflected by thousands of heliostats on the central receiver. The captured images are then analysed to allow the evaluation of solar flux. For accurate analysis process, the camera must have a high dynamic range (HDR) to give real and accurate information about the captured scene. In the present article, a new methodology has been developed using a double-CCD optical camera for improvement of dynamic range of the captured solar flux image. An experimental calibration setup is adopted for accurate estimation of the camera response function. The double-CCD camera is used for acquiring two images at the same instant with two different levels of exposure. The two captured images are then merged into a single HDR image using a new proposed weighting function. The enhanced optical performance of the proposed weighting function has been demonstrated by comparison with the previous HDR image generation weighting functions at different levels of illumination. Investigation of the capability of the proposed methodology for the analysis of beam accuracy and optical quality of SCR systems show that the present proposed method leads to more accurate solar flux analysis because of the improvement in the resolution of details of the final merged image.
... and , the inclination coefficient is [27], [28]: ...
The open-air solar drying is a traditional method used for drying Gelidium sesquipedale in Morocco, an important commercial maritime specie of red algae existing in abundant quantities in the large Moroccan coast between Safi and EL jadida. However, this method is not professional and is time-consuming. Here, we present a modified design of a solar air heater destined to use as a component in an indirect solar dryer of Gelidium sesquipedale. We report the results of simulation of the thermal behavior of a modified simple back-pass solar collector in order to predict parameters influencing its thermal performances, such as the number and the diameter of perforations in the configuration, the airflow rate, the solar irradiance. To achieve this, a 3D simulation with finite element model (FEM) is built using the meteorological data collected at the chosen location during the regular harvesting period (July, August and September). The results show that the optimal simulated configuration of a flat plate solar collector is of seven symmetrical perforations of 30 mm diameter, and mass airflow rate around 60kg/h. The best conditions for drying algae are achieved using a solar collector facing south and inclined by 20° to the horizontal. The air outlet temperature will be in the range of 35 to 44°C that is relevant for low temperature drying of seven hours a day, safeguarding the quality of the red algae destined for processing.
The contribution of power production by photovoltaic (PV) systems to the electricity supply is constantly increasing. An efficient use of the fluctuating solar power production will highly benefit from forecast information on the expected power production. This forecast information is necessary for the management of the electricity grids and for solar energy trading. This paper presents an approach to predict regional PV power output based on forecasts up to three days ahead provided by the European Centre for Medium-Range Weather Forecasts (ECMWF). Focus of the paper is the description and evaluation of the approach of irradiance forecasting, which is the basis for PV power prediction. One day-ahead irradiance forecasts for single stations in Germany show a rRMSE of 36%. For regional forecasts, forecast accuracy is increasing in dependency on the size of the region. For the complete area of Germany, the rRMSE amounts to 13%. Besides the forecast accuracy, also the specification of the forecast uncertainty is an important issue for an effective application. We present and evaluate an approach to derive weather specific prediction intervals for irradiance forecasts. The accuracy of PV power prediction is investigated in a case study.
When planning the application of renewable energy sources it is necessary to take decisions not only on the basis of elementary information about these energy sources but also on the basis of more general and more profound knowledge than is currently available. Complex and additional information about the intended application can be obtained from measuring, collecting and analysing relevant data. The present paper describes a system for measuring, collecting, analyzing, and displaying data. A 100 W solar energy converter is used to monitor the effect of operating conditions on its loading characteristics. This photovoltaic (PV) cell and the associated measuring and data acquisition system have been installed in the solar laboratory (on a terraced roof) in the Department of Electrical Power Engineering, FEEC, BUT. Thanks to the system of collecting, archiving, and analyzing the data measured we can monitor, define, and subsequently interpret all positive and more significantly the negative external effects on the efficiency of the device.
A lively and authoritative account of today's photovoltaic (PV) technology and its practical applications This book covers areas including: • a brief history of PV, and the current international scene; • the scientific principles of solar cells including silicon and new thin-film varieties; • PV modules and arrays; • grid-connected PV, from home systems up to large power plants; • the wide diversity of stand-alone PV systems, and; • the economic and environmental aspects of solar electricity. Key equations and numerical examples are fully discussed, providing essential theoretical background. The text is supported by copious illustrations and more than eighty inspiring full colour photographs from around the world to demonstrate PV's huge range of practical applications. This book is aimed at a wide readership including professionals working in related areas, and students taking introductory courses in PV and renewable energy. Its style and level will also appeal to energy planners and decision makers, members of environmental organisations, and the increasing number of people interested in generating their own electricity from sunlight.
We quantify the accuracy of various well-known models of the literature: the seven first type of models calculate diffuse horizontal irradiations from global ones and the fifteen second type models compute global irradiation on inclined planes from diffuse and global components on a horizontal surface. Then, the two classes of models are combined and the adequacy of each association is calculated for experimental hourly data collected on a French Mediterranean site. We compared these combinations with the Olmo model transforming directly global irradiations on tilted planes from horizontal ones.
The photovoltaic geographic information system (PVGIS) is a web-based knowledge distribution system that provides climate data and tools needed for the performance assessment of photovoltaic (PV) technology in Europe. Geodatabases and simulation models are interlinked with the web interface, thus providing easy-to-use access to users. Interactive maps play an important role in understanding the geographic dependency of the performance of the PV technology. While our previous papers dealt with technical aspects of development and data analysis, here we review lessons learned from the feedback of users. A description of the underlying data and web tools is followed by the analysis of two points that are often discussed when comparing PVGIS with alternative systems: 1) the uncertainty of solar radiation estimates and 2) PV yield predictions. For systems based on the ground observations, such as PVGIS, higher uncertainty of estimates can be expected in mountains, close to the coastline, and in regions with lower density of the meteorological stations. A comparison of PVGIS with other simulation software may show regional differences, which typically reflect: 1) the use of underlying databases that are based on diverse input data (ground-measured or satellite with various observation periods) and that vary in spatial and time resolutions, and 2) the use of different simulation concepts. A cross comparison of the existing systems is needed to identify advantages and limits of their use in solar energy projects.
The Spanish Royal Decree 661/2007 for the regulation of renewable energy allows operators of power plants to participate directly on the electricity market instead of reverting to flat-rate prices. The premium tariff option motivates operators of renewable energy plants to increasingly act like managers of conventional plants, selling electricity at the liberalized market. Just like a normal market participant, the operator places bids in advance on the day-ahead market and is obliged to fulfill them. Thus, there is the need for operators of renewable energy plants to be able to provide predictable and dispatchable energy in the profitable premium tariff. This legal setting motivates the following analysis on the value of irradiance forecasts for determining optimal operation strategies of solar power plants. The scientific background of this study are ongoing research activities on the use of satellite-based now casting of solar irradiance using cloud motion vector techniques and on data assimilation of aerosols into air quality models as a basis for day-ahead irradiance forecasts. The influence of a schedule based on imperfect forecasts on the daily revenue for a solar thermal power plant is assessed. Three typical weather situations are analyzed: clear-sky, overcast, and aerosol-charged situations. This paper shows the economic potential of the participation at the premium tariff with optimized operation strategies using direct solar irradiance forecasts based on Earth observation techniques.
Reviews the application of solar energy technology in Cyprus and
presents an energy analysis, including the use of solar energy, in the
island. Cyprus has no conventional sources of energy and is dependent on
imported oil. However, its geographical position is such that it is one
of the countries where the potential for solar energy utilisation is
very high. Cyprus began manufacturing solar water heaters in the early
1960s and produces more than 30000 m2 of solar collectors
yearly. It is estimated that more than 130000 solar water heaters are in
operation, which provide the equivalent of 9% of the total electricity
consumption in the island, and corresponds, approximately, to 4% of the
national energy consumption. However, the use of solar energy for space
heating and cooling provides a further challenge because it does not
appear to be economic under the climatic conditions and system design
practices currently prevailing in Cyprus. The article provides a
statistical analysis of the energy demand and identifies areas of
further growth for solar energy technology
The European Solar RadIatIon Atlas
- K Schamer
- J Greif