Article

Quantifying the decrease of the photovoltaic panels’ energy yield due to phenomena of natural air pollution disposal

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Photovoltaic (PV) applications, gaining worldwide interest during the last years, comprise a promising renewable energy based solution, able to considerably contribute to the constantly increasing energy demand of our planet. Currently, residential applications possess a considerable share of the global PV market since fiscal and practical incentives have reinforced their promotion. On the other hand, high population concentration, rapid industrialisation and economic development of urban areas all over the world have caused significant degradation of the urban air quality. In this context, the actual performance of five identical pairs of roof-top PV-panels, operating in the aggravated urban environment of Athens (from the atmospheric air pollution point of view), is currently evaluated. For this purpose, a series of systematic experimental measurements is conducted within a certain time period and the influence of different dust deposition densities on the energy yield and the economic performance of the small power station is estimated. According to the results obtained, the presence of dust considerably affects the PV-panels’ performance since even a relatively small dust deposition density (≈1 g/m2) may result in remarkable energy losses corresponding almost to 40 €/kWp on an annual basis.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... This may be because the dust natural accumulation is, not a global issue but, a site-dependence process. Few studies [11] and [14][15][16][17][18][19][20][21][22][23][24] investigated this effect and the consequent efficiency degradation. A village near Riyadh, KSA is using a solar PV system was considered as one of the excellent sites to study this phenomenon. ...
... Over a period of two month an experimental study was carried out (i.e. August-September 2009) in order to quantify the effect of urban air pollution on the energy performance of PV panels [23]. Kaldellis et al. [23] experiment was conducted in Athens, Greece. ...
... August-September 2009) in order to quantify the effect of urban air pollution on the energy performance of PV panels [23]. Kaldellis et al. [23] experiment was conducted in Athens, Greece. According to the results obtained, up to nearly 6.5% was a reduction of the PV-panels' energy production in comparison with a clean panel [22]. ...
... However, it has not been until the last 10 years when the number of publications about the different mechanisms of degradation, which affect the behaviour of PV modules [25][26][27], have significantly increased, as it is shown in Fig. 3. The importance of the research of the different degradation mechanisms resides in the reduction in the amount of solar radiation that PV modules can transform into energy, causing both energy and economic losses [28]. For this reason, the analysis of the effects of degradation and the development of preventive techniques should be conducted. ...
... As commented, the main consequence of soiling is the reduction of the energy generated by PV modules [28]. The amount of energy losses due to soiling shows a strong correlation with the accumulated dust density [70][71][72][73] and with some properties of dust, such as chemical composition and size distribution [74]. ...
Preprint
Full-text available
The exponential growth of global capacity along with a reduction in manufacturing costs in the last two decades has caused photovoltaic (PV) energy technology to reach a high maturity level. As a consequence, currently, researchers from all over the world are making great efforts to analyse how different types of degradation impact this technology. This study provides a detailed review of the impact of different optical degradation mechanisms, which mainly affect the transmittance of the top-sheet encapsulant, on the spectral response of the PV modules. The impact on the spectral performance of PV modules is evaluated by considering the variations of the short-circuit current since this is the most widely used parameter to study the spectral impact in outdoors. Some of the most common types of optical degradation affecting the performance of PV modules worldwide, such as discoloration, delamination, aging and soiling have been addressed. Due to the widely documented impact of soiling on the spectral response of modules, this mechanism has been specially highlighted in this study. On the other hand, most of the publications analysed in this review report optical degradation in PV modules with polymeric encapsulant materials. Furthermore, an innovative procedure to quantify the spectral impact of degradation on PV devices is presented. This has been used to analyse the impact of two particular cases of degradation due to soiling and discoloration on the spectral response of different PV technologies.
... Several studies suggested that irradiance is the most influential factor compared to others (Cañete, Carretero, and Sidrach-de-Cardona 2014; Kaldellis and Kokala 2010). This is supported by a study conducted in Korea for building integrated photovoltaic project (BIPV) (Yoo 2011), where the results showed that higher output power measurements are associated with higher solar irradiance levels. ...
... This is supported by a study conducted in Korea for building integrated photovoltaic project (BIPV) (Yoo 2011), where the results showed that higher output power measurements are associated with higher solar irradiance levels. Yet, dust and dirt can cause a remarkable reduction in the efficiency of PV panels up to 15% for BIPV (Kaldellis and Kokala 2010). To the authors' best knowledge, there are few studies attempted at measuring losses due to dust as a function of irradiance. ...
Article
Full-text available
Photovoltaic systems (PV) have been extensively used worldwide as a reliable and effective renewable energy resource due to their environmental and economic merits. However, PV systems are prone to several environmental and weather conditions that impact their performance. Amongst these conditions is dust accumulation, which has a significant adversative impact on the solar cells’ performance, especially in hot and arid regions. This study provides a comprehensive review of 278 articles focused on the impact of dust on PV panels’ performance along with other associated environmental factors, such as temperature, humidity, and wind speed. The review highlights the importance of modelling dust accumulation along with other ecological factors due to their interactive nature, and the differences between cleaning techniques and schedules effectiveness. Moreover, the study provides a review of statistical and artificial intelligence models used to predict PV performance and its prediction accuracies in terms of data size and complexity. Finally, the study draws attention to several research gaps that warrant further investigation. Among these gaps is the need for proper dynamic optimisation models for cleaning schedules and a more advanced machine and deep learning models to predict dust accumulation while considering environmental and ageing factors.
... In this sense, soiling effects can cause power losses up to 70% in the worst scenarios [1]. Bearing this in mind, several studies have investigated the causes of soiling and their relationships with the environmental parameters [2,3,4,5]. Other studies have also pointed out that the attenuation and the scattering phenomena produced by soiling present a clear wavelength dependence [6,7]. ...
... The SRatio, as defined in equations (1), (2) and (3), expresses the effects of both the broadband attenuation and the spectral variation of the irradiance profile produced by soiling. The broadband attenuation considers the average reduction of the light intensity in the absorption band of the MJ cell, while the spectral effects are due to the non-flat spectral transmittance profile of soiling as a function of wavelength. ...
Preprint
Full-text available
Soiling, which consists of dust, dirt and particles accumulated on the surface of conventional or concentrator photovoltaic modules, absorbs, scatters, and reflects part of the incoming sunlight. Therefore, it reduces the amount of energy converted by the semiconductor solar cells. This work focuses on the effect of soiling on the spectral performance of multi-junction (MJ) cells, widely used in concentrator photovoltaic (CPV) applications. Novel indexes, useful to quantify the spectral impact of soiling are introduced, and their meanings are discussed. The results of a one-year experimental investigation conducted in Spain are presented and are used to discuss how soiling impacts each of the subcells of a MJ cell, as well as the cell current-matching. Results show that soiling affects the current balance among the junctions, i.e. the transmittance losses have found to be around 4% higher in the top than in the middle subcell. The spectral nature of soiling has demonstrated to increase the annual spectral losses of around 2%. Ideal conditions for the mitigation of soiling are also discussed and found to be in blue-rich environments, where the higher light intensity at the shorter wavelengths can limit the impact of soiling on the overall production of the CPV system.
... These findings converge-on average-with the general trends resulting from the proposed method ( Figure 17). Furthermore, the effect of heavy soiling is another important factor that may decrease energy production by up to 6.5% on an annual basis [49]. Heavy soiling was observed during the spring of 2019 in Central Greece which resulted in an average decrease of 5.6% [27] in energy generation. ...
... with the general trends resulting from the proposed method ( Figure 17). Furthermore, the effect of heavy soiling is another important factor that may decrease energy production by up to 6.5% on an annual basis [49]. Heavy soiling was observed during the spring of 2019 in Central Greece which resulted in an average decrease of 5.6% [27] in energy generation. ...
Article
Full-text available
Increased penetration of grid-connected PV systems in modern electricity networks induces uncertainty factors to be considered from several different viewpoints, including the system’s protection and management. Accurate short-term prediction of a grid-connected PV park’s output is essential for optimal grid control and grid resilience. Out of the numerous types of models employed to this end during the last decade, artificial neural networks, (ANNs) have proven capable of handling the uncertainty issues of solar radiation. Insolation and ambient, or panel temperature, are most commonly employed as the independent variables, and the system’s output power is successfully predicted within 3 to 5% error. In this paper, we apply a common type of ANN for the long-term prediction of a 100 kWp grid-connected PV park’s output, by exploiting experimental data from the last 8 years of operation. Solar radiation and backsheet temperature were utilized for the ANN training stage. The performance metrics of this model, along with a standard linear regression model, are compared against the actual performance data. The capabilities of the ANN model are exploited in the effort to decouple the fluctuating effect of PV panel soiling which interferes with the efficiency degradation process. The proposed methodology aimed to quantify degradation effects and is additionally employed as a fault diagnosis tool in long-term analysis.
... It is a common phenomenon that is prevalent everywhere in the world. Numerous performance analysis conducted have attributed PV-system power loss to dust deposition on the panels [50,51]. Studies on the effect of dust on the performance of PV-systems showed that dust with a density as small as 1g/m 2 may cause a significant loss in energy output by large amounts of V/kW p annually [52]. ...
... In [10], an installed PV-system generated a small amount of electric energy due to the poor design methods used for computing the correct angle of inclination. In another study, scholars concluded that, for an optimal performance, the angle of inclination should be very close to the angle of latitude of that location [51]. Other researchers have stated that poor PV-system performance often results from the incorrect selection of the solar irradiance measurement parameters to use [55]. ...
Article
Full-text available
Climate change and global warming have triggered a global increase in the use of renewable energy for various purposes. In recent years, the photovoltaic (PV)-system has become one of the most popular renewable energy technologies that captures solar energy for different applications. Despite its popularity, its adoption is still facing enormous challenges, especially in developing countries. Experience from research and practice has revealed that installed PV-systems significantly underperform. This has been one of the major barriers to PV-system adoption, yet it has received very little attention. The poor performance of installed PV-systems means they do not generate the required electric energy output they have been designed to produce. Performance assessment parameters such as performance yields and performance ratio (PR) help to provide mathematical accounts of the expected energy output of PV-systems. Many reasons have been advanced for the disparity in the performance of PV-systems. This study aims to analyze the factors that affect the performance of installed PV-systems, such as geographical location, solar irradiance, dust, and shading. Other factors such as multiplicity of PV-system components in the market and the complexity of the permutations of these components, their types, efficiencies, and their different performance indicators are poorly understood, thus making it difficult to optimize the efficiency of the system as a whole. Furthermore, mathematical computations are presented to prove that the different design methods often used for the design of PV-systems lead to results with significant differences due to different assumptions often made early on. The methods for the design of PV-systems are critically appraised. There is a paucity of literature about the different methods of designing PV-systems, their disparities, and the outcomes of each method. The rationale behind this review is to analyze the variations in designs and offer far-reaching recommendations for future studies so that researchers can come up with more standardized design approaches.
... The decrease in power produced by a PV system due to soiling as a function of exposure time is reported in the literature (Elminir et al., 2006;Mohandes et al., 2010;Kaldellis and Kokala, 2010;Said et al., 2015;Mohamed and Hasan, 2012;Adinoyi and Said, 2013). These studies have shown that this reduction can be up to 50% or less than 2.50% and that the considerable variations in the performance of PV modules depend on the exposure time. ...
Article
Solar energy as abundant energy can easily be converted to electricity using the different solar energy technologies. However, the conversion efficiency is highly affected by many factors such soiling phenomenon. This refers to the accumulation of dust particles and other contaminants on the front surface of the system which prevent the sunlight from reaching the cells or the collectors. The present work is mainly focusing on understanding this phenomenon especially for photovoltaic modules. It represents an updated survey on soiling process and its methods of quantitation based on measuring deposited dust, transmittance or by evaluating the real response of the photovoltaic module. It includes as well the different factors influencing soiling, which have been categorized into five categories related to the module characteristics, the surrounding environment, the climatic conditions, the exposure conditions and the soiling properties. The different methods to mitigate its effect mainly natural, manual, mechanical and self-cleaning have been also discussed. It presents as well a summary of the key contributions on this phenomenon in both countries Morocco and India. This will be as a paved guide to help readers to better understand soiling phenomenon and also to get a clear idea about the trend of research in both countries Morocco and India.
... In Athens, the capital city of Greece, Kaldellis, and Kokala examined the impact of dust on a fixed system with a tilt of 30 degrees. The key finding of the research work was that the output power reduced by 6.5% in a period of eight weeks [40]. The comparison of the current study with other research work is represnted in Table 3. ...
Article
Full-text available
Dust is one of the significant constraints in utilizing solar photovoltaic systems under harsh weather conditions in the desert regions due to creating a shadow that blocks solar irradiance from reaching solar cells and consequently, significantly reducing their efficiency. In this research, experimental study was performed to comprehend the nature of dust particles and their impact on the electrical power output that is generated from azimuth tracking solar PV modules under Sharjah environmental conditions in winter season. According to laboratory experiments, the power losses are linearly related to the dust accumulated density on the surface of the solar panel with a slope of 1.27% per g/m2. The conducted Outdoor studies revealed that the absolute reduction in output power increased by 8.46% after 41 continuous days with one low-intensity rainy day. The linear relationship obtained from indoor experiments was applied later to estimate the dust deposited density on the outdoor setup. The results showed that a regular cleaning process every two weeks is recommended to maintain the performance and to avoid the soiling loss. This work will help engineers in the solar PV plants to forecast the dust impact and figure out the regularity of the cleaning process in case of single axis tracking systems.
... Although this study was carried out in the Atacama Desert (Chile), many other emplacements for the installation of PV plants which are suitable from the point of view of insolation levels can present similar atmospheric conditions. This is the case at coastal sites, such as those in Mediterranean regions or North African countries, for instance, where the humidity and hygroscopic aerosols can stimulate the formation of thick soiling layers, causing the PV cover to become almost opaque [19][20][21][22]. ...
Article
Full-text available
Atmospheric factors, such as clouds, wind, dust, or aerosols, play an important role in the power generation of photovoltaic (PV) plants. Among these factors, soiling has been revealed as one of the most relevant causes diminishing the PV yield, mainly in arid zones or deserts. The effect of soiling on the PV performance can be analyzed by means of I–V curves measured simultaneously on two PV panels: one soiled and the other clean. To this end, two I–V tracers, or one I–V tracer along with a multiplexer, are needed. Unfortunately, these options are usually expensive, and only one I–V tracer is typically available at the site of interest. In this work, the design of a low-cost multiplexer is described. The multiplexer is controlled by a low-cost single-board microcontroller manufactured by ArduinoTM, and is capable of managing several pairs of PV panels almost simultaneously. The multiplexer can be installed outdoors, in contrast to many commercial I–V tracers or multiplexers. This advantage allows the soiling effect to be monitored on two PV panels, by means of I–V indoor tracers. I–V curves measured by the low-cost multiplexer are also presented, and preliminary results are analyzed.
... A plot (Fig. 7) Fig. 7 Curves of plotting a P in versus T, b P ec versus T, c P th versus T, d P loss versus T and e P over versus T based on the data monitored from the panel of PV cooled with the water flow rates of (i) 12 L h -1 , (ii) 18 L h -1 and (iii) 24 L h -1 varied largely depending on the rate of water flow. The results (Fig. 7a-e) show that an increase in the temperature of PV panel led to an increased power of the PV panel which reaches a maximum value at around noontime (Gupta and Tiwari 2016;Kaldellis and Kokala 2010;Katz et al. 2001;Moharram et al. 2013). Figure 7a shows that the maximum solar power inputs of 294.0, 304.3 and 338.3 W reached at the temperatures of 46.8, 44.9 and 44.9°C can be obtained from the panel of PV cooled by the water flow rates of 12, 18 and 24 L h -1 , respectively. ...
Article
The photovoltaic panel cooled by a water flowing is commonly used in the study of solar cell to generate the electrical and thermal power outputs of the photovoltaic module. A practical method is therefore required for predicting the distributions of temperature and photovoltaic panel powers over time. In this study, the second-degree polynomial models were established to predict the distributions of temperature and various photovoltaic panel powers, while the linear models were used to analyse the correlation between solar power input and various photovoltaic panel powers. The results showed that the maximum values of electrical power, thermal power and power loss reached at the temperature around noontime. The same value of a photovoltaic panel power recorded at two temperatures was verified from the experiment of photovoltaic panel cooled with different cooling water flow rates. A volumetric flow rate of cooling water passing through the copper tubes determines the amount and characteristics of additional electrical power generated by the water-cooled photovoltaic panel, while a power loss in the photovoltaic panel is very sensitive to the rate of water flow. This study provides a new insight into the management of solar energy for the residential and commercial purposes in the future.
... However, a separate study focused on Doha, found that weekly cleaning of the PV surface can improve power output by up to 6% [113]. Another study that looked at the effect of dust deposition on PV in Athens, Greece, found that PV performance drops by 6.5% within 8 weeks [114]. This is mainly due to the reduction in light transmittance. ...
Article
Full-text available
In this manuscript we review research on the feedback mechanisms between photovoltaic energy production and the urban environment, with an emphasis on synthesizing what is known, while drawing attention to limitations, and indeed errors in, the literature on this topic. We include in our analysis studies on photovoltaic (PV) systems in urban settings – on buildings, as shade structures, or as stand-alone arrays within an urban environment. We further limit the review to studies that investigate how the urban setting affects the performance of PV systems or how PV systems affect their surrounding urban environment. Our review is based on a systematic search of the literature, which revealed 116 unique articles that addressed the underlying questions in a meaningful way. While there are conflicting results reported across this body of literature, our review and synthesis reveal two key findings: (1) PV can significantly warm the city during the day, provide some cooling at night, and potentially increase energy use for air conditioning of buildings in some climates and building types; and (2) placing PV in an urban setting can adversely affect PV efficiency, reducing overall power production up to 20% in comparison to PV applications in rural settings. It is recommended that future developments of PV technologies focus both on increased efficiency and the need to increase reflection of wavelengths of energy not converted to electricity by the PV cells. Furthermore, designs for urban PV systems should explicitly consider the effects of elevated urban temperatures, pollution, and shading on system performance.
... Hassan et al. [7] pointed out that the PV panels' power output reduced 33.5% for exposure of one month and 65.8% for exposure of six months. Soil and dirt can cause up to a 15% reduction in PV efficiency [8]. In areas with desert climates, dust accumulation is very high, affecting the PV module efficiency. ...
Article
This study aims to analyze many efficiency-enhancing and improvement activities such as manual and natural cleaning, a PV power plant type rainwater harvesting system, thermal monitoring, and snow load removal in a 600 kW grid-connected photovoltaic (PV) power plant. The study shows that up to 5.66% power reduction can occur for PV modules that have been dirty for close to one year. It was determined that the dust removal effect of the rain was up to 0.94%. This study showed that the potential for collecting rainwater from a small part of the PV plant is approximately 118 m³/year and that the harvesting system will reach 1646 m³/year when applied to the whole plant. A snow load of 0.117 kN per m² was removed. On the basis of three days, 50–75% higher energy production was achieved compared to the other power plant with snow load. Snow removal on PV arrays both prevented PV degradation and resulted in increased power generation, while panel cleaning improved energy efficiency. This study an innovative approach with rainwater harvesting from solar power plants with large surface area for the use in panel cleaning and agriculture of the obtained water, which is a novel idea in increasing the efficiency of the power plants, combating climate change and drought.
... For this delimma, the meteorological data will effectively help the data analysis on the power generation [94][95][96]. The GIS data analysis including roof angle, shading impact, roof area, house type, ground inclination, occlusion classification [54], guano, snow, and smog [97]. Recent research progress in these directions is crucial for future SBIPV systems [98].When extreme weather happening, residents can clean up the PV panels earlier to reduce grid dependence baseds on the weather data. ...
Article
The smart building-integrated photovoltaic (SBIPV) systems have become the important source of electricity in recent years. However, many sociological and engineering challenges caused by temporal and spatial changes on demand-side and supply-side remain. In this paper, the barriers and traditional data utilization of SBIPV system causing the above challenges are summarized. Data-driven SBIPV was firstly proposed, including four aspects: Data Sensing, Data Analysis, Data-driven Prediction, and Data-driven Optimization. Data sensing goes beyond the technical limitations of a single measurement and can build the bridge between demand- and supply-side. Then, the demand-side response and electricity changes in supply-side under various environmental changes will also become clear by Data Analysis. Data-driven Prediction of load and electricity supply for the SBIPV is the basis of energy management. Data-driven Optimization is the combination of demand-side trading and disturbed system optimization in the field of engineering and sociology. Furthermore, the perspective of data-driven SBIPV, technologies and models, including all four data-driven features to make automated operational decisions on demand- and supply-side are also explored. The data -driven SBIPV system requiring much greater policy ambition and more effort from both supply and demand side, especially in the areas of data integration and the mitigation of SBIPV system.
... Sites produced with grains of sand can also contain particulate matter of dust. The performance of PV panels [10] was also studied; dust has an effect in solar panel performance. The decrease in the maximum power produced depends on the particle density and size [11][12][13][14][15][16]. ...
... Consequently, due to the presence of the layer of dust particles on the solar photovoltaic module surface, the solar radiation will be reflected or absorbed resulting in the decrement of the transmissivity which further leads to degradation in the efficiency of the photovoltaic module. Table 2 illustrates the consequences of dust particles on the solar photovoltaic module carried out in different countries for different tenure, summarized by different published works [35,37,[67][68][69][70][71][72][73][74]. ...
Chapter
Full-text available
The demand for electrical energy is increasing rapidly due to the rapid growth of the population. Meeting such demand for energy in a renewable, sustainable and eco-friendly way led to the adoption of the solar photovoltaic (PV) module. In that context, it is necessary to extract the maximum amount of electrical energy from the solar SPV module. Various factors influence the performance of the PV module. One such factor is the deposition of dust particles on the module surface, which has a detrimental effect on the output characteristics by lowering the efficiency. In this work, a survey of the deposition of dust particles cooperates various mechanisms of deposition, factors affecting the deposition, its impact on the efficiency of solar photovoltaic module and various methods to minimize this effect has been covered. It was clear that the dust accumulation is a serious issue which cannot be ignored, as it hinders achieving the renewable energy target and also delayed the return of investment. There is a requirement for a comprehensive study on the effect of dust in different geographical regions and acquire the data so that new techniques and methods can be evolved to mitigate the effect of soiling on the surface of the solar PV modules at that specific location.
... Moreover, it is confirmed that the daily energy loss can reach more than 20% in areas that lack rain for long periods. Additionally, authors in [20] have concluded that the reduction in the amount of PV generated power is a function of the site where the system is deployed. ...
Article
Full-text available
Recent technological encroachments have evolved the usage of Internet of Things (IoT) and it is becoming an elementary part of our life. Regarding the photovoltaic (PV) renewable energy-based systems there is a lot of potential to integrate the IoT based solutions in order to enhance the generation capabilities and to diminish the energy losses in the electricity production. Energy losses can occur due to several causes in the case of PVs. This work deals with the photovoltaic energy losses caused by the dust deposition. The idea is to intelligently employ the IoT framework in this regard. The system is based on a modular design approach. Each module digitizes the status of a concerned PV panel by using an embedded front-end controller. The readings are conveyed to a specifically developed automatic maintenance decision algorithm. The intended PV module data is logged to cloud in a real-time fashion for post analysis. In parallel, the designed software analyzes the instantaneous open-voltage value of the PV panel and make real time decisions if a maintenance notification is required or not. In this fashion, they can efficiently act for the PV maintenance in order to get the most out of the PVs over the system lifecycle. The constructed prototype successfully achieved its goals of automatically detecting unexpected voltage drops from a PV panel due to dust disposition and reported it to the concerned parties.
... Besides, several authors have investigated the soiling losses in the Mediterranean region (for ~30 • -tilted rooftop PV systems in coastal cities with a Csa climate, i.e. a warm temperate climate with a hot dry summer). They reported record soiling-related power losses during the dry season, reaching 6.5% in Athens (Greece) after 8 weeks (Kaldellis and Kokala, 2010); 8-15% in Limassol (Cyprus) after 12 weeks (Kalogirou et al., 2013), and 15% in Málaga (Spain) after two months (Piliougine et al., 2008). Besides, the annual energy yield is strongly affected by soiling in cities exposed to high pollution levels or harsh climatic conditions. ...
Article
Dirt accumulation (“soiling”) on the surface of photovoltaic (PV) modules may cause significant energy output reductions (“soiling losses”). The adoption of suitable soiling mitigation strategies can make PV deployment more attractive, but it requires the assessment of the magnitude and the seasonal evolution of the soiling losses at local scale, as they are highly dependent on the regional climate, the meteorological conditions and the surrounding environment. For the purpose of estimating them for building integrated and building applied PV systems in Madrid city, Spain (i.e. under Mediterranean climate conditions), a systematic optical analysis was performed during a 15-month experimental campaign using a rooftop soiling test bench which allowed the exposure of multiple glass coupons at two tilt angles of interest (8° and 35°) in a semiurban environment. There was no cleaning schedule so that the exposed glass coupons were simply washed away by the rain. Broadband transmittance reductions (Tloss) indicated the occurrence of low soiling losses with yearly-averaged Tloss values of 1.49% at 8° and 1.04% at 35°. Regarding the soiling evolution, the local precipitation regime played a fundamental role. Soiling losses were negligible during frequent-rainfall periods, experienced a moderate increment in spring (March–April), and increased notably during the dry summer season, reaching annual maxima in July (5.13% at 8° and 3.89% at 35°). In order to minimize the local soiling losses, performing module cleaning operations at least during these two times of the year is encouraged. Concerning the soiling spectral effects, the optical loss increased towards shorter wavelengths, making wide-bandgap PV technologies more sensitive to local soiling. Finally, when applying PV performance prediction models which include soiling, the recommended local values for the daily soiling rate and the rain threshold are 0.11%/day and 5.3 mm at a tilt angle of 8° and 0.09%/day and 3.3 mm at a tilt angle of 35°.
... They observed that a minimum value of power was 3.88W when the PV module was accumulated by particles of rice husk. A similar type of research has been conducted by Kaldellis and Kokala [15] which concluded that the effect of dust on PV module performance varies from site to site. In this regard, Appels et al. [16] conducted research and proved that the problem of dust settlement in Belgium is not severe as compared to Middle East. ...
Article
Full-text available
Photovoltaic (PV) modules are widely used for harnessing solar energy which ensure maximum output when their glass surface is clean. However, PV modules are open to dust, grime and other contaminations which get deposited on their surface causing reduction in transmittance and hence their efficiency reduces. It is therefore required to clean the glass surface of PV modules time to time either manually by labor or using some special arrangements such as automated systems. However, these techniques are either laborious or require extra energy. Therefore, another solution to offset such complications is to use chemical coatings which ensure self-cleaning of glass surface by increasing water contact angle. In the present study, two types of water repellent chemicals (such as trimethylchlorosilane and hexamethyldisilazane) have been used to coat the glass surface using dip coating technique. The performance of such coated glass slides has been investigated using some important characterization techniques, such as finding transmittance by spectrophotometer and measuring water contact angle using a high resolution camera. Moreover, the self-cleaning effect has been observed using a microbalance to measure dust on coated glass exposed to open atmosphere and compared with uncoated glass. The results revealed that these coatings have increased the water contact angle up to 149% which reduces friction between the glass surface and water droplets. Moreover, the friction reduction helps in mobility of water droplets which in turn can easily carry out dust along with them, thus improving the efficiency of PV module.
... [1,2]. Up to 50% of energy loss can occur as a result of the pollution on solar panels [3][4][5]. Even in the desert, cleaning the solar panels once the wet season is done is necessary for stable electricity generation [6]. ...
Article
Full-text available
An adaptive driver motor was developed to use in PV panel cleaning systems in this study. The amount of energy produced from PV panels is directly related to parameters such as the rate and angle of solar irradiance falling on the panel. Covering the surface of PV panels with dust, dirt, etc., significantly reduces the amount of energy. A lot of research/development is being done with panel cleaning. In this study, a Linear Brushless Direct Current (BLDC) motor was designed as an alternative drive element to be used in the methods used for cleaning the panels. In this study, analytical design and electromagnetic and structural analyses of linear BLDC were performed. The motor prototype was produced, and appropriate driver was selected and then mounted on the motor test setup. The test results on the system have shown that the designed motor and the system can be used for panel cleaning. Depending on this, cleaning technic produced energy was increased by 22%. Most of the external systems used either create an additional load on the panels or need an additional motor or reducer for linear motion. The unique aspect of the work is that it can provide linear motion for the cleaning equipment without additional load on the panels. In addition, due to the large thrust produced by the motor, it will be possible to clean the panels placed on the same axis with a single motor in successive panel series.
... Reduction of energy by 7% per year along with cleaning and rainfall One year Iran [91] Reduction of energy by 44% per year without cleaning and rainfall Nonlinear relationship between solar PV cell performance loss and dust deposition six months Qatar [76] About 40% reduction in efficiency six months Saudi Arabia [92] Performance drop of more than 50% at the end of the experiment six months Saudi Arabia [65] The power loss of 8-12% per month Four and a half months Iran [53] Performance drop of 10% at the end of the experiment One hundred days Qatar [67] The power loss of 10% three months Iran [93] The Power loss is up to 8.8%, and efficiency up to 11.86% three months Jordan [58] Reduction of transfer coefficient by 25% Seventy days Iran [70] The power loss of 21.47% Seventy days Iran [36] Average monthly performance drop of 1% in less desert areas and up to 11.5% in farmland in Central California two months America [94] More than 4% drop in panel performance after 15 days and 15% drop in performance at the end of the test two months Spain [95] The power loss of 6.5% at the end of the experiment Eight weeks Greece [96] The average performance drop was 13% during the test period Six weeks Saudi Arabia [97] The average performance drop was 6% during the experimental period Five weeks Saudi Arabia [98] Performance drop of 10% at the end of the experiment Five weeks Emirates [68] Average daily power loss 4.45% One Month Iran [99] In no cooling condition, 46% power reduction One Month Iran [26] In cooling condition, 29% power reduction At a slope angle of 0°, the average daily energy decrease is 58.2% ...
Conference Paper
Full-text available
Due to the upsurge in energy demand as well as the numerous problems associated with the use of nonrenewable energies, such as environmental concerns, alternative energies are needed. Solar energy is among the most attractive options, but as with any renewable energy, its reliance on the environment creates uncertainty. This paper presents a comprehensive analysis of the recent and related studies investigating the influential factors on solar photovoltaic panel performance. The literature review reveals that environmental factors, especially dust, predominantly influence solar photovoltaic panel operation. Evaluation of the interaction between each of these factors, solar photovoltaic panel factors, and dust is performed in this study. These findings will be useful to those involved in the study, experiment, design and development of solar photovoltaic systems, particularly in dusty areas.
... Their economic evaluation recommended cleaning once in a year for the system in Perth and twice a year for the system in Indonesia. Kaldellis and Kokala [13] also quantified the energy loss due to soiling in Greece on a 10 kW p solar PV system and reported annual income losses amounting to 400 €. ...
Article
Full-text available
The effect of installation azimuth angle in the optimization of the cleaning cycle of a solar photovoltaic plant was experimentally investigated in this study. The optimum cleaning cycle was determined using Particle Swarm Optimization algorithm cognizance of the fact that different orientations have different soiling rates. Soiling rates on three different azimuth configurations were experimentally investigated and an exponential soiling loss model was developed for each configuration for use in the optimization problem. Azimuth angle differences of ±12.5% were found to have a significant influence on soiling of as much as 28.29% for the selected location. The North of North West configuration was found to be optimal as opposed to the generally accepted North configuration for maximum energy generation at a minimum cost of energy. This configuration generated 0.87% more energy at unit energy cost of $0.093 compared to the North configuration which had a minimum cost of $0.113. The optimized cleaning cycles were 35 days for the optimal configuration while the North configuration had an optimized cleaning cycle of 28 days. A 17.7% difference in the cost of energy was recorded due the influence of soiling. The study revealed that for minimizing the unit energy cost, it is necessary to take into effect the influence of soiling.
... It is also concluded that the solar tracker improves power output and helps to reduce the dust accumulation effect by 50% at an off-peak time. In [22], Kaldellis introduced an experimental study to determine the reduction in efficiency of photovoltaics due to deposition of natural air pollution on the PV panels, where they concluded that the efficiency has been decreased by 0.4% per month when it is exposed to outdoor without cleaning. In [30], Dincer studied many factors' effects on solar cell efficiencies such as changing cell temperature, using maximum power point tracking (MPPT) with solar cells, and energy conservation efficiency for solar cells. ...
Preprint
Full-text available
Electricity generation from the sun, the most important renewable energy source, has significant environmental, health, and economic benefits. As a result, many countries intend to invest heavily in improving this technology and constructing more solar power plants. Environmental conditions (such as temperature, humidity, solar radiation, and dust concentration) can, however, cause issues when establishing these stations, resulting in a significant reduction in the amount of energy that can be generated. The current investigation is centered on the behavior of photovoltaic modules under real-world operating conditions. Over the course of a year, various photovoltaic module technologies such as monocrystalline, polycrystalline, and thin-film were tested under identical operating conditions: autonomous systems with comparable energy conversion capabilities, the same electric load, and similar data acquisition systems.in the Egyptian Region, under the same weather conditions The conversion efficiency for each module in each environment was calculated using temperature, humidity, solar irradiance, power, and the I-V operation point. parameters. The operating parameters and environmental conditions of monocrystalline, polycrystalline, and thin-film technology are compared in this paper.
... It is also concluded that the solar tracker improves power output and helps to reduce the dust accumulation effect by 50% at an off-peak time. In [22], Kaldellis introduced an experimental study to determine the reduction in efficiency of photovoltaics due to deposition of natural air pollution on the PV panels, where they concluded that the efficiency has been decreased by 0.4% per month when it is exposed to outdoor without cleaning. In [30], Dincer studied many factors' effects on solar cell efficiencies such as changing cell temperature, using maximum power point tracking (MPPT) with solar cells, and energy conservation efficiency for solar cells. ...
Article
Full-text available
Electricity generation from the sun, the most important renewable energy source, has significant environmental, health, and economic benefits. As a result, many countries intend to invest heavily in improving this technology and constructing more solar power plants. Environmental conditions (such as temperature, humidity, solar radiation, and dust concentration) can, however, cause issues when establishing these stations, resulting in a significant reduction in the amount of energy that can be generated. The current investigation is centered on the behavior of photovoltaic modules under real-world operating conditions. Over the course of a year, various photovoltaic module technologies such as monocrystalline, polycrystalline, and thin-film were tested under identical operating conditions: autonomous systems with comparable energy conversion capabilities, the same electric load, and similar data acquisition systems.in the Egyptian Region, under the same weather conditions The conversion efficiency for each module in each environment was calculated using temperature, humidity, solar irradiance, power, and the I-V operation point. parameters. The operating parameters and environmental conditions of monocrystalline, polycrystalline, and thin-film technology are compared in this paper.
... There is an effective decrease in life-span cell and output efficiency of PV solar panel due to long time dust accumulation 10 .The airborne dust particles and accumulation of dust on the surface of PV cell influences the working of PV solar cell because solar radiation which is the major factor for generation of power gets blocked or scattered by the dust particles. This produces power generation irregularities and degrades reliability of solar PV cell [11][12][13][14] .Muhamed et al. investigated on the effect of dust deposition on the performance of PV cell in eastern part of Saudi Arabia.The study revealed that the output power of PV module reduced by 20% in single dust storm and upto 50% output power decreases if the cleaning period exceeds six months. However, rainfall reduced the dust accumulation increasing the PV cell efficiency and 50% effect of dust on power output was reduced by tracker. ...
Conference Paper
Solar energy usage is facing many issues; one of those is the accumulation of the dust on the surface of the solar panel which would highly lower its efficiency. Comparison between the dusty photovoltaic panel and clean photovoltaic panel showed that the dust on photovoltaic panel scan reduce the power and efficiency significantly, where the highest power generation decrease was 5.23%and the highest power generation efficiency decrease was 5.55%. The tilt angle of the PV installation plays a major role in the amount of dust accumulated on the devices, where higher tilt angles result in decreased dust concentrations. Different tilt angles can produce varying non-uniform dust patterns on the device surface. The results showed a constant power loss between 3% and 4% for the optimal tilt angle.The present work studies the effect of dust accumulation on installing fixed solar panels with different inclined angles 15 0 , 33 0 , 45 0 , 60 0. The solar panels efficiency and lose power rate values for the inclination angles 33 0 and 45 0 were ranged between the values of 15 0 and 60 0 inclinationangles.Dust accumulation was found a function of the tilt angle and it increases by 37.63%, 14.11% and 10.95% with respect to the clean module for the 0 0 , 25 0 and 45 0 tilted panels, respectively. A novel, simple, cheap, and robust system has also been proposed to mitigate the effect of dust usingforcedairdraftproducedbyafan.
... The Effect of Soiling on Large Grid-connected Photovoltaic Systems in California and the Southwest Region of the United States Kaldellis (Athens, Greece) [166] 2010 Quantifying the Decrease of the Photovoltaic Panels' Energy Yield due to Phenomena of Natural Air Pollution Disposal Mani (Review) [167] 2010 Impact of Dust on Solar Photovoltaic (PV) Performance: Research Status, Challenges and Recommendations Kaldellis (Simulation) [168] 2011 ...
Article
Full-text available
This review provides a comprehensive, detailed description and contextualization of soiling research evolution in the solar energy field throughout time. The analysis consists of past soiling research, including important notes on notable works and main researches. The current state of the art is presented, followed by an extended literature survey covering from 1942 to 2019, facilitating the finding of primordial research concerning each of the available technologies, and enriching knowledge regarding the existing extensive research database. Moreover, soiling analysis and comments are made for several specific topics, such as cleaning techniques and environmental effects on soiling deposition. Finally, future prospects and research directions on the soiling effect are given.
... The reduction in power generated by a PV system due to the soiling is a function of the exposure time (Mohandes et al. 2010;Kaldellis and Kokala 2010;Said et al. 2015;Mohamed and Hasan 2012). However, the exposure time does not provide sufficient information on soiling losses. ...
Article
Full-text available
This work is a first part of the study in development on the mapping of soiling losses in the region of Rabat-Sale-Kenitra in Morocco. To perform the work, two holders of glass samples have been constructed and installed in two different sites of Sale City for three successive periods (from April to June 2019). At the end of each period, the transmittance losses of the glass samples as well as the mass of deposited soils are systematically measured. SEM (scanning electronic microscopy) analyses are also performed for more investigation and deep understanding. The obtained results show that the relationship between soil mass density and glass transmittance loss is not always linear as could be expected. They also show that soiling losses are strongly depending on the environment and nature of the surrounding installation spaces. The SEM analysis results of the 1st period and the inclined surfaces have shown that particles are greater in the range of 2–11 μm and the majority tends to have a regular shape in the two sites. Nevertheless, the frequencies are different. From this study, it can be concluded that it is highly recommended characterizing the site where soiling measurements are conducted not only by its location/city but also by its environment characteristics.
... The researchers were interested in proposing several models, and techniques for determining the variables of PV systems. Some studies in literature modeled the transmittance ratio (Elminir et al. 2006), decrease in effective solar energy gain (Niknia, Yaghoubi, and Hessami 2012), degradation rate (Biryukov 1998), solar cells power, and efficiency (Cabanillas and Munguía 2011), or I-V characteristics (Kaldellis and Kokala 2010). However, there are many limitations and constraints of the proposed models, and some of them are suitable for some cases and locations. ...
Article
Solar cells convert the irradiance to electricity, but environmental conditions affect cell performance. In this study, a general model for dust accumulation effect on solar cell performance is proposed. An improvement is introduced to the solar cell one-diode model by considering dust impact to simulate solar cell performance and particularly I-V characteristics. In this study, the novelty is to propose a dust model and improve the single-diode model. The proposed model accounts for the impact of dust on the PV performance by taking into consideration the dust ingredients. Three major components of Oman dust (SiO2, CaO, and Fe2O3) in different proportions were adopted to verify the proposed model using a 4.18 W solar cell. Also, dust samples were collected from six locations in Oman and used for validation in the lab by using a 125-W conventional PV module and solar simulator. I-V characteristics and power losses were determined to compare experimental, ideal, and proposed model results. When mixing 10 g of SiO2, CaO, and Fe2O3 to form 30 g of dust on the cell, the short-circuit current is 42.86% higher in the ideal model than the measureds short-circuit current, while the short-circuit current of the proposed model was 2.79% lower than the measured values. The results obtained from the proposed model are consistently close to the results from the experimental measurements even when using different masses of dust ingredients.
Article
Utilizing solar energy to generate electricity on large scale photovoltaic (PV) power plants became a trend as a new option adopted by many countries. The optimum installation of PV power plants depends on the geographical location, which specifies irradiation, latitude, longitude, tilt angle, orientation, etc. However, the PV panel affected by many environmental parameters, which has a significant impact on the power productivity, conversion efficiency, and cost of energy. Dust is one of the essential parameters that affect PV panel performance, yield, and profitability. However, the dust characteristics (type, size, shape, meteorology, etc.) is geographical site specified. Many researchers investigated PV panel dust cleaning and mitigation methods. This paper put into perspective the recent investigations of dust impact on PV systems and decent cleaning methods. It is found that daily PV power losses and monthly efficiency reduction due to dust in some locations is more than 1% and 80%, respectively, which is relatively high. The present paper aims to provide an appraisal of dust problem and cleaning methods status, challenges, and prospects. Also, a critical review is developed for researchers interested in this field. It is found the main dust elements which have impact are six dust pollutants. Also, the study conclude that selection of the dust cleaning method depends on many parameters in term of technical and economic aspects. Finally, this paper contains a comprehensive review of dust problem and cleaning methods for engineers, designers, and researchers dealing with PV systems.
Article
The exponential growth of global capacity along with a reduction in manufacturing costs in the last two decades has caused photovoltaic (PV) energy technology to reach a high maturity level. As a consequence, currently, researchers from all over the world are making great efforts to analyse how different types of degradation impact this technology. This study provides a detailed review of the impact of different optical degradation mechanisms, which mainly affect the transmittance of the top-sheet encapsulant, on the spectral response of the PV modules. The impact on the spectral performance of PV modules is evaluated by considering the variations of the short-circuit current since this is the most widely used parameter to study the spectral impact in outdoors. Some of the most common types of optical degradation affecting the performance of PV modules worldwide, such as discoloration, delamination, aging and soiling have been addressed. Due to the widely documented impact of soiling on the spectral response of modules, this mechanism has been specially highlighted in this study. On the other hand, most of the publications analysed in this review report optical degradation in PV modules with polymeric encapsulant materials. Furthermore, an innovative procedure to quantify the spectral impact of degradation on PV devices is presented. This has been used to analyse the impact of two particular cases of degradation due to soiling and discoloration on the spectral response of different PV technologies.
Article
Full-text available
The power generation everywhere in the world is mostly generated from nonrenewable technology source particularly fossil fuel. So, these resources will be reduced to utilizing in future. Among these power generation technologies, Photovoltaic (PV) system have got great position by several reasons. This paper gives general review of PV module performance and effect of dust deposition. The deposition of dust has significant effect in transmittance of solar irradiation in the PV module. The dust deposition effect of multiple areas is discussed in literature review.
Article
The performance of the solar photovoltaic (PV) panel is greatly affected by a rise in operating 8 temperature. A combination of phase change material (PCM) and natural water cooling 9 system for effective thermal management of the PV panel is examined to tackle this issue. 10 Experimentation involved incorporating OM 35 PCM at the tedlar surface of the PV panel 11 and water was allowed to flow from the bottom portion of the PCM chamber. Four different 12 cases considering the direction (bottom to top and top to bottom) and period (continuous and 13 maximum allowable temperature mechanism) of cooling water flow were evaluated and 14 compared with the reference panel. Various parameters such as electrical/ thermal efficiency, 15 energy balance and exergy analysis of the PV panel with and without cooling are compared 16 and discussed. Experimentation indicated that the performance of the PV panel augmented 17 due to the incorporation of PCM with natural water circulation. Further, it was identified that 18 the top to bottom continuous water supply cooling technique showed better performance than 19 other cases with an increase in average electricity generation, electrical efficiency, power 20 enhancement percentage, average temperature reduction, maximum overall exergy output and 21 exergy efficiency of 11.92%, 12.4%, 13.54%, 5.4°C, 26.07% and 8.08% respectively.
Article
Compared with the cleaned photovoltaic (PV) modules, the output power of the dusty PV modules decreases. In this paper, the factors influencing dust concentration on the PV module glazing surface are studied and discussed. Based on the optical analysis, a method of calculating the output power reduction of PV modules due to dust deposition on its surface is proposed. According to changes of daily PM10 and rainfall, the output power reduction of PV modules can be calculated, which lays a foundation for the formulation of the cleaning strategy. In addition, experiments of dust deposition on the surface of PV modules are designed in Changzhou and Yantai, China, to verify the theoretical output power calculation model. According to the result of experiment and calculation, not only can this method accurately calculate the daily power loss caused by the dust deposition on PV modules surface, but also it can make up for the large fluctuation of outdoor experiments (measurement of the output power reduction of PV modules due to dust deposition) under the changeable weather of radiation.
Article
The application of renewable technologies and in particular solar photovoltaic (PV) market has grown rapidly throughout the past 15 years worldwide. Despite the market growth, one of the main factors limiting the application of PV panels is the degradation issue or power decline over time, highlighting the need of further studies on degradation rate and reliability assessment to predict panel life expectancy, economic values and financial risks. PV panels behave differently under certain conditions, and energy production of panels varies not only with the capacity of the system but also with the type of modules in panel. Researchers have also studied how different modules/panels perform for long periods of time, when exposed out in the field. In this article, a literature review of PV panel performance over time was accumulated from different resources to identify the sources of uncertainty about their performance, reliability, and durability under internal and external factors. The results show that both the internal factors such as cell interconnect breakages alongside external ones such as the sunlight, temperature change or dirt accumulation were determined to be the primary causes for the power loss and reduced energy generation in the PV panels and highlights further research in this area.
Article
Carbon neutrality has become a global consensus for green development, and solar photovoltaic power generation has increasingly become one of the key technologies for carbon reduction. Large-scale photovoltaic power plants are often built in arid and sandy areas, which carry a large number of dust particles in the air. Dust deposition on photovoltaic modules has a significant impact on the transmittance, temperature, and roughness of photovoltaic modules, reducing their power generation efficiency and service life. The paper has the following structure: i) relevant research all over the world; ii) the mechanism of dust deposition and the influencing factors on photovoltaic modules; and, iii) some current methods of cleaning are summarized, and the mechanism of self-cleaning coatings for dust deposition prevention. It found that the process of dust deposition is accomplished dynamically and repeatedly under the joint action of several forces. And the diameter of the particle, the installation angle of photovoltaic modules and wind speed have a great influence on the behavior of dust deposition. Self-cleaning coatings have an obvious effect on the prevention of dust deposition. The paper also looks forward to future research methods of particle deposition and cleaning on photovoltaic modules.
Preprint
Full-text available
A grid-connected photovoltaic system was tested and investigated for the entire year under desertic weather exhibited. The system contains 1.4 kW PV and 1.7 kW inverter-the data was measured every second and used to model and evaluate the system performance. However, dust is one of the essential parameters that affect grid-connected photovoltaic performance, yield, and profitability. In this paper, a proposed model has been takes into consideration the dust impact on grid-connected photovoltaic performance in a novel way. The outcomes demonstrate that the proposed model precisely anticipated the system performance and validated through experimental results. However, it is found that the photovoltaic, inverter, and performance efficiencies are 10.80%, 94.00%, and 73.00%, respectively. Besides, the average yield factor is 141.39 kWh/kWp, and capacity factor is 19.64%. It concluded that the system productivity in Oman is within the prospected rate. The information in this paper is valuable for investors, researchers, and engineers interested in grid-connected photovoltaic and dust impact in Oman and neighboring countries.. "A novel model and experimental validation of dust impact on grid-connected photovoltaic system performance in Northern Oman." Solar Energy 206 (2020): 564-578. Link: https://www.sciencedirect.com/science/article/abs/pii/S0038092X20306575 2 List of Symbols () : Angular losses [%]. assumed as a constant at 9.81 m/s 2 ] i : Interest rate [basis points] I: Current, [ A ] I L : PV current, [A] I D : Diode current, [A] I o : is the saturation current of the diode, [A] I sc : PV short circuit current, [ A ] I mp : PV maximum power current, [ A ] J(d p) : Flux particles [particles/cm 2 ]. k : is a constant of value 1.38×10-23 , [J/K] n : is the diode ideality factor, [-] P max : PV maximum power, [W] P in : Input power, [W] P out : Output power, [W] P pump : Hydraulic head for requisite pump [J/s or W] q : is the elementary charge 1.6×10-19 Coulombs, [C] q(d p) : Mirror reflectivity reduction Q : Effective absorbed solar energy gain [in kW]. R SH : Parallel shunt resistance, [Ω] R S : Series resistance, [Ω] r : Degradation rate [-]. S(d p) : Glass transmissivity. T : is the cell temperature, [Kelvin] V: Voltage, [V] V oc : PV open circuit voltage, [V] V mp : PV maximum power voltage, [V] η: Efficiency, [-] 3 ρ : Fluid density [kg/m 3 ] ΔQ : Decrease in effective solar energy gain [in kW]. δ : Amount of dust on mirrors [mg/m 2 ]. ψ(d p) : Efficiency of surface cleaning [-]. δM : Specific mass of the pollutant. ρ s : Particle density [mg/cm 3 ]. : Transmittance ratio [-]. Ω () : mass accumulation [-]. w : Moisture content [%].
Article
We report on the impact of natural soiling on PV module performance loss in terms of dust potency (i.e., soiling loss per unit area dust mass) affected by dust composition and environmental conditions. Samples of accumulated dust mass (ADM) on PV panels from Doha, Qatar, were collected at different periods over two years. Our analysis demonstrated that dust accumulation rate and dust potency exhibited seasonal patterns influenced by environmental conditions. The measured dust potency varied significantly from month to month, ranging from 2 to 3.7% g−1 m2 that situates in the range of 2-8% g−1 m2 found in the literature. The lower dust potency was observed during the summer months, characterized by strong winds and low humidity. Soiling loss may be seen as a function of ADM and the dust potency, with the latter being a function of dust physico-chemical properties. ADM also has a significant seasonal fluctuation both in terms of particle size distribution and chemical composition. The dust potency is found to be impacted by the particle size, elemental carbon (EC), organic carbon (OC), and ions contents of the dust. ADM with lower dust potency has shown larger size particles and low EC/OC contents, while the effect of soluble ions on dust potency is found to be complex, due most probably to the interactions with humidity. Finally, based on the experimental and literature data, we developed a practical and straightforward model to estimate PV soiling loss as a function of dust mass and dust potency.
Article
Solar photovoltaic (PV) is a promising and highly cost-competitive technology for sustainable power supply, enjoying a continuous global installation growth supported by the encouraging policies and commercial markets. However, air pollution and soiling of PV modules prevail worldwide, potentially casting a shadow on solar PV power generation. This study presents a comprehensive review of the documented impact of air pollution and PV soiling on solar resources and techno-economic performances of PV systems. Both air pollution attenuation and soiling could significantly reduce the solar PV power generation globally, and soiling losses contribute to most of the total power reduction in most regions except in high-polluted areas. In addition, considering the natural soiling processes, the influencing parameters of soiling such as environmental and configurational factors and their correlation to dust deposition on PV surface are discussed. Furthermore, this study introduces the impact of air pollution elimination on surface solar radiation and solar PV power generation. Given the current novel coronavirus disease 2019 (COVID-19) pandemic, studies related to its effects on the solar PV sector are discussed in the present review. The reported soiling mitigation approaches and technologies are systematically compared. Finally, the current research challenges are stated, and suggestions for future works in improving the penetration of solar PV applications are provided to help promote solar power generation towards carbon neutrality all over the world.
Preprint
Full-text available
Utilizing solar energy to generate electricity on large scale photovoltaic (PV) power plants became a trend as a new option adopted by many countries. The optimum installation of PV power plants depends on the geographical location, which specifies irradiation, latitude, longitude, tilt angle, orientation, etc. However, the PV panel affected by many environmental parameters, which has a significant impact on the power productivity, conversion efficiency, and cost of energy. Dust is one of the essential parameters that affect PV panel performance, yield, and profitability. However, the dust characteristics (type, size, shape, meteorology, etc.) is geographical site specified. Many researchers investigated PV panel dust cleaning and mitigation methods. This paper put into perspective the recent investigations of dust impact on PV systems and decent cleaning methods. It is found that daily PV power losses and monthly efficiency reduction due to dust in some locations is more than 1% and 80%, respectively, which is relatively high. The present paper aims to provide an appraisal of dust problem and cleaning methods status, challenges, and prospects. Also, a critical review is developed for researchers interested in this field. It is found the main dust elements which have impact are six dust pollutants. Also, the study conclude that selection of the dust cleaning method depends on many parameters in term of technical and economic aspects. Finally, this paper contains a comprehensive review of dust problem and cleaning methods for engineers, designers, and researchers dealing with PV systems.
Article
Full-text available
1. 内蒙古工业大学能源与动力工程学院,呼和浩特 010051;2. 内蒙古自治区可再生能源重点实验室,呼和浩特 010051) 摘 要:该文以呼和浩特城区的倾斜玻璃板和光伏组件为积灰载体,测试并分析了积灰颗粒的粒径分布、形貌特征及元 素组成,研究了太阳入射角与太阳总辐照度变化方向对透射衰减率的影响规律,计算了不同积灰量下由积灰引起的日平 均总透射衰减率。研究表明:呼和浩特城区光伏组件积灰颗粒的体积平均径为 23.10 μm,粉砂质量分数约为 72.77%;积 灰量分别为 2.75、4.59、5.86 g/m 2 时,积灰引起的日平均总透射衰减率分别为 1.29%、3.42%、4.71%;太阳总辐照度增 时段,总衰减率随太阳入射角以类线性趋势正相关变化。太阳总辐照度减时段,总衰减率随太阳入射角以微小幅度先减 小再增大, 当太阳入射角增至 60°时, 总衰减率开始线性增大; 总衰减率最小值所对应的太阳总辐照度比峰值小 168 W/m 2 , 对应的太阳入射角比最小值小 25.5°。该研究可指导呼和浩特城区光伏发电系统除尘方式的选取及除尘周期的预设。
Chapter
Photovoltaic modules are subject to harsh outdoor conditions and thus directly affected by atmospheric heat and subsequent temperature rise. The temperature increase on the panel surface impacts its performance and mechanical properties. This chapter examines the impact of heat on the parameters associated with output power, performance and structural properties of a silicon photovoltaic module. Photovoltaic modules are one of the promising solutions to the global energy crisis. They are considered to be non-polluting, renewable and silent form of energy. They make use of abundantly and freely available sunlight for the generation of electric power. The high operating temperature of PV cells will have adverse effects on the generation efficiency and performance. To improve system reliability and performance, efficient PV module cooling methods have to be employed. The most common methods are thermoelectric cooling, forced and natural air cooling, cooling with phase change materials, heat pipe cooling and hydraulic cooling. This chapter discusses different ways of water cooling employed in PV modules.
Chapter
The electrical energy generated by photovoltaic (PV) modules depends on solar radiation, environmental and climatic factors as well as inherited system and component performances. However, the other external factor such as dust also has significant effects on the performance. This chapter discusses the deposition of dust particles on the PV module surfaces and their effects on system performance. The chapter begins by discussing the fundamentals of a PV module and dust particles originality, transportation and the factors that govern their deposition. Results show that the accumulation of dust particles on PV module surfaces is influenced by dust particles properties (size, shape and chemical properties), environmental conditions (wind speed, location and distance to the dust source, dust concentration and weather condition) and PV module characteristics (tilt angle, orientation and properties of surface material). On the other hand, the presence of dust particles on PV module surfaces reduces significantly the transmitted incident light to the solar cells which in turn decreases the value of the short-circuit current (ISC), maximum power output (Pmax), fill factor (FF), conversion efficiency (η) and energy yield. The rate of decrease of each parameter increases as the dust particles deposition density increases. In addition, the reduction in ISC, Pmax, FF, η and energy yield depends on the physical properties of dust particles such as mean diameter, size distribution and chemical composition. The effect of dust on the performance of PV modules can be eliminated by cleaning the dust particles using different methods. These methods are classified as natural, manual and automatic.
Chapter
Due to volatility in oil prices, decision-makers are looking forward to using renewable energy sources to fulfill their country’s energy demands. Among the other renewable energy sources solar photovoltaic (PV) is considered as the most attractive one due to its abundant solar potential. Large-scale PV installations have been increasing in recent years, specifically desert areas are considered suitable sites. Apart from the low-efficiency issue of the PV system, other aspects are also affecting the performance of solar PV, specifically environmental aspects, such as, temperature, humidity, and dust are influencing the day to day performance of solar PV systems. In a solar PV system, soiling is one of the major factors caused by the accumulation of dirt and dust on the surface of the PV module, which directly reduces the output of the system. In this chapter, a review of the currently available different types of PV modules and dust mitigation techniques are presented. It would be helpful for academicians and researchers to select appropriate techniques and technology for dust removal from the PV module surface according to their requirements and environmental conditions.
Chapter
Full-text available
Photovoltaic (PV) technology is considered as a major drive for achieving exigent energy targets. All around the world, huge photovoltaic power plants for the purposes of energy generation at extremely competitive production cost are being constructed in the arid and desert areas. But this advantage of cost effectiveness seems to be disappeared due to the soiling issue of PV modules. The cleaned PV modules are therefore required in the areas where the panels are more likely to become dirty. The major concern related to the cleaning of PV modules is the strategy utilized for cleaning of extremely competitive PV modules. However, manually cleaning the surface of panels, traditionally, is an economically time exhaustive procedure. Moreover, tiny particles are difficult to remove through manual cleaning. Recently, various researches have been endeavoured towards development of water repelling surfaces with novel structures and viable applicability in self-cleaning solar panels. This chapter will discuss the recent developments in organic superhydrophobic coatings for PV modules. It will be comprised of four parts: Section 1 will highlight the basic concepts and principles of superhydrophobic phenomenon. Section 2 will describe the superhydrophobic coating methods. Organic coating materials and their applications for the self-cleaning of PV modules will be discussed in Sect. 3. Finally, the commercialization challenges and future prospects of self-cleaning coatings will be discussed in Sect. 4.
Book
This book discusses how to reduce the impact of dust and heat on photovoltaic systems. It presents the problems caused by both dust accumulation and heat on PV systems, as well as the solutions, in a collected piece of literature. The Effects of Dust and Heat on Photovoltaic Modules: Impacts and Solutions begins by discussing the properties of dust accumulation on PV modules. It then presents several solutions to this, such as hydrophobic coatings and surface texturing. The second half of the book is used to discuss the effects of heat on silicon PV modules, as well as various cooling approaches. These include water cooling and carbon-based materials. Due to the prevalence of PV systems in renewable energy, this book will be of interest to numerous students, researchers and practitioners.
Article
In this research, the efficiency of photovoltaic (PV) panel surfaces due to environmental pollution (dust, dirt and carbon dioxide etc.) results in the loss of output power. The self-cleaning, photocatalytic, anti-reflection and antibacterial coatings developed to reduce this effect were coated on glass surfaces by the sol–gel method, and the effects of the coatings made on the efficiency of PV panels were investigated. The optical and photocatalytic properties of the coatings made were characterised by contact angle measurement and the scanning electron microscopy, respectively. The panels coated with increased light transmittance on the PV panel surface showed self-cleaning properties, an anti-reflection effect and antibacterial surface formation. Of the coatings made on the panel surfaces, photocatalytic and anti-reflection effects were provided with titanium dioxide (TiO 2 ) and silicon dioxide (SiO 2 ) compounds, and an antibacterial surface was obtained with the diboron trioxide (B 2 O 3 ) compound. Four panels covered with titanium dioxide, silicon dioxide, diboron trioxide and TiO 2 + SiO 2 + B 2 O 3 and uncoated panels were compared. The PV panels are in the external environment, and the most efficient coating determination was made with the data received from the PV system assembly to measure the extra energy produced.
Article
Dust deposition and erosion phenomena on solar photovoltaic (PV) panels substantially reduce their power generation efficiency, useful life and safe operation. In the present study, the dust motion and erosion characteristics of clear and dusty PV panels are investigated using a discrete element model. The physical properties of dust particles and PV panels are experimentally compared between the POWERCHINA Hubei Electric Engineering Corporation (HEEC) Limited building and the power building of the Huazhong University of Science and Technology (HUST). In addition, the effects of the physical properties of dust particles on their dynamic behaviours and erosion rates are discussed. The phase composition of the dust particles at the HUST is mostly SiO2, while the dust particles from the HEEC consist of CaO, Fe2O3, Al2O3, CaCO3, SiO2 and Ca(OH)2. Dust deposits with multiple phase compositions exert a greater negative effect on the panel working performance than dust deposits with a single phase composition. Maximum panel erosion may cause irreparable mechanical damage to PV panels even after cleaning. For dust particles and panels from the HEEC, gravitational, liquid bridge, electrostatic and van der Waals forces are the primary deposition forces; the largest adhesion rates are observed for Fe2O3, Ca(OH)2, SiO2 and Ca(OH)2. The greatest and lowest maximum erosion rates are observed for Fe2O3 and SiO2, respectively. Long-term erosion will lead to a significant increase in the maximum erosion value and the erosion areas and even cause the whole panel to undergo wear. These research findings are very important for power generation optimization and the safe and efficient operation of PV panels.
Article
The deposition and adhesion of dust on the surface of photovoltaic (PV) panels cause a reduction in efficiency and pose safety hazards. It is necessary to investigate the factors and mechanisms of dust adhesion to PV panels to provide theoretical guidance in preventing the dust from adhering on the PV panels. This study analysed the chemical components of actual dust samples from five typical scenarios for PV applications, measured the adhesion strength of dust to PV panels with different organic contents under condensation, observed and analysed the morphology of dust adhesion interface, based on a series of experiments. At last, the mechanism by which organics promote dust adhesion was investigated. The results showed that human activities (life, transportation, production, and so on) were one of the main reasons for the difference of dust composition, especially for organic content. It was discovered that a higher organic content or more condensation cycles enhanced the adhesion strength. Condensation leaded to the accumulation of organics at the adhesion interface to form organic films, which increased the contact area at adhesion interface. Moreover, the organic films may form hydrogen bonds with the hydroxylated silica surface of the PV panels, increasing the adhesion strength. Finally, recommendations were provided to inhibit the dust adhesion to the PV panels.
Article
A grid-connected photovoltaic system was tested and investigated for the entire year under desertic weather exhibited. The system contains 1.4 kW PV and 1.7 kW inverter —the data was measured every second and used to model and evaluate the system performance. However, dust is one of the essential parameters that affect grid-connected photovoltaic performance, yield, and profitability. In this paper, a proposed model has been takes into consideration the dust impact on grid-connected photovoltaic performance in a novel way. The outcomes demonstrate that the proposed model precisely anticipated the system performance and validated through experimental results. However, it is found that the photovoltaic, inverter, and performance efficiencies are 10.80%, 94.00%, and 73.00%, respectively. Besides, the average yield factor is 141.39 kWh/kWp, and capacity factor is 19.64%. It concluded that the system productivity in Oman is within the prospected rate. The information in this paper is valuable for investors, researchers, and engineers interested in grid-connected photovoltaic and dust impact in Oman and neighboring countries.
Article
Full-text available
The aim of this study was to investigate the influence of weather conditions on the number of admissions for childhood asthma in Athens, Greece. Daily counts of childhood asthma admissions (2764) of the three main Children’s Hospitals in Athens, from hospital registries during a 3-year period (2001-2003), were obtained. The meteorological data reviewed consists of daily values of 20 parameters recorded at the National Observatory of Athens during the study period: maximum temperature (Tmax); minimum temperature (Tmin); mean temperature (Tmean); diurnal temperature range (Trange = Tmax – Tmin); day-today change in maximum temperature (ΔTmax); day-to-day change in minimum temperature (ΔTmin); day-to-day change in mean temperature (ΔTmean); day-to-day change in diurnal temperature range (ΔTrange); mean relative humidity (RH); day-to-day change in mean relative humidity (ΔRH); mean water vapor pressure (e); day-to-day change in mean water vapor pressure (Δe); mean atmospheric pressure at sea level (P); day-to-day change in mean atmospheric pressure (ΔP); mean irradiance (I); day-to-day change in mean irradiance (ΔI); mean sunshine (S); day-to-day change in mean sunshine (ΔS); mean wind speed (v) and day-to-day change in mean wind speed (Δv). The performed statistical methods were: (i) Pearson’s χ2 test, using contingency tables and (ii) Factor and Cluster analysis. The application of this 2-part analysis revealed the relationship between the extracted weather types and the frequency of childhood asthma admissions in Athens. The results showed that weather conditions with low temperature, low water vapor pressure and cold anticyclonic presence were significantly correlated with an increase in the number of asthma admissions among children in Athens. The impact of these specific weather conditions on asthma exacerbation should be interpreted either by the asthmogenic effect of humid weather per se or the association with respiratory viral infection, mold’s and mites’ allergy.
Article
Full-text available
The accumulation of dust particles on the surface of photovoltaic (PV) panel greatly affects its performance especially in the dusty areas. In the present work, an experimental and theoretical study has been carried out to investigate the effect of sand dust concentration on the efficiency of PV panels. A stand-alone PV system is designed to carry out this work. The I–V characteristics have been measured simultaneously for both clean and dusty modules. It has been found that the short circuit current and the maximum output power decrease significantly as dust particles start to accumulate on the panel surface up to a concentration of 1 g/m2, but the rate of decrease is slower for concentrations beyond that value. The reduction in short circuit current in one sample of study is found to be 40%, whereas it is 34% in the maximum output power. In contrast, it is stated that the open circuit voltage is not sensitive to sand dust accumulation. A significant degradation in the efficiency of PV modules is observed for sand dust accumulation up to 1 g/m2. A linear relation has been proposed to correlate the degradation in efficiency to the amount of sand dust accumulated on the module surface. This relation can help PV system designers to reliably predict the effect of sand dust accumulation on PV module efficiency under real environmental conditions.
Article
Air quality data obtained from the Athens air pollution-monitoring network stations during the period 1986-2000 were analysed to determine long-term trends in air quality. The concentration measurements of atmospheric pollutants showed decreasing trends at all monitoring stations. These decreasing trends of nearly all the atmospheric pollutants examined at ground level are attributed to various improvements in pollution sources, such as the renewal of the vehicle fleet and the improvement of fuel quality. Despite the decreasing trends, smoke and carbon monoxide concentration levels in the centre of Athens remained above the EU and WHO limit values for the most part of the examined period. The analysis also showed that the highest nitrogen dioxide concentrations occurred in the centre of Athens. The annual percentages of hourly nitrogen dioxide concentrations (>200 μg/m3) showed increasing trends during the period examined. Generally, also continuously declining violations of all the limits were observed during the greater part of the period.
Chapter
Chapter 9 is about photovoltaic systems. Initially, the general characteristics of semiconductors are given and examine p–n junctions, the photovoltaic effect, and PV cell characteristics. This is followed by a description of photovoltaic panels and examines arrays, and types of PV technology and related equipment, which include batteries, inverters, charge controllers, and peak-power trackers. Then a review of possible applications are presented, which include direct-coupled PV systems, stand-alone applications, grid-connected systems, hybrid-connected systems, and types of applications with a separate section on building-integrated PV systems. This is followed by the methods used to design PV systems and examine electrical loads, absorbed solar radiation, cell temperature, and sizing of PV systems. Subsequently, tilt and yield are considered describing fixed tilt, trackers, shading and tilting versus spacing considerations. Finally, the chapter examines the concentrating PV and the hybrid photovoltaic/thermal (PV/T) systems and their applications including water and air-heating BIPV/T systems.
Article
An investigation of global ultraviolet (GUV), global (G) and diffuse (Gd) solar intensities, continuously recorded over a period of five years at a station in Athens, Greece, and stored on the basis of hourly time intervals since 1996, has revealed the following: (a) UV-global irradiation, associated with the 290-395nm wavelength region, constitutes 4.1% of global solar. (b) UV-global irradiance ranges from an average minimum of 2.4Wm-2 and 3.1% of global solar in January to an average maximum of 45Wm-2 and 7.8%, respectively, in June, both considered at 13:00, solar time. (c) There exists a good correlation among the two dimensionless irradiance ratios GUV/Gd and Gd/G in the form of an exponential relationship. (d) UV-global monthly irradiation data show evidence of temporal variability in Athens, from 1996 to 2000. (e) Anthropogenic and photochemical atmospheric pollutant agents (O3, CO, SO2, NOx, smoke) causing air pollution episodes seem to affect differently solar irradiance components. The main results of analysis (measurements within ±2h from solar noon) indicate that a buildup of O3 and NOx inside the urban Athens plume during cloudless and windless warm days could cause: (i) UV-global irradiance depletion between 5.4% and 14.4%. (ii) Diffuse solar irradiance enhancement up to 38.1%. (iii) Global solar irradiance attenuation ranging up to 6.3%.
Article
The models for photovoltaic (PV) systems currently in ESP-r prove very useful in estimating the electrical and thermal impact of building-integrated photovoltaics. However, while they represent well the impact of photovoltaics on the building's thermal energy balance, they may lack in accuracy in the prediction of the system's energy production. To achieve both goals at once it is suggested to improve the PV models in ESP-r, taking into account all phenomena affecting the power output of PV modules: solar radiation intensity, cell temperature, angle of incidence, spectral distribution, uncertainty in manufacturer's ratings, ageing, mismatch, soil and dirt, snow, partial shading, diodes and wiring. This would provide a more realistic estimate of the probable output of the PV system over its lifetime. It is suggested to implement three models: a simple model based on constant efficiency, a one-diode equivalent model with explicit temperature dependency of the parameters, and the Sandia model for cases when detailed modeling is required.
Article
The tilt angle influences the amount of energy collected by a photovoltaic module. However, representations of these effects on the energy yield and the performance of the PV system are commonly based on the theoretical calculations, whereas there is a lack of experimental investigations. To verify the calculations, an experimental setup has been installed at the Department of Electrical and Computer Engineering, University of Tehran. Some results of this test station, from March, 1999 to January, 2000 are represented in this paper.
Article
The effect of accumulation of dust and particulate matter onto the surface of photovoltaic cells has been experimentally investigated. Five kinds of dust having different physical properties were used. Three of them were limestone particulates with different classes and the other two were cement and carbon particulates. Details on the physical properties of each were obtained through size distribution analysis using an optical microscope. Well-controlled experiments were conducted using a solar simulator as a light source. The dust deposition density (g/m[sup 2]) was precisely determined in each test run. It has been concluded that fine particulates significantly deteriorate the performance of photovoltaic cells, more so than coarser particles. Cement, the main building material which may often present in the atmosphere of urban areas has shown to reduce both the short circuit current and output power when deposited onto the surface of photovoltaic cells. This is due to very small diameter of its particles. Carbon particulates, which are generated from combustion process and emitted from diesel engines among the different dusts used, have shown to result in the worst deterioration of performance of photovoltaic cells, and higher a loss in power output.
Article
Ventilation of photovoltaic (PV) modules installed over or beside a building envelope can reduce the module temperature and increase the electrical conversion efficiency. A computational fluid dynamics (CFD) method has been used to assess the effect of the size of air gap between PV modules and the building envelope on the PV performance in terms of cell temperature for a range of roof pitches and panel lengths and to determine the minimum air gap that is required to minimise PV overheating. It has been found that the mean PV temperature and the maximum PV temperature associated with hot spots decrease with the increase in pitch angle and air gap. The mean PV temperature also decreases with increasing panel length for air gaps greater than or equal to 0.08m whereas the maximum PV temperature generally increases with panel length. To reduce possible overheating of PV modules and hot spots near the top of modules requires a minimum air gap of 0.12–0.15m for multiple module installation and 0.14–0.16m for single module installation depending on roof pitches.
Conference Paper
The most relevant basis for designing photovoltaic systems is their annual energy production, which is also the best metric for monitoring their long-term performance. An accurate array performance model based on established testing procedures is required to confidently predict energy available from the array. This model, coupled with the performance characteristics of other balance-of-system components, provides the tool necessary to calculate expected system performance and to compare actual versus expected energy production. Using such a tool, this paper quantifies the effect of the primary factors influencing the DC-energy available from different photovoltaic module technologies, and contrasts these influences with other system-level factors that often result in significantly less AC-energy delivered to the load than the array is capable of providing. Annual as well as seasonal energy production is discussed in the context of both grid-tied and stand-alone photovoltaic systems.
Article
A recently developed spectral model “SEDES2” is applied to study the effect of variations in solar spectral irradiance on the efficiency of seven particular solar cells. As a new feature, SEDES2 calculates hourly solar spectral irradiance for clear and cloudy skies from readily available site-specific meteorological data. Based on these hourly spectra, monthly and yearly efficiencies for the solar cells are derived. As a key result the efficiencies of amorphous silicon cells differ by 10% between winter and summer months because of spectral effects only. A second intention of this study is to analyse the sensitivity of power and energy rating methods to spectral irradiance but also to total irradiance and cell temperature. As an outcome, a multi-value energy rating scheme applying the concept of “critical operation periods” is proposed.
Article
Possible growth paths for new electricity generation technologies are investigated on the basis of an empirical analysis of past penetration rates. Finding and understanding high market penetration scenarios is relevant to formulating climate change mitigation strategies. The analysis shows that under favorable growth conditions, photovoltaics and wind could produce 15% and 25%, respectively, of world electricity by 2050. Under the same assumptions nuclear power could increase to 41% of world electricity. But it is unlikely that all three technology paths could be realized up to these values simultaneously and therefore the penetration rates presented here should be considered as indicative only. The results show that under positive conditions, an embryonic technology could move as a preferred option into a mainstream energy source within half a century. The introduction of growth constraints reflecting, e.g., severe economic, technical, or political limitations could reduce the above numbers by a factor of up to 2–3. The results indicate a decline in the relative year-to-year growth of new technologies when they have higher market shares. A comparison of the results with other short-term and long-term technology scenarios shows satisfactory agreement.
Article
The progress met in the world market of photovoltaics underlines the maturity of investments realized, guarantees the reliability of the technology utilized and designates the variety of applications in covering the energy demands of both stand-alone and grid connected consumers. Concerning stand-alone systems, the incorporation of photovoltaic systems in water pumping applications is thought to be one of the most popular and ideal uses of solar energy exploitation, especially under the common allegation of coincidence between insolation and water demand. In this study, an attempt to investigate the opportunities of a PV powered water pumping system able to meet additional – apart from the water pump – electricity loads, results in the development of an optimum sizing methodology which is accordingly validated by experimental measurements. From the results obtained, it becomes clear that a properly designed PV-pumping configuration of 610 Wp is capable of covering both the electricity (max 2 kWh/day) and the water (max 400 L/h) management demands of a large variety of remote consumers.
Article
The photovoltaic energy sector is rapidly expanding and technological specification for PV has improved dramatically in the last two decades. This paper sketches the current state of the art and drafts three alternative scenarios for the future, in terms of costs, market penetration and environmental performance. According to these scenarios, if economic incentives are supported long enough into the next ten to twenty years, PV looks set for a rosy future, and is likely to play a significant role in the future energy mix, while at the same time contributing to reduce the environmental impact of electricity supply.
Article
The principal variable to be fixed in the design of a PV cooling duct is its depth, and hence the hydraulic diameter of its cross-section D. Analysis of the flow and heat transfer in the duct under still-air (buoyant flow) conditions, when the temperature rise is greatest, is validated by measurements on a full-scale test rig. It is shown that there is an optimum value of this design variable, such that for an array of length L the minimum temperature occurs when the ratio L/D is about 20. The optimum value is not affected much by other quantities, including the slope of the array.In practical situations, the flow is obstructed by devices across the duct inlet and outlet to exclude insects, birds and rain, and by structural support members crossing the duct interior. It is shown that the latter are no cause for concern, since the effect of the reduction in the flow-rate due to their presence is more than offset by an increase in heat transfer through additional turbulent mixing.It is also shown that array temperatures are strongly reduced by wind effects, which increase both the heat lost from the front surface of the array and by enhancement of the flow in the duct. Though the trends are clear, limitations are encountered in the present state of knowledge in both areas.
Article
We describe a computerized microscope system that has been developed for studying the physics of dust particles which adhere to various kinds of surfaces such as those of solar collectors. The device enables investigators: (1) to obtain the particle size distribution of dust on a surface; (2) to calculate the fraction of surface area covered by dust; (3) to calculate the reduction of optical efficiency (of the solar collector under study) as a function of particle size; (4) to investigate the effect of various kinds of applied force field on the adhesion of dust particles to the surface. Some examples are given for the use of such a measuring system for the study of photovoltaic and solar-thermal collector surfaces.
Article
It is generally recognized that BIPV (building integrated photovoltaics) has the potential to become a major source of renewable energy in the urban environment. The actual output of a PV module in the field is a function of orientation, total irradiance, spectral irradiance, wind speed, air temperature, soiling and various system-related losses. In urban areas, the attenuation of solar radiation due to air pollution is obvious, and the solar spectral content subsequently changes. The urban air temperature is higher than that in the surrounding countryside, and the wind speed in urban areas is usually less than that in rural areas. Three different models of PV power are used to investigate the effect of urban climate on PV performance. The results show that the dimming of solar radiation in the urban environment is the main reason for the decrease of PV module output using the climatic data of urban and rural sites in Mexico City for year 2003. The urban PV conversion efficiency is higher than that of the rural PV system because the PV module temperature in the urban areas is slightly lower than that in the rural areas in the case. The DC power output of PV seems to be underestimated if the spectral response of PV in the urban environment is not taken into account based on the urban hourly meteorological data of Sao Paulo for year 2004.
Article
Ten out of the 12 new EU members, used to belong to the so-called "former eastern block", with a post WWII environmental policy radically different from the tendencies followed in Western Europe. The lack of conservation regulations has resulted in a rather harmful industrialization, regarding natural resources and environmental quality. While air pollution transfer is a phenomenon of transboundary level, there is a particular interest in examining the contribution of the new EU member states to the environmental pressure faced by the older member states and vice versa. The current study utilises the official data for almost 20 years published by the European Monitoring and Evaluation Program concerning the transboundary transfer of NOx and SO2 in order to analyse the situation and discuss the present and future environmental policy regarding air pollution.
Article
The present study analyzes PM10 concentration data collected by the Greek air quality monitoring network at 8 sites over the Greater Athens Area, for the period of 2001–2004. The primary objectives were to assess the degree of compliance with the EU-legislated air quality standard for PM10 and also provide an overall statistical examination of the factors controlling the seasonal and spatial variation of concentrations, over the wider urban agglomeration. Daily concentrations, averaged over the whole study period, ranged between 32.3 and 60.9 μg m⁻³. The four-year average concentration of PM10 at five sites exceeded the annual limit value of 40 μg m⁻³, while most of the sites surpassed the allowed percentage of exceedances of the daily limit value (50 μg m⁻³), for each of the four years.
Experimental study for the determination of the maximum energy yield of a photovoltaic station during the winter period
  • C Gitersos
  • J K Kaldellis
Gitersos C, Kaldellis JK. (Supervisor). Experimental study for the determination of the maximum energy yield of a photovoltaic station during the winter period. Diploma Thesis D-90, Dept of Mechanical Engineering, TEI of Piraeus, Greece; 2009.
Special program of photovoltaic system growth in buildings and specifically in roofs and rooftops
  • Hellenic Ministry
  • Development
Hellenic Ministry of Development. Special program of photovoltaic system growth in buildings and specifically in roofs and rooftops. Available at: http:// www.ypan.gr.
Photovoltaics on flat roofs: energy considerations, www.ScienceDirect.com. on-line available
  • A Bayod-Rújula Aa
  • Martínez-Gracia
Bayod-Rújula AA, Ortego-Bielsa A, Martínez-Gracia A. Photovoltaics on flat roofs: energy considerations, www.ScienceDirect.com. on-line available (15/ 05/2010) in.
Renewable energy-sources for fuels and electricity
  • T B Johansson
  • H Kelly
  • Akn Reddy
  • R H Williams
Johansson TB, Kelly H, Reddy AKN, Williams RH. Renewable energy-sources for fuels and electricity. 1st ed. Washington: Island Press; 1992.
Laboratory applications of renewable energy sour-ces Athens: Stamoulis
  • Kaldellis Jk Ka
Kaldellis JK, Kavadias KA. Laboratory applications of renewable energy sour-ces. 1st ed. Athens: Stamoulis; 2000.
Critical evaluation of solar collector market in Greece using long-term solar intensity measurements
  • J K Kaldellis
  • D S Vlachou
  • P S Koronakis
  • J E Garofalakis
Kaldellis JK, Vlachou DS, Koronakis PS, Garofalakis JE. Critical evaluation of solar collector market in Greece using long-term solar intensity measurements. Balkan Physics Letters 2001;
Pollution effect on PV system efficiency
  • L Kappos
  • I Ntouros
  • I Palivos
Kappos L, Ntouros I, Palivos I. Pollution effect on PV system efficiency. In: Proceedings of the 5th National Conference on Soft Energy Forms, Athens; 1996.
Analysis of factors influencing the annual energy production of photovoltaic systems
  • D L King
  • W E Boysen
  • J A Kratochvil
King DL, Boysen WE, Kratochvil JA. Analysis of factors influencing the annual energy production of photovoltaic systems. In: Proceedings of the 29th IEEE PVSC, New Orleans; 2002, 1356e61.
Laboratory applications of renewable energy sources
  • J K Kaldellis
  • K A Kavadias
Kaldellis JK, Kavadias KA. Laboratory applications of renewable energy sources. 1st ed. Athens: Stamoulis; 2000.