Study on the effect of PV tilt angle on power generation

The power generation of a photovoltaic (PV) system is significantly influenced by the tilt angle of the module. The system achieves the highest power efficiency when operated at the optimal tilt angle, which is typically considered in the design of system installation. In this study, the optimal tilt angle of photovoltaic (PV) modules is determined by using PVsyst software and analyzed through shadow simulation under specific boundary conditions. The study examines the power generation of photovoltaic (PV) panels at various inclination angles and illustrates the impact of inclination angle on PV panel power generation by using project-specific data. The study results indicate that the secondary optimization of the tilt angle by PVsyst, in conjunction with the geographic factors of a specific region in Hainan, reveals that the optimal installation tilt angle for maximum power generation benefit is 9°. This finding aligns with the best power generation and benefits from the actual installation, which is at 10° (adjacent to 9°). The conclusions drawn from the exploration emphasize the essential nature of EPC optimization for future projects, as it can serve as a valuable reference for the design of photovoltaic power generation systems.


Introduction
Solar energy represents an essentially inexhaustible source of energy.As a result of the rising energy demand and the gradual exhaustion of traditional energy sources, solar energy is gaining popularity as a significant renewable energy source.The potential radiation collected by photovoltaic (PV) panels is primarily affected by their orientation in relation to the horizon (azimuth and tilt angle) and local climatic conditions.This paper integrates real engineering projects and utilizes the industry-recognized photovoltaic design software PVsyst for data simulation demonstration.It provides a comprehensive analysis of the study results.
Stanciu et al. [1] performed a theoretical investigation into the most suitable tilt angle for solar collectors in various geographical locations and at different times of the year.They also put forward empirical formulas for determining the optimal tilt angle by using three distinct irradiation transposition models.In [2,3,4] , models that are relevant to the contexts of Egypt, Iran and Spanish regions were examined.Numerous scholars, both domestic and international, have compiled empirical formulas for determining the optimal inclination in various regions as a means of estimating inclination in the absence of meteorological data.Bari et al. [5] compiled various empirical formulas for optimal inclination.In the present era, technological advancements have made it feasible to utilize the industry-standard PVsyst 7.2 software for simulating and determining the optimal inclination angle for PV modules.Under identical boundary conditions, this study combines simulation and empirical data to analyze the influence of tilt angle on power generation.The aim is to identify correlations IOP Publishing doi:10.1088/1742-6596/2771/1/012027 2 between the data, providing a basis and direction for optimizing future EPC projects.When considering photovoltaic modules, it is important to note that the amount of irradiation received on the surface of the module varies with the solar incidence angle, even when the radiation input remains constant.Specifically, a larger angle of incidence (i.e., the angle between the incoming sunlight and the normal to the photovoltaic array) results in a reduced amount of solar radiation received perpendicular to the sun.Therefore, adjustments to the tilt angle of the module can impact the angle of incidence of the sun and subsequently affect the amount of radiation received.A theoretical calculation is necessary to determine the optimal inclination angle for maximizing solar radiation received throughout the year.This optimal inclination angle is crucial for maximizing solar energy absorption.
This paper proposes the establishment of a simulation involving 11 sets of inclination angles to compare theoretical simulation data with empirical data.The aim is to investigate the optimal inclination angle of the module in the region.The project requires maintaining consistency in all factors except for the inclination angle.The installation angle must align with the design angle without any deviation to accurately demonstrate variations in power generation across different module inclination angles.

Calculation process for tilt angle differentiation of PV power system
1.This study aims to investigate the impact of varying inclination angles on the power output of photovoltaic panels, drawing on the work of Tlijani [6] et al. who utilized the PVsyst software to determine the "optimal inclination" of a sloping surface at a specific location.
2. The yearly average values of surface light radiation for the "optimal inclination" and adjacent angles are documented.
3. The algorithm employed with constant boundary conditions compares the ultimate impact of each angle on power generation.The analysis of the project's current status, secondary optimization, and promotion is conducted.
The calculation scheme for differentiating the tilt angle of the PV power generation system can be intuitively understood from Figure 1.To collect and record the average annual radiation value for each tilt angle and its corresponding light harvesting surface, and then calculate the annual power generation for each tilt angle through integrated calculations.Based on the annual power generation data for each inclination angle, a secondary optimization is conducted and extended to the subsequent project development and research."Secondary optimization" is described in Section 2.4.

Boundary conditions
Taking a flatland PV power plant in Hainan Province as a case study, the main technical indicators are presented in Table 1.
Table 1.The primary technical indicators of a photovoltaic power station in Hainan.

Theoretical analysis of power generation at different inclination angles 2.3.1. Inclination selected analytical calculations.
According to the background of the project, the "PVsyst 7.2 software" is used to delineate the optimal tilt range values.The average annual solar radiation on the tilted surfaces at different angles is calculated from the obtained average solar radiation values, so as to maximize the power generation, and at the same time, the loss of solar energy resources reaches 0%.Taking Meteonorm 8.0 meteorological data as an example, according to PVsyst 7.2 software (Figure 2), the "optimal tilt angle data" can be got.And this is used to count the differences between the inclinations, which are selected as 0°, 5°, 10°, 12°, 13°,14°, 15°, 16°, 17°, 18°, and 20°.With the boundary conditions unchanged, only the variable of the tilt angle is changed, i.e., only the difference between string arrangement tilt angle and power generation is considered, and the total power generation obtained is analyzed for data comparison.
Annual electricity generation is calculated from photovoltaic systems.The installed capacity of 100 MW is taken as an example.The annual theoretical power generation is the amount of solar radiation energy converted into electrical energy by solar cells at photovoltaic conversion efficiency in a year, which can be referred to Yunus [7] , Daut and Irwanto [8] , and Khorasanizadeh [9] , et al.Combined with the present comprehensive power generation calculation method in China, the formula is as follows.
where: Q0 -annual theoretical power generation; E -Total annual solar radiant energy on the inclined plane; S -Total solar cell area; Ș -solar cell module efficiency.
theoretical hours of Internet access (h) = solar radiation (kWh/m 2 )/(1000 W/m 2 ) (2) The calculated statistics are presented in the form of Figure 3 below.From the data in Figure 3, it can be seen that there is not much difference in the average annual power generation and average annual equivalent utilization hours for the tilts adjacent to the optimum tilt angle (14°).

Quadratic optimization of inclination
The lower the latitude is, the longer the light hours are.In the practical operation of photovoltaic (PV) power plants, it is important not to overlook the power generation benefits derived from solar radiation outside the true solar time (9:00-15:00).The optimal tilt angle, in a narrow sense, refers specifically to the angle that produces the maximum power output during the true solar time, rather than the angle that maximizes power generation from the PV panels over the course of a year.The optimal tilt angle mentioned above is in close proximity to the angle for power generation, with minimal difference.However, when combined with the non-true sun hours of radiation resulting from the power generation gains, alternative angles may yield higher income at times.In this study, the angle that exhibits the highest annual integrated power generation gain is provisionally referred to as the optimal economic tilt angle.When the front and rear array spacing is determined, the PV module can be installed with a reduced tilt angle.This reduces morning and evening shadow shading loss, increases the effective radiation received by the tilted surface of the module throughout the day, and ultimately improves the system's power generation.This paper utilizes this approach to investigate the most advantageous economic tilt angle.
IOP Publishing doi:10.1088/1742-6596/2771/1/0120275 When the front and rear array spacing is determined, it is possible to reduce the PV module installation tilt angle.This reduction can minimize morning and evening shadow shading loss, leading to an increase in the effective radiation received by the tilted surface of the module throughout the day.Consequently, this improvement enhances the system's power generation.This paper relies on this to explore the optimal economic tilt angle.
In order to enhance the installed capacity of the photovoltaic (PV) system and minimize operational expenses, the front and rear array spacing is maintained at 6.5 m (established as a boundary condition), and the approach of decreasing the installation angle of PV modules is employed to refine the design of the PV square array tilt angle.This report employs the industry-standard software PVsyst to conduct shadow modeling simulations of PV arrays and to acquire effective irradiance data of tilted surfaces at various inclination angles for comparison, as depicted in Figure 4 below.This figure shows the "Angle of installation of lighting surface -Angle curve of annual comprehensive power generation" simulated by PYsyst software.Upon analysis of the graph, it is evident that the photovoltaic (PV) array produces the highest integrated power over the course of the year when the tilt angle of the light-harvesting surface is 9°.This finding contrasts with the previously identified optimal tilt angle.(The red dot represents 9° and the blue dot represents 14°.There is a 0.4% increase in the annual combined generation at 9° compared to the annual combined generation at 14°.) When the PV array spacing is kept constant at 6.5 m, reducing the PV square array tilt angle, the near-shadow shading loss is gradually reduced, and the integrated power generation of PV arrays throughout the year is gradually increased and reaches its peak at 9° tilt angle, and then starts to gradually decrease.
In summary, selecting a tilt angle of 9° for the lighting surface results in the highest effective irradiation value throughout the year.Therefore, adjusting the tilt angle of the PV arrays can increase comprehensive power generation compared to that achieved with the optimal tilt angle.
In this paper, PVsyst software simulates the PV module PV power plant, in the case of fixed bracket operation mode and keeping the front and rear row spacing of the bracket unchanged, the module uses different mounting tilt angles when the solar radiation is received by the light surface gain and PV power plant annual power generation, and the following conclusions are obtained.
1.When the module mounting inclination changes gradually by within 10°-20°, the change in average annual power generation is not significant at this time.
2. If on a fixed plot of land, the optimum economic tilt mounting arrangement is selected when there are no further boundary condition constraints.This move will maximize the benefit of the PV system for power generation.
3. Three different inclination angles of 5°, 10°, and 14° are set up in the validation area of the project for reference and comparison.The results show that the 10° (adjacent to the 9° obtained from the PVsyst shadow simulation) tilt angle is the best angle for the project, which is 1.4% higher than the maximum radiation tilt angle of 14° in terms of power generation hours, and the conclusions obtained are basically corresponding to the data in this simulation.

Conclusions
The optimal tilt angle determined through simulation by using the PVsyst system holds significant reference value for economic benefits.This paper utilizes data simulation and empirical data to offer practical guidance for future EPC projects.The study aims to provide a reference for the design of PV power generation systems and subsequent projects, with the goal of achieving higher power generation revenues in limited land resources.The findings are expected to offer valuable insights for researchers and the solar industry, facilitating the installation of highly efficient and cost-effective solar systems in various locations worldwide by determining the optimal tilt angle for each location.This study will

Figure 1 .
Figure 1.Flowchart of PV power system tilt angle differentiation.

Figure 2 .
Figure 2. Optimal inclination of the component.

Figure 3 .
Figure 3. Annual utilization hours corresponding to adjacent angles.

Figure 4 .
Figure 4. Comparative analysis of integrated power generation at various inclination angles.

Figure 5 .
Figure 5. Hourly power generation and Plane of Array Irradiance.