Tilt Orientation Research Articles

Evaluation index system for photovoltaic systems statistical characteristics under hazy weather conditions in central China

This study investigates different methods of determining the optimum tilt angle (OTA) for photovoltaic (PV) systems to maximise energy yield, and provides an evaluation index system for the static and dynamic performance of PV systems under hazy weather conditions, in view of the nature of solar energy resource and PV energy yield. Due to the fact that the data of total solar radiation on inclined surface in Wuhan is not available and PV power generation is non-linear process, an experimental off-grid PV system with various tilt angles and orientations is established which is located in Hubei Meteorological Administration in Wuhan. The experimental system is then used to analyse the accuracy of five in-plane solar radiation models and the relationship between the model predicted errors and meteorological environmental factors, explore the calculated and measured OTA of PV modules and evaluate the performance of PV system with different tilt angles and orientations based on static and dynamic indexes in real atmosphere condition. Finally, the influence of dust on PV energy production has been reported. After cleaning, the energy yield of PV models can increase by 10-20%.

Spatiotopic updating of visual feature information.

Saccades shift the retina with high-speed motion. In order to compensate for the sudden displacement, the visuomotor system needs to combine saccade-related information and visual metrics. Many neurons in oculomotor but also in visual areas shift their receptive field shortly before the execution of a saccade (Duhamel, Colby, & Goldberg, 1992; Nakamura & Colby, 2002). These shifts supposedly enable the binding of information from before and after the saccade. It is a matter of current debate whether these shifts are merely location based (i.e., involve remapping of abstract spatial coordinates) or also comprise information about visual features. We have recently presented fMRI evidence for a feature-based remapping mechanism in visual areas V3, V4, and VO (Zimmermann, Weidner, Abdollahi, & Fink, 2016). In particular, we found fMRI adaptation in cortical regions representing a stimulus' retinotopic as well as its spatiotopic position. Here, we asked whether spatiotopic adaptation exists independently from retinotopic adaptation and which type of information is behaviorally more relevant after saccade execution. We first adapted at the saccade target location only and found a spatiotopic tilt aftereffect. Then, we simultaneously adapted both the fixation and the saccade target location but with opposite tilt orientations. As a result, adaptation from the fixation location was carried retinotopically to the saccade target position. The opposite tilt orientation at the retinotopic location altered the effects induced by spatiotopic adaptation. More precisely, it cancelled out spatiotopic adaptation at the saccade target location. We conclude that retinotopic and spatiotopic visual adaptation are independent effects.

Optimal Tilt Angle and Orientation of Photovoltaic Modules Using HS Algorithm in Different Climates of China

Solar energy technologies play an important role in shaping a sustainable energy future, and generating clean, renewable, and widely distributed energy sources. This paper determines the optimum tilt angle and optimum azimuth angle of photovoltaic (PV) panels, employing the harmony search (HS) meta-heuristic algorithm. In this study, the ergodic method is first conducted to obtain the optimum tilt angle and the optimum azimuth angle in several cities of China based on the model of Julian dating. Next, the HS algorithm is applied to search for the optimum solution. The purpose of this research is to maximize the extraterrestrial radiation on the collector surface for a specific period. The sun’s position is predicted by the proposed model at different times, and then solar radiation is obtained on various inclined planes with different orientations in each city. The performance of the HS method is compared with that of the ergodic method and other optimization algorithms. The results demonstrate that the tilt angle should be changed once a month, and the best orientation is usually due south in the selected cities. In addition, the HS algorithm is a practical and reliable alternative for estimating the optimum tilt angle and optimum azimuth angle of PV panels.

Techno-economic analysis of photovoltaic battery system configuration and location☆

The techno-economic analysis investigates first the impact of tilt angle and orientation on the production profile of a rooftop solar generator and the related performance of a photovoltaic battery storage system for single family houses at a specific location in Germany. Then, a technical comparison to a different location in Almeria in Spain is performed.The calculations are model-based and take into consideration the consumer load profile, technical and economic photovoltaic battery storage system parameters as well as the framework of regulations for the case of Germany. The parameters “share of self-consumption”, “degree of autarky”, and “economic efficiency in terms of levelized cost of electricity” make up the focus of the modelling results. It is concluded that self-consumption and degree of autarky are strongly and inversely related. In terms of system design, a trade-off has to be made between aiming for high self-consumption and a high degree of autarky.Key findings from the modelling results reveal that in Lindenberg in Germany, a south orientation gives the highest degree of autarky and the lowest levelized cost of electricity, but with the lowest share of self-consumption as well. For rooftops oriented towards east/west, an interesting possibility could be to split the total installed capacity (equally) between the two orientations. This makes it possible to benefit from the high self-consumption of the east orientation and the high degree of autarky of the west orientation. In general, it has to be considered that the optimum orientation strongly depends on the consumer load profile. The technical analysis shows that changing the location to Almeria increases degree of autarky and decreases share of self-consumption for south orientation with different magnitude that depends on the load profile. Finally, the results show opposite impacts that depend on orientation and location when switching from a tilt angle of 30° to 45°. For a south orientation in Almeria and Lindenberg, the degree of autarky is increased when approaching the optimum tilt angle, while for west and east orientations in Lindenberg self-consumption increases.

Annual Optimum Tilt Angle Prediction of Solar Collector using PSO Estimator

The amount of solar flux falls on solar collector depends on tilt angle and orientation of collector from the surface. By efficiently regulating the tilt and orientation of solar collector unnecessary loss in potential power can be minimized. In general, for north hemisphere, south facing of the collector is considered as optimum orientation. There are several metrological and geographical factors which affect the optimum tilt angle. In this paper, the PSO estimator has been proposed in order to find optimum tilt angle on annual basis. The results of PSO estimators are compared with ANN estimator and satellite (RETScreen software) data. To evaluate the performance of proposed model MBE, RMSE, Error range, percentage annual error as well as direct method of statistical study have been carried out. During annual tilt angle prediction the annual percentage errors of proposed method and RETScreensoftware data are 0.03% and 7.03% respectively with respect to ANN results. Finally, the average percentage error indicates that the proposed estimator gives better prediction as compared to satellite based results for collecting maximum solar flux at surface of solar collector.

Evaluation of potential benefits of solar photovoltaic shadings in Hong Kong

Solar photovoltaic (PV) modules can not only generate electricity but also act as external shading devices of buildings. Solar PV shadings can effectively reduce the solar heat gain through windows, but might have a negative impact on the indoor daylight performance. Therefore, it is worth investigating the optimum design of solar PV shadings since the thermal, daylighting and power generation performance are closely integrated. In this paper, a numerical simulation model was utilized on the basis of EnergyPlus to investigate the energy saving potential of solar PV shadings with various tilt angles and orientations in Hong Kong. The results indicate that the optimum installation position for solar PV shadings is south facade with 30° tilt angle in order to maximize the electricity generation. However, considering the electricity savings from air-conditioning system and the increased electricity consumption for artificial lighting, it is recommended that solar PV shadings should be installed on a south facade with 20° tilt angle. Furthermore, the annual overall electricity benefits of solar PV shadings were compared with the widely used interior blinds. The results show that the well-designed solar PV shadings can achieve much more annual overall electricity benefits than interior blinds.

Cut-off deviation for CSL boundaries in recrystallized face-centered cubic materials

Brandon’s criterion is frequently used to quantify distribution of coincident site lattice (CSL) boundaries in studies related to grain boundary character distribution. This criterion is based on theoretical considerations and is meant to define a range within which special boundaries may exist. Experiments have repeatedly shown that this range includes boundaries which do not show special properties. A broad aim of this study is to explore if there exists a cut-off in deviation which includes only boundaries with special properties. While most other criteria in literature are based on theoretical dependence of secondary dislocation spacing, in this work we find the cut-off deviation through experimental data of recrystallised microstructures from in situ as well as ex-situ heating experiments. Deviation from structure was considered in terms of both, deviation of misorientation axis-angle as well as deviation of the boundary plane from the symmetric tilt orientation. Our results indicate that the deviation in terms of misorientation angle is more important than boundary plane deviation. We also show that the limiting deviation for various orders of twin boundaries (Σ3n) in a recrystallized microstructure is a constant and approximately 1° which is significantly lower than that defined by Brandon’s criterion. We show that this constant cut-off deviation for various Σ3n CSL boundaries can also be obtained by assuming that the secondary dislocations are spaced proportional to displacement shift complete lattice vector. Similar analysis was also carried out for non-Σ3n boundaries but due to limited statistics, no cut-off value could be deduced for these boundaries.

Tilt Angle and Orientation Impact on the Techno-economic Performance of Photovoltaic Battery Systems

The techno-economic analysis investigates the impact of tilt angle and orientation on the production profile of a rooftop solar generator and the related performance of a photovoltaic battery storage system for single family houses at a specific location in Germany. The calculations are model-based and take into consideration the consumer load profile, technical and economic photovoltaic battery storage system parameters as well as the framework of regulations. The parameters “share of self-consumption”, “degree of autarky”, and “economic efficiency in terms of levelized cost of electricity” make up the focus of the modelling results. It is concluded that self-consumption and degree of autarky are strongly and inversely related. In terms of system design, a trade-off has to be made between aiming for high self-consumption and a high degree of autarky. Key findings from the modelling results reveal that a south orientation gives the highest degree of autarky and the lowest levelized cost of electricity, but with the lowest share of self-consumption as well. For rooftops oriented towards east/west, an interesting possibility could be to split the total installed capacity (equally) between the two orientations. This makes it possible to benefit from the high self-consumption of the east orientation and the high degree of autarky of the west orientation. In general it has to be considered that the optimum orientation strongly depends on the consumer load profile. Finally, the results show two opposite impacts that depend on orientation when switching from a tilt angle of 30° to 45°. For a south orientation, the degree of autarky is increased, while for west and east orientations, self-consumption increases.

Abstract No. 564 - Comparison of Celect and Denali filters: Tilt angles and tilt orientations

Abstract No. 564 - Comparison of Celect and Denali filters: Tilt angles and tilt orientations

Variable Crystal Orientation of Poly(ethylene oxide) Confined within the Tubular Space Templated by Anodic Aluminum Oxide Nanochannels

The use of nanoscale templates to confine the crystallization process is an effective approach for creating large-scale crystal orientation. Here we incorporated poly(ethylene oxide) (PEO) into anodic aluminum oxide (AAO) nanochannels by a solution infiltration process to generate PEO nanotubes confined in the channels. The preferred crystal orientation of the PEO crystallites developed in the tubular space was then studied as a function of crystallization temperature (Tc), PEO molecular weight (MPEO), and AAO channel diameter (DAAO = 23 and 89 nm). Two distinct types of crystal orientation, i.e., perpendicular and tilt orientation with the (120) plane aligning along and tilting 45° away from the channel axis, respectively, were identified. Crystallization in the nanotubes templated by the AAO with DAAO of 23 nm led predominantly to perpendicularly oriented crystallites except for the high molecular weight PEO (MPEO = 95 000 g/mol), where a significant fraction of the crystallites showed tilt orientation....

A Review on Optimal Inclination Angles for Solar Arrays

The knowledge of solar radiation falling on horizontal surface is the fundamental requirement for installing and monitoring the solar technologies. Due to variable nature of sun radiation, the power production of solar photovoltaic is fluctuating as compare to conventional power plant that’s why the cost of power is increase. During the many decades, in order to estimate the horizontal components of solar radiation on hourly, daily and monthly mean basis have been estimated by different empirical models. There is one possible solution to improve the power production cost by changing the tilt angle and orientation angle on the basis of different factors such as time, season and location. To capture the maximum solar radiation inclination angle play an important role. The purpose of this study is to provide a review of different diffuse models proposed in past and provides the optimal tilt angle for different locations around the world on the basis of monthly, seasonally, bi-annually and yearly. This review would be beneficial for the further research in solar energy in term of, to identify the optimal tilt angle and collection of radiation for different location in the globe. Additionally, to get the proper accuracy and reliability of orientation angle and tilt angle to get the strong correlation with solar radiation for different time periods such as monthly, seasonally, half yearly and yearly at desired location.

Impact of Solar Panel Orientation on Large Scale Rooftop Solar Photovoltaic Scenario for Mumbai

Abstract Application of solar photovoltaic systems at a large scale is becoming increasingly interesting for researchers, policymakers and investors. Singh and Banerjee (2015) [1] have presented a methodology for estimation of the rooftop solar photovoltaic potential of a city. The methodology has been applied and illustrated for the Indian city of Mumbai (18.980N, 72.830E). In this paper, different orientations of the solar panels to be used for the Mumbai rooftop solar photovoltaic scenario have been analyzed and compared in terms of their impact on the generation from the scenario. The three possible orientations studied and compared in this study are – fixed tilt orientation, two-point system orientation, and horizontal N-S axis E-W tracking. The results show that for the fixed tilt orientation, the best tilt angle for year-round optimal performance is same as the latitude of the place, i.e. 190. However, optimization of seasonal output would warrant another tilt angle. Further, it has been found that, as compared to the fixed tilt at 190, the two-point system gives 2.21% higher annual plane-of-array insolation; and horizontal N-S axis E-W tracking gives 10.18% higher annual plane-of-array insolation. However, in terms of the annual generation from the large scale Mumbai rooftop scenario, the gain is only 1.97% with the two-point system, and 9.62% with the horizontal N-S axis E-W tracking, as compared to the fixed tilt (at 190) orientation. Incremental cost-benefit analysis for the excess capital expenditure on the tracking equipment has also been done. For this analysis, the Average Unit Cost of Power Supply for India has been taken into account, which is found to have a CAGR of 8.57% over the last decade; discount rate has been estimated as per the Renewable Energy Tariff Regulations passed by the Central Electricity Regulatory Commission (CERC), and has been found to be 10.76%. The ensuing analysis gives a discounted payback period of around 13 years for the excess capital expenditure due to the tracking equipment costs.

Relationship of sagittal alignment and acetabular orientations as measured in upright position in asymptomatic adults

While sagittal alignment is known to significantly influence hip prosthesis positioning after total hip arthroplasty [1] , the effect of sagittal alignment on acetabular orientation has not been previously studied in asymptomatic adult subjects. The aim was to elucidate the relationships between sagittal alignment and acetabular orientation using three-dimensional (3D) reconstruction of the hip in standing position. One hundred and seventy four hips of 87 asymptomatic adult subjects with no prior orthopedic treatment (age = 21.5 ± 2.2 years; 47 males and 40 females) that had undergone full body biplanar X rays, in standing position, with 3D reconstruction of the spine, pelvis and femurs were reviewed. Classic sagittal spino-pelvic alignment parameters were obtained as well as the following hip-specific ones: Lewinek vertical angle, acetabular anteversion (orientation of the acetabulum in the axial plane), abduction (orientation of the acetabulum in the frontal plane) and tilt (orientation of the acetabulum in the sagittal plane), percentage of femoral head coverage by the acetabulum. Pearson correlations were computed between acetabular parameters and sagittal spino-pelvic parameters. Stepwise multiple linear regressions were then used in order to elucidate the most determining sagittal alignment parameters for acetabular orientation. While the percentage of femoral head coverage was independent of all the sagittal alignment parameters, significant correlations (p [2] .

An Optimized Model for Solar Thermal Collectors Based on Concept of Effective Heat Collection

The performance of solar collector highly relies on its tilt angle with respect to horizontal plane and orientation (surface azimuth angle) of the collector. The effective heat collection concept was proposed and an optimized mathematical model was further developed to determine the optimum tilt angle and orientation for the solar collector. The developed model was applied in a case study of the Lhasa district, in comparison with the results obtained in accordance with conventional optimization results. The research results showed that, there is about 5 deviation between the optimum results obtained according to effective heat collecting capacity and the optimum results obtained according to maximum total solar radiation falling on the solar collector.

Effect of Tilt and Azimuth Angle on the Performance of PV Rooftop System

This paper focuses on to evaluate technical performance of PV roof top system. This system totally consists of 168 polycrystalline modules in which 14 are connected in series and 12 are connected in parallel. The total capacity of the system is 50 kWp, in which each module has the rated power capacity of 305 Watt. This system is connected to three 20kW inverters and which intern is connected to grid. Tilt angle and orientation is obtained by MATLAB 7.10 and PVsyst software for each 150 change in tilt angle, the variation in solar irradiance absorbed by the PV modules, variation in energy produced by the modules and the variation in the final yield are observed. MATLAB software is also used to find the curve fitting by using surface fitting tool. The result showed that at 150 tilt and 450 azimuth angles, the maximum yield and effective energy were obtained as 4.65 h/day and 1394 kWh/kWp/year respectively.

IMU-바로미터 기반의 수직변위 추정용 이단계 칼만/상보 필터

Estimation of vertical position is critical in applications of sports science and fall detection and also controls of unmanned aerial vehicles and motor boats. Due to low accuracy of GPS(global positioning system) in the vertical direction, the integration of IMU(inertial measurement unit) with the GPS is not suitable for the vertical position estimation. This paper investigates an IMU-barometer integration for estimation of vertical position (as well as vertical velocity). In particular, a new two-step Kalman/complementary filter is proposed for accurate and efficient estimation using 6-axis IMU and barometer signals. The two-step filter is composed of (i) a Kalman filter that estimates vertical acceleration via tilt orientation of the sensor using the IMU signals and (ii) a complementary filter that estimates vertical position using the barometer signal and the vertical acceleration from the first step. The estimation performance was evaluated against a reference optical motion capture system. In the experimental results, the averaged estimation error of the proposed method was 19.7 cm while that of the raw barometer signal was 43.4 cm.

Solar Receivers Optimum Tilt Angle at Southern Hemisphere

One of the important parameters that affects the performance of a solar collector is its tilt angle with the horizon. This is because the variation of tilt angle changes the amount of solar radiation reaching the collector surface. Meanwhile, is the rule of thumb, which says that solar collector should be orientated towards the Equator with a tilt equal to latitude, valid for high latitudes region? Thus, it is required to determine the optimum tilt for Equator facing collectors. In addition, the question may rise: how much adjustments of Equator facing solar collector tilt angle is reasonable to do during a year? A mathematical model was used for estimating the solar radiation on a tilted surface, and to determine the optimum tilt angle and orientation (surface azimuth angle) for the solar collector at any latitude. This model was applied for determining optimum tilt angle in the high latitudes zone in the Southern Hemisphere, on a daily basis, as well as for a specific period. The optimum angle was computed by searching for the values for which the radiation on the collector surface is a maximum for a particular day or a specific period. The results reveal that changing the tilt angle 12 times in a year (i.e. using the monthly optimum tilt angle) maintains approximately the total amount of solar radiation near the maximum value that is found by changing the tilt angle daily to its optimum value. This achieves a yearly gain in solar radiation up to 1.8 times of the case of a horizontal surface while the daily gain reaches 60 times approximately. Moreover, general formulas are proposed for predicting daily optimum tilt angle and optimum tilt angle over any number of days.

East to west – The optimal tilt angle and orientation of photovoltaic panels from an electricity system perspective

The integration of photovoltaic as a fluctuating renewable energy source has raised concerns about additional costs for the electricity system due to the variable nature of power output leading to more frequent and steeper ramping of conventional power plants and the need for backup capacity. One way to reduce those costs can be the variation of installation angles of PV panels at different locations to smoothen out the total production from PV in the whole system. To a certain extent steeper tilt angles can shift the production from summer months to winter months and the variation of the azimuth from east to west can partly shift production during the day increasing the production in morning or afternoon hours. However, for fixed mounted PV panels, there is one angle combination that maximizes the total output of the PV panel throughout the year and each deviation from this angle combination results in losses of total output. This paper evaluates the trade-off between annual energy losses and possible electricity generation cost reductions through adapting PV installation angles for the current electricity system and for potentially higher PV penetration levels in the future. A theoretical explanation why the annual maximum output of a PV system is not always the optimal solution from a system perspective is presented. To assess the effects of deviations from output maximizing angles at present, the wholesale market value of PV for various tilt angles and orientations in 23 regions of Austria and Germany using historic data on solar radiation and hourly electricity prices is calculated. For the analysis of future system states with potentially high shares of PV in the market, a linear optimization model representing the German and Austrian electricity wholesale market is applied. Furthermore the article provides additional insights on the market value of PV and CO2 emission reduction potential at high PV penetration levels from the model.Both, the historic analyses and the model results for Austria and Germany suggest that at present PV penetration levels, the angle combination that maximizes the output of a PV system also provides the highest spot market value and consequently minimal total system costs. For higher shares of PV in the system the model suggests deviations from those angle combinations to be optimal. For additional PV capacity of up to 40GW (72GW in total) a slight shift to easterly orientated PV modules is observed. For very high penetration levels of more than additional 100GW optimal deviation angles deviate strongly from the output maximizing angles and the model shows optimal angles to be up to 20° steeper and orientations from east to west. However, the impact on total electricity generation costs is very low even for extremely high shares of PV in the system (<1% change in total costs). It is also found that despite of optimized installation angles, the average market value of electricity production from PV drops significantly from 41€/MWh at the base year 2012 to below 24€/MWh for additional 40GW which has strong implications for the competitiveness of PV in the future. Marginal CO2 emission reductions however decline slower than the market values as PV cuts into production from coal power plants.

Measuring in situ krill tilt orientation by stereo photogrammetry: examples for Euphausia superba and Meganyctiphanes norvegica

Abstract The natural body orientation adopted by krill is a crucial parameter for understanding and estimating the acoustic backscattering from these animals. Published data are scarce and are usually acquired with single camera systems that provide suboptimal control over the measurement accuracy. Here, we describe a stereo photo camera application for accurate krill measurements in situ, based on several Euphausia superba and Meganyctiphanes norvegica datasets. Body tilt orientation, body length, and school volume density from scattered and schooling krill are presented. Some challenges to the practical implementation of the method are discussed, including practical limits on krill body yaw angles for obtaining useful measurement accuracy and how to account accurately for the true vertical. Calibration and measurement accuracy is discussed together with a practical definition of krill body orientation. Krill sizes determined from stereo images are compared with those measured from trawl samples. The krill body tilt measurements yielded mean estimates of positive (head-up) or negative tilt of 9–17° with rather large spread for scattered aggregations of M. norvegica (SD = 30–37°) and about half of that for polarized schools of E. superba (SD = 14–17°). The measured krill body orientation distributions were also used to calculate krill acoustic target strength as predicted by the stochastic distorted wave Born approximation (SDWBA) model.

REVISITING THE ISN FLOW PARAMETERS, USING A VARIABLEIBEXPOINTING STRATEGY

The Interstellar Boundary Explorer (IBEX) has observed the interstellar neutral (ISN) gas flow over the past 6 yr during winter/spring when the Earth's motion opposes the ISN flow. Since IBEX observes the interstellar atom trajectories near their perihelion, we can use an analytical model based upon orbital mechanics to determine the interstellar parameters. Interstellar flow latitude, velocity, and temperature are coupled to the flow longitude and are restricted by the IBEX observations to a narrow tube in this parameter space. In our original analysis we found that pointing the spacecraft spin axis slightly out of the ecliptic plane significantly influences the ISN flow vector determination. Introducing the spacecraft spin axis tilt into the analytical model has shown that IBEX observations with various spin axis tilt orientations can substantially reduce the range of acceptable solutions to the ISN flow parameters as a function of flow longitude. The IBEX operations team pointed the IBEX spin axis almost exactly within the ecliptic plane during the 2012-2014 seasons, and about 5° below the ecliptic for half of the 2014 season. In its current implementation the analytical model describes the ISN flow most precisely for the spin axis orientation exactly in the ecliptic. This analysis refines the derived ISN flow parameters with a possible reconciliation between velocity vectors found with IBEX and Ulysses, resulting in a flow longitude lambda∞ = 74.°5 ± 1.°7 and latitude beta∞ = -5.°2 ± 0.°3, but at a substantially higher ISN temperature than previously reported.