This paper presents a comprehensive review on solar tracking systems and their potentials in solar energy applications. The paper overviews the design parameters, construction, types and drive system ...techniques covering different usage application. There are two main solar tracking systems types that depending on their movement degrees of freedoms are single axis solar tracking system and dual axis solar tracking system, which are addressed in the recent studies. The solar tracker drive systems encompassed five categories based on the tracking technologies, namely, active tracking, passive tracking, semi-passive tracking, manual tracking, and chronological tracking. The paper described the various designs and components of the tracking systems. There are 42.57% of the studies discussed and presented single axis tracking systems while 41.58% of these studies to the dual axes tracking systems. In the recent research studies, the most common solar tracker drive type was active tracker by 76.42% usage in applications while in the second most impact type is the chronological solar tracker by 7.55%. Furthermore, in the solar tracking techniques, Azimuth and altitude tracking achieved 16.67% in usage, Horizontal tracking by 16.67%, Azimuth tracking by 10%, and polar tracking by 4.44%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•A novel method for solar power probabilistic forecasting is proposed.•The forecast accuracy does not depend on the nominal power.•The impact of climatology on forecast accuracy is evaluated.
The ...energy produced by photovoltaic farms has a variable nature depending on astronomical and meteorological factors. The former are the solar elevation and the solar azimuth, which are easily predictable without any uncertainty. The amount of liquid water met by the solar radiation within the troposphere is the main meteorological factor influencing the solar power production, as a fraction of short wave solar radiation is reflected by the water particles and cannot reach the earth surface. The total cloud cover is a meteorological variable often used to indicate the presence of liquid water in the troposphere and has a limited predictability, which is also reflected on the global horizontal irradiance and, as a consequence, on solar photovoltaic power prediction. This lack of predictability makes the solar energy integration into the grid challenging. A cost-effective utilization of solar energy over a grid strongly depends on the accuracy and reliability of the power forecasts available to the Transmission System Operators (TSOs). Furthermore, several countries have in place legislation requiring solar power producers to pay penalties proportional to the errors of day-ahead energy forecasts, which makes the accuracy of such predictions a determining factor for producers to reduce their economic losses. Probabilistic predictions can provide accurate deterministic forecasts along with a quantification of their uncertainty, as well as a reliable estimate of the probability to overcome a certain production threshold. In this paper we propose the application of an analog ensemble (AnEn) method to generate probabilistic solar power forecasts (SPF). The AnEn is based on an historical set of deterministic numerical weather prediction (NWP) model forecasts and observations of the solar power. For each forecast lead time and location, the ensemble prediction of solar power is constituted by a set of past production data. These measurements are those concurrent to past deterministic NWP forecasts for the same lead time and location, chosen based on their similarity to the current forecast and, in the current application, are represented by the one-hour average produced solar power.
The AnEn performance for SPF is compared to a quantile regression (QR) technique and a persistence ensemble (PeEn) over three solar farms in Italy spanning different climatic conditions. The QR is a state-of-the-science method for probabilistic predictions that, similarly to AnEn, is based on a historical data set. The PeEn is a persistence model for probabilistic predictions, where the most recent 20 power measurements available at the same lead-time are used to form an ensemble. The performance assessment has been carried out evaluating important attributes of a probabilistic system such as statistical consistency, reliability, resolution and skill. The AnEn performs as well as QR for common events, by providing predictions with similar reliability, resolution and sharpness, while it exhibits more skill for rare events and during hours with a low solar elevation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This paper presents a review of tilt angle and azimuth angles in solar energy applications. The paper involves an overview of design parameter, applications, simulations and mathematical techniques ...covering different usage application. The number of references analysing the tilt angle deployment in the context of the research papers of the different countries currently having operations in solar systems is much more significant. Different kinds of models and test methods of optimum tilt angle in different solar systems have been developed since 1956 which can be distinguished by their particular mathematical models or tracking techniques as shown in the latest researches. The mathematical models allows the calculation of different parameters of the solar radiation, the angle of inclination, and the optimum tilt angle of the collecting surface and the effects acting on the system.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The conversion of solar energy into electricity is a viable response to address most of world's energy problems. Among the parameters affecting the performance of both photovoltaic (PV) cells and ...concentrating solar power (CSP) systems include their orientation and tilt angle with respect to the sun. Solar trackers (ST) are ideal devises for efficiency improvement. This paper aims to review the most commonly used ST and identify the systems that offer benefits such as greater efficiency, greater tracking accuracy, easy installation and cost effectiveness.
There are mainly two types of ST viz. single and double axis ST. The optimization of these devices requires cumbersome specifications to avoid potential tracking errors that often lead to their poor performance. These specifications cannot be fulfilled by simple tracking methods due to different sources of tracking errors such as the misalignment of the tracking fixture, the level of pollution of the area, the shading of the sensors, the types of control schemes involved, the auxiliary units of the system, the lack of maintenance as well as the imperfection and power mismatch of connecting grids.
The study reveals that double axis ST in form of polar-axis and azimuth/elevation featuring the solar movement models and the dynamic closed loop feedback control are the most effective and generally give more than a 40% improvement in energy return compared to fixed PV panels. Moreover, large systems significantly reduce the costs and save on materials. The energy consumed by the moving fixtures is mostly low (2–5% of the collected energy) but this could be higher if no optimization is performed. Lastly, all the hardware and software energy saving parameters must be optimized right from the early stages of the development of the system to prevent materials wastage and the energy over-consumption by the tracking units.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Solar collectors and Photovoltaic panels are the most common applications of solar energy. Although how to increase the efficiency of these systems in different ways has been vastly studied and ...analyzed, the effect of dust accumulation on panel’s and collector’s efficiency has been largely ignored. To overcome this deficit, an experiment was developed in Isfahan, Iran, to investigate the factors affecting dust accumulation and their effects on the transmission coefficient of glass. The results indicate factors such as installation tilt, azimuth angle, dominant wind direction and the time in which samples are placed within the environment, are related to dust accumulation density on surface and transmission coefficient reduction. Up to 25% decline in the transmission coefficient caused by the accumulation of dust on the surface was observed during the 70-day test period. Given that the dust fall density is strictly depended on weather conditions during the test period, unlike previous studies, in this article the transmission reduction relation, instead of time is derived in terms of dust accumulation density on the surface. This equation is generalized and applicable to other regions and even different weather conditions.
•The factors affecting dust accumulation on glass cover were investigated.•The effect of settlement of dust on the transmission coefficient of glass was investigated.•A generalized correlation form was introduced to predict dust accumulation effect in other regions and weather conditions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Key global energy, environmental and sustainability targets are closely related to the development of Renewable Energy Sources (RES). This includes reduction of Greenhouse Gas emissions and safe ...energy provision in a sustainable manner. The integration of RES in the energy mix needs to overcome the technical challenges that are related to grid's operation. Therefore, there is an increasing need to explore approaches where different RES will operate under a synergetic approach. A straightforward way to achieve that is by optimizing the complementarity among RES systems both over time and spatially. The present article developed a methodology that examines the degree of time complementarity between small hydropower stations (SHPS) and adjacent solar PV systems (SPVS). The methodology builds on an optimization algorithm that associates hydrological with solar irradiation information. In particularly, the algorithm examines possible alterations on the PV system installation (azimuth, tilt) that increase the complementarity, with minor compromises in the total solar energy output. The methodology has been tested in a case study and the outcome indicated that a compromise of 10% in the solar energy output (90% threshold) may result in a significant increase of the complementarity (66.4%).
•We explained and analyzed the need for increased complementarity between Renewable Energy systems.•We developed a methodology that assesses the complementarity between small hydropower and solar PV systems.•An optimization algorithm was developed to maximize complementarity, with small compromises in the solar energy output.•The algorithm uses cloud-based information available online in PVGIS platform (developed in our Institute).•In the case study the complementarity increased by 66.4%, with 10% compromise in solar energy production.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•A new method for rooftop PV potential assessment is presented.•It allows highly detailed analyses without having to rely on 3D city models.•Image recognition and machine learning techniques are ...applied on aerial images.•The method is applied to Freiburg, Germany and validated against a 3D model.
The local generation of renewable electricity through roof-mounted photovoltaic (PV) systems on buildings in urban areas provides huge potentials for the mitigation of greenhouse gas emissions. This contribution presents a new method to provide local decision makers with tools to assess the remaining PV potential within their respective communities. It allows highly detailed analyses without having to rely on 3D city models, which are often not available. This is achieved by a combination of publicly available geographical building data and aerial images that are analyzed using image recognition and machine learning approaches. The method also employs sophisticated algorithms for irradiance simulation and power generation that exhibit a higher accuracy than most existing PV potential studies. The method is demonstrated with an application to the city of Freiburg, for which a technical PV electricity generation potential of about 524GWh/a is identified. A validation with a 3D city model shows that the correct roof azimuth can be determined with an accuracy of about 70% and existing solar installations can be detected with an accuracy of about 90%. This demonstrates that the method can be employed for spatially and temporally detailed PV potential assessments in arbitrary urban areas when only public geographical building data is available instead of exact 3D city model data. Future work will focus on methodological improvements as well as on the integration of the method within an urban energy system modeling framework.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The efficiency of the photovoltaic (PV) system is directly proportional to the solar energy. The maximum efficiency from the PV systems can be achieved if the panel is kept perpendicular to the ...direction of the radiations of sun. Hence, in order to achieve maximum concentration, radiation and efficiency of the PV cell, tracking of the position of the sun with accuracy is extremely important. The various methods of sun tracking system have been discussed which includes two axes, one axis, polar axis, open loop, closed loop, hybrid model, azimuth and tilt roll mechanism. The comparison of existing solar tracking systems and methods has also been discussed. In this paper, various existing solar tracking systems in terms of the controller used like PLC, microcontroller, FPGA to design the system and their economic assessment have been studied. It is concluded that two axis solar tracking systems has more power gain with respect to fixed systems. The microcontroller based tracking system with same size, capacity and location as of PLC based systems are more economic.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Evaluating techno-economic role of type of PV trackers in a hybrid PV-PSH system.•Comparing different PV sun-trackers in terms of various techno-economic criteria.•Optimal design of a PV- PSH system ...based on fluctuating power demand.•Proving superiority of a PV-PSH system over the common PV-battery system.•Presenting a novel optimization approach for optimal design of a PV-PSH system.
The main aim of this study is to evaluate the techno-economic role of the PV tracking technology in a hybrid photovoltaic-pump storage hydroelectric (PV-PSH) standalone power system. In this regard, a multi-objective optimization procedure is developed for the optimal design of a PV-PSH system and the developed procedure is separately implemented for the different types of PV tracking technologies such as horizontal and fixed-tilt panels (without any sun tracker), East-West oriented single-axis tracking, fixed-tilt azimuth tracking and dual-axis tracking systems. A coastal area in the south of Iran is considered as the case study; investment cost and loss of power supply probability (LPSP) are considered as the objective functions. Moreover, number of PV modules, turbine capacity, pipes diameters, and the volume, installation height and depth to diameter ratio of reservoir constitute the set of design variables and NSGAII is employed as the optimization algorithm. The results show that for the present case study, the fixed-tilt azimuth tracking technology leads to the minimum system cost with a suitable certainty under different LPSP values. Moreover, it results in the greatest match between the demanded and supplied power profiles. The results also illustrate that the appropriate selection of sun tracking technology in a hybrid PV-PSH system can lead to a savings of up to 18.2%. Finally, the economic superiority of the PV-PSH system over the common PV-battery system is investigated and proved for the case study.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Variation in temperature with time computed for various depths of PCM container.•Optimum depth of PCM container found out to maintain PV at low temperature.•Effects of operating conditions on the ...optimum depth of PCM container analysed.•Optimum depth for various daily solar radiation levels computed.
The rise in the temperature of photovoltaic (PV) leads to decrease in the solar to electricity conversion efficiency. This paper presents a simulated study to investigate the thermal management of the PV panel using phase change material (PCM). It is found that once the PCM is fully melted, the rate of heat extraction by PCM decreases and, thus, the PV temperature starts increasing rapidly. In literature, the studies related to the performance analysis of the PV-PCM system are available. However, the optimization of the PCM quantity to cool the PV in various operating conditions and solar radiation levels is not available. Thus, it has been carried out in the presented work. The effects of the operating conditions (wind azimuth angle i.e. wind direction, wind velocity, melting temperature of PCM and ambient temperature) on the optimum depth of the PCM container have been analysed. The results show that as wind azimuth angle increases from 0° to 90°, the optimum depth of the PCM container (to maintain the PV at lower temperature) increases from 3.9 cm to 5.3 cm for ∑IT = 5 kWh/m2/day and from 2.4 cm to 3.2 cm for ∑IT = 3 kWh/m2/day for the chosen parameters.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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