Optimum Tilt Angle Research Articles

Evaluation of Optimal Occasional Tilt on Photovoltaic Power Plant Energy Efficiency and Land Use Requirements, Iran

The paper studies the optimum panel horizontal orientation angle toward the Sun and the optimum time interval of the panel’s movement. The optimum time intervals or panel movement can change the rate of input energy to the panel surface in Iran. For this purpose, a neural network has been trained to estimate the intensity of solar radiation in Iran. After model validation, the intensity of solar radiation has been estimated by selecting adequate geographical regions. Based on the intensity of sunlight, Iran has been divided into ten regions. In these regions, 40 cities have been randomly selected to study the effect of the panel’s angle variations within appropriate time intervals, as well as equal time intervals. The results show that the choice of the mounting system with the possibility of five angles’ implementation can increase the amount of solar energy between 3.9% and 7.4%. Compared to this number of angles at the equal time intervals, the amount of incoming solar energy has increased by 3% to 7%. In the first and second cases, the area of the power plant increases by about 12% to 24% compared to the yearly optimum tilt angle. Moreover, the amount of radiation incoming to the panel with the optimum operating angle is in alignment with the results of PVsyst software.

Performance analysis outcome of a 19‐MWp commercial solar photovoltaic plant with fixed‐tilt, adjustable‐tilt, and solar tracking configurations

AbstractPhotovoltaic (PV) plants are generally installed at optimum tilt angle for a location or using sun tracking for enhancing energy generation potential. The objective of the present study is to assess the practicability of these techniques for large commercial plants along with determining expected uncertainty in simulated energy yield estimation. In this study, performance analysis of a 19‐MWp (17‐MWac) PV plant is carried out which is installed in India with fixed‐tilt (FT), seasonal adjustable‐tilt (AT), and horizontal single‐axis solar tracking (HSAT) configurations. This study is the first‐time comparative power enhancement analysis of these three different configurations under real outdoor conditions for a single large scale power plant at one location. The operation and maintenance issues of these configurations are also analyzed. A reliability analysis of linear actuator of the industrial solar tracking system is carried out as the actuator is a critical part of the solar tracking system of the power plant. Major results of the study are annual performance ratio 79% (FT), capacity factors = 19% (FT), 20% (AT), and 22% (HSAT) respectively, final yields (Yf) = 4.58 h/day (FT), 4.85 h/day (AT), and 5.28 h/day (HSAT). The energy yield simulations are done on two widely used PV design software: PVSyst and PVSOL and results are analyzed in detail. The accuracy of predicted data is validated and found to be within acceptable limits of uncertainty. The results of this study are compared with previous studies.

Validation of thermal models to predict the productivity and heat transfer coefficients for passive solar still with different nanoparticles

ABSTRACT The study aims to predict the internal heat transfer coefficient (HTC) and distillate output of single slope solar still with and without nanoparticles for 41° tilt angle of glass cover with 4 cm water depth using various existing thermal models. The experiment is conducted in the winter season at the Solar Lab of MITS, Gwalior campus, M.P., India. After experiment on SSs at three different tilt angles (11°, 26°, and 41°) and three different water depths (4 cm, 5 cm, and 10 cm) it is observed that for winter season, the optimum tilt angle of glass cover is 41° and optimum water depth is 4 cm. Therefore, in this paper, six different thermal models have been validated at optimal parameters. The yield predicted using different thermal models is validated with the experimental yield. Statistical tool correlation coefficient (r) and root mean square percentage deviation (e) are calculated to show the error between experimental and predicted values. It is noticed that the value of correlation coefficient (r) is almost 0.99 for all models and for all cases. Kumar and Tiwari model shows the better agreement with the experimental value, with the lowest yield percentage deviation of 8.41%, 9.52%, and 9.89% for solar still with ZnO nanofluids, CuO nanofluids, and without nanoparticles, respectively. The distillate obtained through the CuO nanofluids and ZnO nanofluids is about 41.11% and 9.75% higher than the water without nanoparticles for 41° tilt angle of glass cover and 4 cm of water depth.

A comparative study between racking systems for photovoltaic power systems

We present a comparative study of the different racking systems used in photovoltaic power systems, with a new methodology for determining the total energy produced by each one under usual weather conditions (not clear-skies). In systems without solar tracker, the tilt angle is a major factor contributing to the energy production, and its optimization is essential. We study the effect of tilt update frequency (daily, monthly, or constant) on the total irradiation received by a plane surface, and present a method for computing the optimal tilt angle, which we validate using previous studies. This method is easily implemented, accurate, and valid for any location. We compare all the systems with the most energy-productive one, the dual-axis tracker, in two ways: with respect to energy production, and to levelized cost of energy, both in 39 cities around the World. The results provide a new insight on the relative and objective value of trackerless systems, and some remarkable properties arise, which may be relevant in budgetary consideration.

A New Model for Estimation of Energy Extraction from Bifacial Photovoltaic Modules

The energy yield from bifacial solar photovoltaic (PV) systems can be enhanced by optimizing the tilt angle. Bifacial modules boost the energy yield by 4% to 15% depending on the module type and ground reflectivity with an average of 9%. The selection of tilt angle depends on several factors, including the geographical location, weather variation, etc. Compared to the variable tilt angle, a constant angle is preferred from the point of view of the cost of installation and the cost of maintenance. This paper proposes a new method for analysing bifacial modules. A simpler rear-side irradiance model is presented to estimate the energy yield of a bifacial solar photovoltaic module. The detailed analysis also explores the optimum tilt angle for the inclined south–north orientation to obtain the maximum possible yield from the module. Taking four regions into account, i.e., Kharagpur, Ahmedabad, Delhi, and Thiruvananthapuram, in the Indian climate, we studied several cases. The Kharagpur system showed a monthly rear irradiance gain of 13%, and the Delhi climate showed an average performance ratio of 19.5%. We studied the impact of albedo and GCR on the tilt angle. Finally, the estimated model was validated with the PVSyst version 6.7.6 as well as real field test measurements taken from the National Renewable Energy Laboratory (NREL) located in the USA.

Solar Energy Potential in Horn of Africa: A Comparative Study Using Matlab/Simulink

Geographically, the Horn of Africa is one of the regions that the Equator passes over, providing the opportunity for vigorous solar energy. However, despite the enormous solar energy resources, more than half of the region, 132 million populations have not yet access to electricity. This study presents an overview of the potential of solar energy in the region. Then review the current solar energy status and policies related to it. A Matlab/Simulink model is developed to show the comparative analyses of the solar radiation graphically on the photovoltaic modules and electricity outputs for the Horn of African countries' capitals. As a result of the simulation model, Ethiopia-Addis Ababa receives the highest annual solar radiation of 2915.03 kWh/m2-year while Eritrea-Asmara with the lowest annual solar radiation of 2198.47 kWh/m2-year. The annual electrical output of the photovoltaic modules in Ethiopia-Addis Ababa is the highest with 286.685 kWh/year and Eritrea-Asmara 216.214 kWh/year as the lowest in the region. The number of photovoltaic modules and the optimum tilt angles are calculated. For Ethiopia-Addis Ababa, the lowest photovoltaic module number is 10, and the optimum PV tilt angle is 11.163°. For Eritrea-Asmara, the highest photovoltaic module number is 14, with a tilt angle of 15.397°.

A Theoretical Optimum Tilt Angle Model for Solar Collectors from Keplerian Orbit

Solar energy has been extensively used in industry and everyday life. A more suitable solar collector orientation can increase its utilization. Many studies have explored the best orientation of the solar collector installation from the perspective of data analysis and local-area cases. Investigating the optimal tilt angle of a collector from the perspective of data analysis, or guiding the angle of solar collector installation, requires an a priori theoretical tilt angle as a support. However, none of the current theoretical studies have taken the real motion of the Sun into account. Furthermore, a complete set of theoretical optimal tilt angles for solar energy is necessary for worldwide locations. Therefore, from the view of astronomical mechanics, considering the true orbit of the Sun, a mathematical model that is universal across the globe is proposed: the Kepler motion model is constructed from the solar orbit and transformed into the local Earth coordinate system. After that, the calculation of the optimal tilt angle solution is given. Finally, several examples are shown to demonstrate the variation of the optimal solar angle with month and latitude. The results show that for daily fixed solar collectors, the altitude angle of the collector should be about 6° above the noon solar altitude angle in summer and 6° lower in winter. For annual fixed collectors, the tilt angle should be slightly higher than the latitude. In summary, this study demonstrates that when a location is specified, this model can be used to calculate the theoretical optimum tilt angle of solar collectors for that position.

Optimum Height and Tilt Angle of the Solar Receiver for a 30 kWe Solar Tower Power Plant for the Electricity Production in the Sahelian Zone

This work investigated the prediction of the optimum height and tilt angle of the solar receiver of a 30 kWe solar tower power plant for the electricity production in the Sahelian zone. Initially, the solar field is sized to determine the total reflecting surface area of the mirrors and the number of heliostats. A PS10-like radially staggered heliostat field is used to design the heliostat layout in the field using a Matlab code. The concentrated solar flux at the input of the receiver was determined using Soltrace software by the Monte Carlo ray tracing (MCRT) method. The sizing results show that the total reflecting surface area is 350 m2 for an optical efficiency of 76.4% and a reference DNI of 600 W/m2. The solar field layout indicates 175 heliostats of 2 m2 surface area and 1.5 m height each. The simulation results show that the optimum height and tilt angle of the solar receiver are 26 m and 65°, respectively.

Improvement of Stand-Alone Solar PV Systems in the Maputo Region by Adapting Necessary Parameters

With the energy crisis and the constant blackout in the Mozambique Power Company grid, the option of applying solar photovoltaic (PV) systems has been one of the most used alternatives in the neighborhoods of the Maputo region. However, inefficient power delivery caused by unproper sizing and installation of stand-alone solar PV systems has been contributing to the low utilization of solar energy potential in the Maputo region. The optimal sizing and installation of the solar PV system is addressed to evaluate the influence of installation and operation parameters on the power output of PV modules. In this topic, PV modules parameters such as cell temperature, the module’s slope and azimuth angles, the losses caused by excessive heating of the module cells, shadows and dust on the PV module and the cooling process at the back of the module are assessed in order to find out the consequence of inadequate installation and operation parameters of solar PV systems in the Maputo region. The proper sizing and installation of the stand-alone solar PV system is fundamental to guarantee the continuous and efficient supply of power and, thus, different tools and techniques have been applied. This study will deal with the hybrid optimization of multiple energy resources (HOMER) and system advisor model (SAM), to size and improve power generation of solar PV systems. This study concluded that for the Maputo region, the optimal tilt angle is 23 ± 2° and the azimuth angle is 11 ± 2°. In addition, for optimization of the tilt and azimuth angles, it also examined the effect of module backside ventilation and proved that the system’s power generation increases with the rise of spacing between the module and the wall, since the strategy prevents the decline of the module cells efficiency. However, the maximum recommended spacing between the PV module and the mounting wall is about 0.4 m, since an effort to increase the spacing up to this level results in an insignificant growth of power output.

A new approach to determine the optimum tilt angle and orientation of solar collectors in mountainous areas with high altitude

In mountainous areas with high altitude, abundant sunshine, and low cloud cover presence, the complex terrain is the key factor affecting the spatial and temporal distribution of solar energy. However, at present, when seeking the optimal installation angles of solar collectors in mountainous areas, the terrain shading effect is not fully considered, which seriously restricts the solar energy application. To accurately calculate the optimal angles of solar collectors in mountainous areas with high altitude, the concept of viewshed is introduced in the study to analyze the terrain shading effect quantitatively. By double integrating the solar irradiance over the viewshed, the potential solar irradiation under the terrain shading is predicted to detect the solar collectors’ optimal tilt angle and orientation. Then, validation of the method is performed by comparing with the meteorological data of a typical meteorological year and the prediction values of existing radiation models. Besides, Batang county is selected as a case to demonstrate the application of the method. Compared with the recommended angles of the current standard, after considering the terrain shading effect, the optimized annual and monthly optimal angles can increase the solar energy collection by 238.72 kWh/m2 (9.73%) and 398.33 kWh/m2 (16.24%) per year respectively.

A two-stage multi-objective optimization method for envelope and energy generation systems of primary and secondary school teaching buildings in China

A comfortable indoor environment plays an important role in improving students' learning efficiency and health. How to optimize the design of primary and secondary school education buildings to achieve a comfortable indoor environment, considering both energy and cost is a considerable challenge. This paper proposes a two-stage multi-objective optimization method based on a meta-model to obtain the optimal design scheme for primary and secondary school education buildings, based on daylighting, thermal comfort, energy savings and economy. The method has two stages: building envelope optimization and building generation system optimization. In the stage of building envelope optimization, an artificial neural network (ANN) model coupling optimization algorithm is used to optimize the building envelope. The performances of the non-dominated sorting genetic algorithm II (NSGA-II) and multi-objective particle swarm optimization (MOPSO) algorithm are compared in the optimization process. In the stage of building generation system optimization, the design optimization of the building photovoltaic generation system is studied. Finally, the effectiveness of the two-stage optimization method is verified by a typical teaching building in Nanjing. The results show that the optimal scheme set of building envelope design can be obtained by this optimization method, and the optimal tilt angle and azimuth angle of the photovoltaic generation system are 30° and 210°, respectively. The minimum payback periods of the photovoltaic generation system are 11.75 years and 9.32 years under the policy of selling electricity that is not permitted and selling electricity that is permitted, respectively.

Optimising monthly tilt angles of solar panels using particle swarm optimisation algorithm

This paper presents an intelligent computational method using the PSO (particle swarm optimisation) algorithm to determine the optimum tilt angle of solar panels in PV systems. The objective of the paper is to assess the performance of this method against conventional methods of determining the optimum tilt angle. The method presented here can be used to determine the optimum tilt angle at any location around the world. In this paper, it was applied to Brunei Darussalam, and succeeded in computing monthly optimum tilt angles, ranging from 34.7ᵒ in December to -26.7ᵒ in September. Results showed that changing the tilt angle every month, as determined by the PSO algorithm, increased annual yield by: (i) 5.94%, compared to keeping it fixed at 0ᵒ, (ii) 8.65%, compared to Lunde’s method and (iii) 17.31%, compared to Duffie and Beckman’s method. Benchmark test functions were used to compare and evaluate the performance of the PSO algorithm with the artificial bee colony (ABC) algorithm, another metaheuristic algorithm. The tests revealed that the PSO algorithm outperformed the ABC algorithm, exhibiting lower root mean square error and standard deviation, better convergence to the global minimum, more accurate location of the global minimum, and faster execution times.

English

This paper deals with finding the optimum tilt angle of solar panels for solar energy applications. The objective is to maximize the output electrical energy of the photovoltaic (PV) modules. A mathematical model was used to determine the optimum tilt angle of solar collectors in Senegal on a daily and monthly basis, as well as for a specific period. Then, the configuration of the optimum tilt angle was analyzed by studying four specific cases in different typical climatic zones in Senegal. On a horizontal plane, the sun spends more time in the south than in the north. This means that in Senegal, the optimum tilt angle is often set equal to latitude. On the other hand, the optimum latitude angle is only for annual optimization. This study shows that the optimum tilt angle equal to latitude does not produce maximum output. For monthly optimum tilt angle, only the month of November gives tilt optimum angles equal to latitude. It is preferable to change the tilt angle of solar conversion systems monthly instead of fixing them, to gain more energy.   Keys words: Solar energy, solar panels, tilt angle, orientation solar panel, latitude, geometry.

Güneş Enerji Panellerindeki Optimum Eğim Açısının Verime Etkisinin İncelenmesi

Fosil yakıtlardan elde edilen enerji çevre ve insan sağlığını olumsuz yönde etkilemektedir. Dünyada enerji tüketimine bağlı olarak gelişen olumsuz etkiyi azaltmak için Uluslararası Yenilenebilir Enerji Ajansı tarafından yeni tedbirler uygulanmaya başlanmıştır. Bu tedbirlerin başında güneş enerjisine dayalı elektrik üretimi gelmektedir. Bu çalışma, Kayseri’de yapılacak olan güneş enerjisi yatırımlarında kullanılan güneş panellerinin güneş ışınımından daha iyi faydalanmalarını sağlamak için yapılmıştır. Yapılan çalışmada, panellerin aylık, mevsimlik ve altı aylık performansları ile optimum eğim açısının tespit edilmesi amaçlanmıştır. Çalışma kapsamında, güneş ışınımı tespitinde Fotovoltaik Coğrafi Bilgi Sistemi (PVGIS), eğim açılarının tespitinde ise PVGIS ve Hottel & Woertz (HW) metotları kullanılmıştır. Hesaplamalar sonucunda; PVGIS ve HW metotları arasındaki açı farkının yaz aylarında 10,6°’ye kadar çıktığı, yılın son dört ayında ise birbirleriyle aynı değerleri aldığı görülmüştür. Kayseri’de güneş panellerinin her ay farklı sabit bir optimum eğim açısı ile konumlandırılması durumunda 1852,3 kWh/m2 maksimum güneş ışınımı elde edilmiştir. Yıllık 29,5°’lik eğim açısıyla konumlandırılan güneş paneline göre; aylık, mevsimsel ve altı aylık olarak değiştirilen panel eğim açılarındaki verimin sırasıyla yılda %4,11, %3,25 ve %2,99 arttığı tespit edilmiştir. Aylık optimum eğim açısı ile konumlandırmanın büyük avantaj sağladığı anlaşılmıştır. Mevsimsel ve altı aylık optimum eğim açıları karşılaştırıldığında ise verim farkı yüzde 0,26 olduğu saptanmıştır. Bu farkın az olması, güneş panellerinin yılda iki kez (altı aylık) eğim açısını değiştirerek konumlandırmasının uygun olacağını göstermiştir.

High accuracy disturbance observer-based agile attitude stabilization with three-dimensional MSW

PurposeThe purpose of this paper is agile attitude control design with the novel three-dimensional (3D) magnetically suspended wheel (MSW) that is the preferred type for agile maneuvering compared to conventional control moment gyro due to frictionless, low vibration and long lifetime. This system does not require a separate steering law for pyramid arrangement to derive tilt angles. It is also conducting an agile maneuver with high accuracy despite the high-frequency disturbances.Design/methodology/approachIn this paper, a disturbance observer-based attitude stabilization method is proposed for an agile satellite with a pyramid cluster of the novel 3D magnetically suspended wheel actuator. This strategy includes a disturbance observer and a linear quadratic regulator controller. The rotor shaft deflection of MSW is actively controlled to reduce vibration and producing gyro torque. The deflection angle of the pyramid cluster MSWs considered as control parameters. The closed-loop stability is proved by using the Lyapunov strategy. The efficiency and performance of the offered method verified by numerical simulation via MATLAB/SIMULINK software.FindingsAccording to simulation results, the disturbance observer-based control controller stabilized the system with high accuracy and optimal tilt angles without any extra steering law equation. Hence, the system speed is increased, and the system error is minimized without separate steering law.Practical implicationsThe magnetically suspended wheel is a new kind of inertia actuator for attitude control that has several benefits such as frictionless, high-speed rotor, clean environment and low vibration compared to the traditional wheel. It has complex nonlinear dynamics that cause have complicated controller design. The proposed strategy stabilizes the system and conducting an agile maneuver with high precision despite the high-frequency disturbances. It is applicable for some missions requiring high accuracies, like Earth observation and the solar observation mission that require a very accurate pointing control and a long lifetime.Originality/valueThis paper is the initial paper to design a pyramid array for magnetically suspended wheels. Compared to other research, this method doesn’t need a separate steering law of the MSWs cluster and presented optimal tilt angles with less computational. Also, it designs a disturbance observer-based controller for this system that proposed high accuracy and agile stabilization.

Correlation formulation for optimum tilt angle for maximizing the solar radiation on solar collector in the Western Himalayan region

Solar tracking devices are efficacious in maximizing solar irradiation collection. However, higher price makes these systems less frequently used. As an alternative, optimum tilt angle estimation has the advantage that it does not involve tracking cost expenditure. In this study, optimum tilt angles for different months have been computed for Hamirpur, Himachal Pradesh, India (L 31° 42′ N). Several mathematical models and statistical tools have been employed to forecast the monthly optimum tilt angles for the selected site. Different scenarios have been presented by considering five, four, three, and two annual adjustment models to increase the practical usage of the estimated optimum tilt angles. Additionally, cost-benefit analysis has also be performed on the PV panels. Based on the results, it has been concluded that model M − 11, with three annual adjustments, stipulates maximum benefits over the other models. This study can serve as fundamental guidance for setting up solar energy plants in this specified region with the highest efficiency.

Solar energy harvesting on building’s rooftops: A case of a Nigeria cosmopolitan city

In this paper, the possibility of meeting the growing electrical energy demands of the city of Ibadan (one of the Nigeria cosmopolitan city) using the rooftop solar PV systems is investigated with the aim of determining the available rooftop for possible PV deployment. First, the optimal tilt angle as well as solar irradiation on tilted surfaces are determined for the city, Thereafter, the available roof area for possible solar PV- rooftops placement are analysed using reduction factor technique with the aid of ArcGIS, Google earth Imagery and population sampling techniques. Some of the key results reveal that the total roof area for the city of Ibadan is about 49.54 sq km while the available roof area for rooftop PV deployment is about 7.54 sq km with a maximum installation capacity of 1734.8 MWp, at an optimum fixed tilt of 11°. This could generate PV electricity of about 6.67 TW h per annum. This paper is important as it could serve as first-hand scientific information for government agencies, NGOs, investors, researchers and policy makers at maximizing the potential of solar PV rooftop potentials in Nigeria.

Computation of optimum parameters to achieve the intrusion of mandibular central incisor and mandibular canine for deep bite treatment

Deep bite is a condition in which the maxillary and mandibular arch of teeth overlap with each other. Mandibular central incisor and mandibular canine are extruded significantly in this case. Hence, they need to intrude apically. The segmented arch technique is more effective than any other method for the correction of deep bite. However, there is no significant research to use a segmented arch technique in lingual orthodontics. Hence, the aim of the present research study is to specify accurate tilt (toe) angles in lingual orthodontics (LiO) required for intrusion of the mandibular central incisor and mandibular canine tooth for different positions from respective occlusal plane and to state comparative assessment of required tilt angles for both the teeth. For this purpose, single intrusive force was considered to act from top surface of a lingual bracket of the mandibular tooth. The position of application of intrusive force was considered from two factors, i.e. horizontal distance of bracket top surface from tooth surface and vertical distance of bracket top surface from an occlusal plane. In the present study, four different values of vertical distance of bracket top surface from an occlusal plane were considered. Thus, four different positions of application of intrusive force were considered for both the teeth (mandibular central incisor and mandibular canine). Required (optimum) tilt angles were computed mathematically for each tooth to pass the intrusive force vector through Cres. It is then verified with finite element analysis of CAD models of tooth assemblies. For the mandibular central incisor, the tilt angle was found to be 0° for vertical distance of 3 mm from an occlusal plane (OP). While, for mandibular canine, the tilt angle was found to be 0° for vertical distance of 2 mm from an occlusal plane (OP). Hence, these positions of point of application of intrusive force can be considered as better positions than others clinically.

Energetic and exergetic analysis of a sloped solar still integrated with a separated heat storage system incorporating phase change material

A single slope solar still coupled with a separated heat storage system consisting of a double glazing solar collector provided with latent heat storage material(PCM) is investigated in this paper. This system is moulded for working autonomously and continuously throughout the day. A transient model is developed for assessing the performances of this device under summer climatic conditions of the Algerian Sahara. In this model, the fraction of molten PCM was assessed at each time step, which allowed inspecting the evolution of PCM material during all the time of computations.The results indicate that the additional heat storage system supplied heat to the still for 20 h continuously during the daytime. Accordingly, it is found that the increase rates of daily and nocturnal yields were respectively 63% and 635% (an increase of more than six times) compared to the conventional system. Furthermore, it is exhibited that the useful energy is strongly influenced by the increase of PCM mass, so this parameter must be lowered as possible. Also, it is shown that in the summer season; there is an optimum tilt angle of 15° Meanwhile, it is demonstrated that a great part of the irreversibility generated in the system is caused by the solar radiation and the PCM irreversibility represents only 7% of the total irreversibility. It is also revealed that the daily irreversibility decreases slightly with increasing the water mass and collector slope angle, but possesses an optimum at a PCM thickness of 6 cm.

Evaluation of optimum PV tilt angle with generated and predicted solar electric data using geospatial open source software in cloud environment

Evaluation of optimum PV tilt angle with generated and predicted solar electric data using geospatial open source software in cloud environment