
==== Front
Sci Rep
Sci Rep
Scientific Reports
2045-2322
Nature Publishing Group UK London

39223170
70015
10.1038/s41598-024-70015-3
Article
Performance analysis of floating bifacial stand-alone photovoltaic module in tropical freshwater systems of Southern Asia: an experimental study
Pandian Ganesan Rathinavel 1
Balachandran Gurukarthik Babu mspsbguru@gmail.com

1
David Prince Winston 1
K Sangeetha sangeethak@kdu.edu.et

2
1 grid.252262.3 0000 0001 0613 6919 Department of Electrical and Electronics Engineering, Kamaraj College of Engineering and Technology, Kallikudi, Tamil Nadu 625701 India
2 https://ror.org/00r6xxj20 Department of CSE, Kebri Dehar University, Kebri Dehar, Somali Ethiopia
2 9 2024
2 9 2024
2024
14 2035215 3 2024
12 8 2024
© The Author(s) 2024
2024
https://creativecommons.org/licenses/by-nc-nd/4.0/ Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
The optimization of floating bifacial solar panels (FBS PV) in tropical freshwater systems is explored by employing response surface methodology (RSM) and central composite design (CCD). Previous studies have yet to explore the long-term durability, environmental impact, economic viability, and performance of FBS PV systems under various climatic conditions. This study addresses this gap by focusing on panel height, water depth, and tilt angle to improve performance. The quadratic model reveals significant non-linear relationships impacting FBS PV power generation with freshwater cooling. Our models demonstrate high explanatory power, with R-squared values of 0.9831 for output power and 0.9900 for Bi-Facial gain. Experimental validation using conventional white surface (CWS) and proposed freshwater surface (PFS) indicates notable improvements in power generation, achieving a 4.34 to 4.86% gain in bifacial efficiency across various irradiation levels. Under 950 W/m2 irradiation, freshwater cooling achieves a 3.19% higher bifacial gain compared to CWS cooling. Panel temperature analysis shows consistent reductions with freshwater cooling, ranging from 1.43 to 2.72 °C, enhancing overall efficiency and longevity. This research highlights the potential of freshwater cooling in optimizing bifacial solar systems, offering actionable insights for sustainable energy solutions in tropical regions.

Keywords

Bifacial solar panels
Response surface methodology (RSM)
Freshwater cooling
Quadratic model optimization
Bifacial gain
Solar panel temperature
Central composite design
Subject terms

Energy science and technology
Engineering
issue-copyright-statement© Springer Nature Limited 2024
==== Body
pmcIntroduction

The performance of bifacial solar cells has garnered significant attention due to their ability to capture sunlight from both sides, thereby increasing overall energy yield. Recent advancements in technology have further improved their efficiency and reliability, making them a promising solution for various applications in the renewable energy sector. The use of RSM has proven itself as a tool for revealing the sensitivity of design parameters and establishing correlations determining performance gains1. This optimization approach, as demonstrated in the field of solar air heaters2, highlights the versatility of in renewable energy research. In parallel, the integration of parabolic BFS panels with cooling systems brings innovative concepts andchallenges3, while the investigation of novel BFS photothermal and radiative cooling modules4 contributes to a holistic understanding of system dynamics. In the context of compound parabolic concentrators, experimental investigations shed light on the performance of flat receivers5. In addition, an in-depth investigation examines the effects of modifying the focal lengths of a compound parabolic concentrator6, which offers a different perspective on concentrating photovoltaic and thermal systems. Extending the discussion on sustainable freshwater production, a new design of wick-type solar stills7 is investigated for theoretical and experimental insights. Optimization of dihedral solar modules has been a key focus for researchers, particularly those in study8, who refined the angle and positioning of panels to maximize solar absorption and energy conversion efficiency. This involved a meticulous analysis of geometric configurations to ensure that the modules could capture the maximum amount of sunlight throughout the day, improving overall system performance. Similarly, the team in study9 investigated how variations in surface reflectivity (albedo) impact the performance of these dihedral solar modules. By understanding how different surface characteristics affect solar energy absorption, they provided crucial insights for optimizing panel placement in diverse environmental conditions. This research is essential for adapting solar technology to various geographical locations, enhancing its efficiency.

The integration of thermal and electrical energy generation in bimodal photovoltaic thermal systems was the focus of study10. The authors designed and validated these systems to improve overall efficiency and practical usability. By combining two forms of energy generation, they aimed to maximize the output from solar panels, making the technology more versatile and effective. In study11, a comparative analysis between monomodal and bimodal photovoltaic modules, especially in floating power plants, was conducted. This research sought to identify the most efficient and sustainable configurations for floating solar systems, contributing significantly to the development of sustainable energy solutions. The review in study12 comprehensively assessed bimodal photovoltaic technologies, highlighting the current status and future potential of these systems. This overview emphasized the necessity of an integrated research approach to advance solar energy technologies. Studies13 and14 explored the relative performance of different solar panel configurations, including tandem solar panels with MOS cells designed for harsh desert environments. These investigations aimed to expand the applicability of solar technology across diverse climatic conditions, ensuring that solar panels can perform optimally in various settings. The practical implications of floating PV technology were analyzed in study15, where real-world applications and performance metrics were examined. This study provided valuable data on the viability and efficiency of floating solar systems in different environments, highlighting their potential in real-world applications.

Critical aspects of solar panel lifecycle management and the impact of local microclimates on floating solar power plant efficiency were addressed in studies15 and16. These contributions are crucial for developing sustainable and long-lasting solar solutions, ensuring that solar technology can withstand and adapt to environmental changes over time. Study17 focused on innovative floating Schottky gate junction solar cells, aiming to enhance the efficiency and durability of solar cells used in floating applications. This research is vital for improving the robustness of solar technology in various conditions. The simulation of floating solar PV performance was the focus of study18, which provided predictive insights into the efficiency and effectiveness of these systems under various conditions. Such simulations are essential for understanding potential performance issues and optimizing system design. Finally, research19 explored the potential of floating solar PV systems to reduce water evaporation in water-stressed areas. This dual-purpose approach not only enhances solar energy generation but also conserves critical water resources, demonstrating the multifaceted benefits of floating solar technology. These collective studies offer diverse perspectives and practical solutions for optimizing the performance and sustainability of solar technologies, advancing the field significantly.

Liu et al.20 analyze the field performance of floating PV technologies in the tropics, emphasizing global tracking and the widespread geographical distribution and scale of BFS installations. Concurrently, Ref.21 investigates the impact of floating photovoltaic systems on temperature and water quality, crucial for understanding environmental effects. Innovations like floating bifacial photovoltaic systems22 and designs tailored for marine environments23 exemplify ongoing technological advancements in BFS. Additionally, Ref.24 introduces nature-inspired evolutionary algorithms, enhancing performance evaluations of floating solar modules through biomimetic design principles. Continued advancements are showcased through initiatives such as optimizing front diffusion profiles in bifacial interdigitated back-contact solar cells25 and evaluating n-type PERT BFS photovoltaic modules under varying albedo conditions26. These efforts highlight a commitment to improving solar efficiency and performance across different environmental contexts. Rooted in rigorous experimentation and analysis, these studies collectively set a benchmark for evaluating the potential of BFS technology. The evaluation of a novel BFS photothermic and radiative cooling module (27) serves as a pivotal benchmark in assessing the technological capabilities of floating solar systems. Furthermore, insights from28 on power loss rates in tropical regions provide critical background against which current research unfolds, particularly in understanding environmental and climatic impacts on BFS performance.

Mohr et al.29 explored the BICON system, a high concentration photovoltaic (PV) technology utilizing one-axis tracking and silicon concentrator cells to enhance energy output. Arnaoutakis et al.30 investigated improved up-conversion techniques for PV applications through the integration of concentrating optics, which significantly boosted photovoltaic efficiency. Lehr et al.31 analyzed the energy yield of bifacial textured perovskite/silicon tandem photovoltaic modules, demonstrating their enhanced performance. Arnaoutakis et al.32 developed single crystal monolithic upconverter solar cell device tandems with integrated optics, showcasing significant advancements in photovoltaic technology by effectively improving energy conversion efficiency through innovative optical integration techniques. Smith et al.33 performed an in-depth degradation analysis, demonstrating the model’s accuracy in predicting long-term durability of transparent backsheets used in bifacial photovoltaics. Additionally, Liang et al.34 reviewed the performance characterization and simulation of crystalline silicon bifacial photovoltaics, confirming the model’s reliability through extensive experimental and simulation data. These studies substantiate the two-diode model's effectiveness.

Research in the field of floating solar (BFS) technology has made significant strides in improving efficiency and sustainability. However, a critical research gap lies in comprehensive studies evaluating the long-term environmental impacts and economic feasibility of BFS installations across diverse geographical and climatic conditions. Further research is needed to optimize solar panel height, azimuth angle, water depth, and bifacial gain to maximize overall system efficiency and performance.

Our research integrates a global perspective on solar technology, emphasizing sensitivity analysis of design parameters and power gain correlations through response surface methodology (RSM). We aim to optimize bifacial solar panel height, azimuth angle, and water depth using Design Expert software, followed by an analysis of power output and bifacial gain relative to conventional surfaces, advancing sustainable energy solutions in floating solar (BFS) systems.

Methodology

The visual Fig. 1 representations showcase the flowchart detailing our investigative research. The methodology employed in this research involves several critical steps to optimize the performance of bifacial solar panels (BFS) on floating platforms. Initially, the problem was identified, focusing on inefficiencies in current BFS systems. Bifacial solar panels were installed on a floating platform, and their initial efficiency was measured to establish a baseline. The testing phase involved varying water depths (2, 6, and 10 cm), panel heights (25, 87.5, and 150 cm), and tilt angles (45, 90, and 135°). Data collected during these tests was analyzed using Response Surface Methodology (RSM) to understand the influence of multiple variables. This analysis guided the optimization of output power and bifacial gain. Experimental set up was done using both conventional white surface and proposed freshwater surface methods for comparison. Output power and bifacial gain were measured for both setups, with the data analyzed to draw conclusions. Finally, the findings were summarized, highlighting the implications and potential applications of the improved BFS systems.Figure 1 Flow diagram of experiment.

Site selection

For our investigation, we meticulously chose Kamaraj College of Engineering and Technology in Viruthunagar, situated at latitude 9.67 and longitude 77.96 (Fig. 2). An annual average temperature of 28 °C, with sunshine duration averaging 8 h per day. The region receives approximately 830 mm of annual precipitation, predominantly during the monsoon season. The annual average wind speed is around 4.5 m/s. These meteorological conditions are vital for understanding the environmental influences on the BFS panels and ensuring comprehensive and accurate experimental outcomes.Figure 2 Site location selected for experiment.

Figure 2: Map showing the location of Kamaraj College of Engineering & Technology (Autonomous), generated using Google Maps (accessed on 15.07.2024). URL: https://shorturl.at/2i3ff.

The weight of this solar panel is Approximately 21 kg. The panel dimensions are 200 cm (L) × 100 cm (W) × 4 cm (B). It was placed on the rooftop, hence the shadow effect and shadow factor could be mitigated. For optimal performance, the panel is positioned 90 degrees from south facing in a counterclockwise direction, meaning it lies flat and parallel with the surface. The available surface area is 250 cm (L) × 150 cm (W). By strategically opting for this location, our research endeavors to provide valuable insights for informed decision-making in future solar projects. The distinctive attributes of this site significantly contribute to a holistic comprehension of BFS panel behavior.

Uncertainty analysis

The uncertainty analysis for the experimental apparatus reveals key specifications in (Table 1). The analog ammeter, with a range of (0–10) A, maintains an accuracy of 0.1 A, resulting in a 1% uncertainty. The digital multimeter, covering (0–1000) V, boasts an accuracy of 20 V, with a 2% uncertainty. The Meco 936 solar power meter, measuring (0–3000) W/m2, carries a precision of 60 W/m2, leading to a 2% uncertainty. Similarly, the thermal imaging camera, operating within (−20–250) °C, demonstrates an accuracy of 5 °C, contributing to a 2% uncertainty. This detailed uncertainty analysis ensures reliability and precision in experimental measurements. Table 1 Instrument accuracy and range with standard uncertainty measurements.

S.No	Instrument	Accuracy	Range	Standard uncertainty	
1	Ammeter	 ± 1%	0–20 A (MC)	 ± 1%	
2	Pyranometer	 ± 1 W/m2	0–5000 W/m2	0.57 W/m2	
3	Thermal Imaging Camera	 ± 1%	Digital	 ± 2%	
4	Voltmeter	 ± 1%	0–100 V (MC)	 ± 1%	
5	Anemometer	 ± 2%	0 to 30 m/s	 ± 1%	

Construction of floating solar panels

This study uses a two-sided floating solar panel designed according to the specifications provided by the manufacturer. Figure 3 shows the equivalent Circuit of BFS PV module. These panels use double-sided solar cells that absorb sunlight from the front and back to increase efficiency. This design differs from conventional single-axis solar modules and offers distinct advantages. Dihedral photovoltaic modules are excellent not only in absorbing frontal sunlight, but also in harnessing light reflected from albedo surfaces. Albedo is influenced by environmental factors such as environmental conditions, panel height, tilt angle and distance between modules and plays an important role in the efficiency of floating solar power installations. The precise construction and integration of these double-sided solar panels is intended to maximize energy absorption and optimize performance in various environmental conditions.Figure 3 Equivalent circuit of BFS PV.

The experimental equipment comprises a Bifacial PV module with specifications: Voc = 46.8 V, Isc = 10.97 A, Vmp = 38.3 V, Imp = 9.42 A, Pmax = 395 W. The thermal imaging camera has a range of −20–250 °C, and the Meco 936 solar power meter measures from 0 to 3000 W/m2. These tools collectively provide a comprehensive and versatile platform for solar energy research and testing.

BFS panel fixation using optimization

The experiment conducted for this research leveraged RSM to optimize the performance of BFS panels with freshwater cooling shown in (Fig. 4). Utilizing a quadratic model within CCD, we systematically explored panel height, water depth, and tilt angle as crucial design parameters. The analysis, driven by low p-values, emphasized the statistical significance of these factors and their interactions. Quadratic terms, such as A2, B2, and C2, highlighted non-linear nuances, while high F-values reflected the substantial effects on responses. With R-squared values near 1, the models exhibited a strong ability to explain variability. This comprehensive analysis provides a robust foundation, enabling the precise optimization of BFS Power System with efficient cooling methodologies.Figure 4 Experimental setup.

Experimental set up and data collection

The data collection phase for the conventional white surface (painted with normal white paint) and the proposed fresh water surface (immersed in fresh water with a white paint surface), guided by insights from RSM results, and was conducted with meticulous precision to evaluate the performance of BFS panels under various conditions. Leveraging the optimized parameters derived from RSM, including Panel Height, Water Depth, and Tilt Angle, a systematic approach was adopted to gather empirical evidence. Specifically, experiments were conducted to compare the performance of BFS panels on a white surface, utilizing normal white paint, and under a fresh water cooling system shown in (Fig. 4). This comprehensive data collection involved monitoring key performance indicators such as output power and bi-facial gain. The objective was to discern the impact of different cooling methods on the efficiency of BFS panels, with a particular focus on real-world scenarios. Rigorous measurements and analyses were conducted to provide a robust dataset that could serve as a foundation for the subsequent stages of analysis and comparison. This data collection process not only adhered to the optimized parameters but also ensured a holistic understanding of the BFS panels’ behavior under diverse conditions, contributing valuable insights to the overarching research endeavor.

Analysis and comparison

The analysis and comparison phase constituted the culmination of the research endeavor, synthesizing the extensive data collected from both the white surface and fresh water experiments to draw meaningful conclusions about the performance of BFS panels. Applying statistical rigor, the gathered data was subjected to a comprehensive analysis, considering parameters such as Output Power and Bi-Facial Gain. Through a meticulous examination of the results under different conditions derived from the optimization, trends and patterns emerged, shedding light on the nuanced dynamics of BFS panels. The comparison between the panels on a white surface and those employing a fresh water cooling system offered valuable insights into the impact of cooling methods on overall efficiency. The study not only evaluated the immediate performance but also assessed long-term considerations, contributing to a holistic understanding of the BFS panel behavior. The findings provided a nuanced perspective on the influence of environmental factors on power generation, facilitating informed decision-making for the adoption of BFS technologies in practical applications. This analysis and comparison phase thus served as the cornerstone for the research, bridging theoretical insights with practical implications and advancing the discourse on optimizing BFS Power System.

Results and discussion

Influence of environmental background on FBS PV system

The experiment focused on various environmental parameters, including solar irradiation, ambient temperature, PV module surface and backside temperature, basin water temperature, Wind Speed, and glass-out conditions. Regular recordings of these parameters were conducted from 09:00 a.m. to 05:00 p.m. to capture the dynamic changes and interactions throughout the specified time frame.

Figure 5 illustrates hourly variations in both wind speed and solar irradiation throughout the experiment, measured using an anemometer and Pyranometer. At 5:00 p.m., the recorded minimum irradiation was 437 W/m2, accompanied by a Wind Speed of 4.1 m/s. Conversely, the peak irradiation of 1143 W/m2 occurred at 1:00 p.m., coinciding with the maximum Wind Speed observed at 10 a.m. and 4 p.m., both at 5.1 m/s. These results underscore the dynamic interplay between solar irradiation and Wind Speed, showcasing fluctuations at different times of the day during the experimental period. Figure 6 depicts the temporal evolution of solar irradiation and ambient temperature. The highest ambient temperature, reaching 34 °C, is observed at 02:00 PM. simultaneously, the maximum irradiance is recorded at 1:00 PM, measuring 1143 W/m2. Conversely, the lowest ambient temperature, registering at 28 °C, occurs at 09:00 AM, while the incident irradiation reaches its minimum of 437 W/m2 at 5:00 PM. This graphical representation captures the dynamic interplay between solar irradiation and ambient temperature throughout the day.Figure 5 Hourly changes of wind speed and irradiance.

Figure 6 Hourly changes of solar irradiation and ambient temperature.

RSM optimization

The BFS Panel Fixation methodology, guided by RSM and CCD through a Quadratic model, systematically delved into the intricate dynamics of BFS power generation.

Three pivotal factors—panel height (A), water depth (B), and tilt angle (C)—were meticulously analyzed to unearth insights crucial for practical applications. The application of the quadratic model within CCD and frameworks enabled a comprehensive exploration of these factors. The ANOVA results, showcasing low p-values, underscored the statistical significance of Panel Height, Water Depth, and Tilt Angle, as well as their intricate interactions. The consideration of quadratic terms, namely A2, B2, and C2, shed light on the non-linear nuances inherent in the relationships between these variables. Numerically, the F-values, spanning from 5.49 to an impressive 2951.32, illustrated the magnitude of effects and their profound impact on system responses.

Fit statistics, including R-squared values approaching 1 (e.g., 0.98 for Output Power and 0.99 for Bi-Facial Gain), highlighted the models' adeptness in explaining response variability. Low standard deviations (10.47 and 8.00), coupled with minimal Coefficient of Variation percentages (3.07% and 1.38%), and underscored the precision of the models in predicting Output Power and Bi-Facial Gain, respectively in (Fig. 7). Simultaneously, the anticipated Bi-Facial Gain was 10.39, encapsulating a confidence interval of [10.17, 10.60]. The Confirmation Location results further validated the models, with observed values closely aligning with predictions and shown in (Fig. 8). At specific conditions, such as Panel Height 100 cm, Water Depth 6 cm, and Tilt Angle 90°, the observed output power of 397.68 W aligned closely with the predicted mean within the confidence interval [348.17, 447.18]. Similarly, the observed Bi-facial gain of 10.3891 fell within the predicted confidence interval [9.07, 11.71], affirming the accuracy of the models under specific conditions. The desirability remains constant at 1 across all conditions. This suggests that within the specified ranges of height, depth, and angle, the conditions consistently meet the desired criteria perfectly. It would be beneficial to review the desirability function settings, response goals, and constraints applied during optimization to ensure they are not set too leniently, which could lead to this uniform desirability. Adjusting these parameters might provide more informative variability in the desirability metric. Collectively, these findings not only emphasized the statistical significance of factors and interactions but also quantified the precision and accuracy of the models. The confirmed values at specific solution points, coupled with robust statistical measures, significantly enhanced the reliability and practical applicability of the developed models, providing a comprehensive numerical roadmap for optimizing BFS Power System through effective cooling methods.Figure 7 Predicated vs actual values of output power and bifacial gain.

Figure 8 Response surface methodology optimization final result.

Output power & bifacial gain analysis

The analysis of power output from BFS panels under varying conditions, comparing CWS with the PFS in (Fig. 9) reveals consistent and substantial improvements with the latter. Figure 9 illustrates the performance of bifacial solar cells under varying irradiance levels throughout the day. The data is presented in ascending-descending order, representing the natural progression of sunlight from morning to evening. This approach helps visualize the cells’ performance across different times of the day. Across all irradiation levels, PFW Surface consistently outperforms CWS, showcasing a maximum gain of 4.86% at 550 W/m2 irradiation in (Fig. 10). The power generated by PFS is consistently higher than CWS across all irradiation levels. On average, PFS exhibits approximately 1.5 to 2.95% higher power output compared to CWS, indicating the effectiveness of freshwater as a cooling method.Figure 9 Output power comparison.

Figure 10 Bifacial gain comparison.

Bifacial gain represents the increase in power output due to the bifacial nature of the solar panels. PFS consistently demonstrates higher bifacial gain compared to CWS, with an average gain ranging from 3.05 to 4.34%. This suggests that PFS enhances the efficiency of bifacial solar panels compared to CWS shown in (Fig. 10).

Power gain is the improvement in power output attributed to PFS compared to CWS. On average, PFS exhibits a power gain of approximately 1.39 to 2.95% compared to CWS, indicating the superior performance of PFS in power generation in (Fig. 11).Figure 11 Power gain percentage.

Bifacial gain indicates the increase in power output specifically attributed to the bifacial nature of the solar panels. PFS consistently demonstrates higher bifacial gain compared to CWS, with an average gain ranging from 3.05 to 4.34%. This highlights the enhanced efficiency of bifacial solar panels when coupled with PFS in (Fig. 12).Figure 12 Bifacial gain percentage.

Calculating the average gain across all irradiation levels further supports the superiority of the PFS system, with an overall gain percentage higher than that of CWS. This average gain signifies a robust and consistent enhancement in power output throughout varying environmental conditions. Additionally, the examination of maximum power values underscores that FW6 consistently achieves higher peak power values compared to CWS. This indicates that the proposed freshwater cooling system not only improves efficiency in terms of percentage gain but also results in higher absolute power production.

Temperature analysis

The comparative analysis of temperature variations between the PFS (PFW6) and CWS (CWS) reveals substantial differences under various irradiation conditions in (Figs. 13–15). The parameters considered for analysis include Panel Front Temperature (PFW F), Panel Back Temperature (PFW B), and Freshwater Reflector Temperature (PFW RF) for PFW6, while for CWS, Panel Front Temperature (CWS F), Panel Back Temperature (CWS R), and Reflector Temperature (CWS RF) are considered.Under irradiation conditions ranging from 500 W/m2 to 1000 W/m2, PFW6 consistently maintains lower temperatures for Panel Front, Panel Back, and Freshwater Reflector compared to their counterparts in CWS. The minimum irradiation condition at 500 W/m2 sees PFW6 with significantly lower temperatures across all parameters, illustrating its ability to mitigate heat more effectively.Figure 13 Panel front temperature comparison.

Figure 14 Panel back temperature comparison.

Figure 15 Reflector surface temperature comparison.

Analyzing specific irradiation levels, such as 700 W/m2, reveals that PFW6 achieves a Panel Front Temperature of 38.68 °C, while CWS registers a higher temperature at 47.6 °C. This temperature reduction in PFW6 is mirrored in Panel Back and Freshwater Reflector temperatures, further indicating the superior cooling efficiency of the PFS.The overall trend across all irradiation levels signifies that PFW6 consistently outperforms CWS in maintaining lower temperatures, showcasing the efficacy of the proposed freshwater cooling system. The percentage differences in temperatures highlight the notable thermal benefits of PFW6 over CWS, underscoring its potential for enhancing the efficiency and lifespan of BFS panels.

Cost analysis

The analysis of key financial metrics reveals compelling results for the proposed fresh water surface (PFW) compared to the conventional white paint surface (CWP) figured in (Fig. 16). While both surfaces incur identical module costs (Rs 18,120) and share the same cost of energy per kWh (Rs 8.5), PFW outshines CWP in peak power generation (393.72 kW vs. 388.31 kW). Daily energy generation and annual energy costs reflect the superior performance of PFW, producing 1.29 kWh daily compared to CWP's 1.26 kWh, with annual costs of Rs 4007.27 and Rs 3923.54, respectively shown in (Fig. 17). Despite marginally higher daily energy costs for PFW (Rs 10.98 vs. Rs 10.75 for CWP), the accelerated payback period of 4.52 years for PFW, as opposed to 4.62 years for CWP, underscores the economic viability and efficiency gains associated with the proposed fresh water surface for solar panel installations and shown in (Figs. 17, 18). Ref.35 indicates that FPV can achieve up to 2% higher energy yields than land-based systems, especially in warmer regions, though it may underperform if not adequately cooled. Cost competitiveness is achievable with reduced installation costs. Our results show nearly identical payback periods for CWS and PFS (4.618 and 4.522 years, respectively), with PFS being slightly cheaper in daily and annual energy generation costs, aligning with35’s findings. Additionally, Ref.36 emphasis on the cooling benefits of FPV matches the slight economic advantage seen in PFS, indicating potential efficiency gains.Figure 16 Payback period comparison.

Figure 17 Cost of daily energy generated.

Figure18 Cost of the energy generated per annum.

Conclusion

In conclusion, the application of RSM and CCD in the investigation of the floating BFS panel fixation methodology has yielded valuable insights for optimizing BFS power system.Analysis using panel height of 100 cm, water depth of 6 cm, and tilt angle of 90°, facilitated by a Quadratic model, revealed significant factors and interactions, predicting Output Power of 397.68 W and Bi-Facial Gain of 10.39 with high accuracy.

The PFS (FW6) consistently outperformed the CWS, showing a maximum power output gain of 4.86% at 550 W/m2 irradiation. This underscores the effectiveness of the freshwater cooling system in enhancing BFS panel efficiency.

Temperature analysis demonstrated that PFW6 maintained lower temperatures for Panel Front, Panel Back, and Freshwater Reflector compared to CWS across varying irradiation levels, indicating superior cooling efficiency.

With slightly higher daily energy costs (Rs 10.979 vs. Rs 10.75 for CWP), PFW offers a quicker payback period (4.52 vs. 4.62 years for CWP), highlighting its economic viability and efficiency.

This study quantifies power output increases and establishes a favorable comparison between the proposed freshwater cooling system and conventional approaches, emphasizing the potential of innovative cooling strategies for enhancing BFS panel performance.

Future research should focus on assessing long-term performance and durability of BFS panels under varied environmental conditions, optimizing cooling system designs for enhanced efficiency and cost-effectiveness, and exploring advanced materials to improve durability and energy absorption. These efforts will advance the practical application and sustainability of BFS technology in renewable energy systems both regulated and deregulated environment.

Author contributions

Conceptualization, Ganesan Rathinavel Pandian and Prince Winston David; Data curation, Ganesan Rathinavel Pandian; Funding acquisition, Sangeetha K; Investigation, Ganesan Rathinavel Pandian, Gurukarthik Babu Balachandran and Prince Winston David; Methodology, Gurukarthik Babu Balachandran; Project administration, Sangeetha K; Resources, Sangeetha K; Supervision, Gurukarthik Babu Balachandran and Sangeetha K; Validation, Gurukarthik Babu Balachandran and Prince Winston David; Writing—original draft, Ganesan Rathinavel Pandian; Writing—review & editing, Ganesan Rathinavel Pandian and Prince Winston David.

Data availability

The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.

Competing interests

The authors declare no competing interests.

Publisher's note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
==== Refs
References

1. Hasan A Dincer I A new performance assessment methodology of bifacial photovoltaic solar, panels for offshore applications Renew. Energy 2019 143 1698 1711 10.1016/j.renene.2019.06.055
Hasan, A. & Dincer, I. A new performance assessment methodology of bifacial photovoltaic solar, panels for offshore applications. Renew. Energy 143, 1698–1711. 10.1016/j.renene.2019.06.055 (2019).10.1016/j.renene.2019.06.055
2. Goswami A Sadhu PK Adoption of floating solar photovoltaics on waste water management system: A unique nexus of water-energy utilization, low-cost clean energy generation and water conservation J. Clean. Prod. 2020 247 119132 10.1016/j.jclepro.2019.119132
Goswami, A. & Sadhu, P. K. Adoption of floating solar photovoltaics on waste water management system: A unique nexus of water-energy utilization, low-cost clean energy generation and water conservation. J. Clean. Prod. 247, 119132. 10.1016/j.jclepro.2019.119132 (2020).10.1016/j.jclepro.2019.119132
3. Bahaidarah H Subhan A Gandhidasan P Rehman S Performance evaluation of a PV (photovoltaic) module by back surface water cooling for hot climatic conditions Energy 2013 59 562 570 10.1016/j.energy.2013.07.050
Bahaidarah, H., Subhan, A., Gandhidasan, P. & Rehman, S. Performance evaluation of a PV (photovoltaic) module by back surface water cooling for hot climatic conditions. Energy 59, 562–570 (2013).10.1016/j.energy.2013.07.050
4. Balachandran GB David PW Alexander AB A relative study on energy and exergy analysis between conventional single slope and novel stepped absorbable plate solar stills Environ. Sci. Pollut. Res. 2021 28 57602 57618 10.1007/s11356-021-14640-9
Balachandran, G. B. et al. A relative study on energy and exergy analysis between conventional single slope and novel stepped absorbable plate solar stills. Environ. Sci. Pollut. Res. 28, 57602–57618 (2021).10.1007/s11356-021-14640-9
5. Santos, F.L., Watanabe, M.N., Chiappim, W., dos Santos Filho, S.G. & Martino, J.A. Bifacial Tandem Solar Panels with MOS Cells on the Backside for Applications in Deserts. In: 2019 34th Symposium on Microelectronics Technology and Devices (SBMicro) (pp. 1–4) (IEEE, 2019).
6. Song BP Zhang MY Fan Y Jiang L Kang J Gou TT Zhang CL Yang N Zhang GJ Zhou X End-of-life management of bifacial solar panels using high-voltage fragmentation as pretreatment approach Sol. Energy 2020 206 379 388
Song, B. P. et al. End-of-life management of bifacial solar panels using high-voltage fragmentation as pretreatment approach. Sol. Energy 206, 379–388 (2020).
7. Sugiura T Matsumoto S Nakano N Optimization of front diffusion profile in bifacial interdigitated back contact solar cell IEEE J. Photovolt. 2020 10 2 357 362
Sugiura, T., Matsumoto, S. & Nakano, N. Optimization of front diffusion profile in bifacial interdigitated back contact solar cell. IEEE J. Photovolt. 10(2), 357–362 (2020).
8. Claus R López M Key issues in the design of floating photovoltaic structures for the marine environment Renew. Sustain. Energy Rev. 2022 164 112502 10.1016/j.rser.2022.112502
Claus, R. & López, M. Key issues in the design of floating photovoltaic structures for the marine environment. Renew. Sustain. Energy Rev. 164, 112502 (2022).10.1016/j.rser.2022.112502
9. El Majid B Motahhir S El Ghzizal A Parabolic bifacial solar panel with the cooling system: Concept and challenges SN Appl. Sci. 2019 1 10 1176 10.1007/s42452-019-1223-8
El Majid, B., Motahhir, S. & El Ghzizal, A. Parabolic bifacial solar panel with the cooling system: Concept and challenges. SN Appl. Sci. 1(10), 1176 (2019).10.1007/s42452-019-1223-8
10. Farrar LW Bahaj AS James P Anwar A Amdar N Floating solar PV to reduce water evaporation in water stressed regions and powering water pumping: Case study Jordan Energy Convers. Manag. 2022 260 115598 10.1016/j.enconman.2022.115598
Farrar, L. W., Bahaj, A. S., James, P., Anwar, A. & Amdar, N. Floating solar PV to reduce water evaporation in water stressed regions and powering water pumping: Case study Jordan. Energy Convers. Manag. 260, 115598 (2022).10.1016/j.enconman.2022.115598
11. Ghenai C Ahmad FF Rejeb O Hamid AK Sensitivity analysis of design parameters and power gain correlations of bi-facial solar PV system using response surface methodology Sol. Energy 2021 223 44 53 10.1016/j.solener.2021.05.024
Ghenai, C., Ahmad, F. F., Rejeb, O. & Hamid, A. K. Sensitivity analysis of design parameters and power gain correlations of bi-facial solar PV system using response surface methodology. Sol. Energy 223, 44–53 (2021).10.1016/j.solener.2021.05.024
12. Goswami A Sadhu PK Nature inspired evolutionary algorithm integrated performance assessment of floating solar photovoltaic module for low-carbon clean energy generation Sustain. Oper. Comput. 2022 3 67 82 10.1016/j.susoc.2021.10.002
Goswami, A. & Sadhu, P. K. Nature inspired evolutionary algorithm integrated performance assessment of floating solar photovoltaic module for low-carbon clean energy generation. Sustain. Oper. Comput. 3, 67–82 (2022).10.1016/j.susoc.2021.10.002
13. Guerrero-Lemus RVTKAKLSR Vega R Kim T Kimm A Shephard LE Bifacial solar photovoltaics–A technology review Renew. Sustain. Energy Rev. 2016 60 1533 1549 10.1016/j.rser.2016.03.041
Guerrero-Lemus, R. V. T. K. A. K. L. S. R., Vega, R., Kim, T., Kimm, A. & Shephard, L. E. Bifacial solar photovoltaics–A technology review. Renew. Sustain. Energy Rev. 60, 1533–1549 (2016).10.1016/j.rser.2016.03.041
14. Hasan A Dincer I A new performance assessment methodology of bifacial photovoltaic solar panels for offshore applications Energy Convers. Manag. 2020 220 112972 10.1016/j.enconman.2020.112972
Hasan, A. & Dincer, I. A new performance assessment methodology of bifacial photovoltaic solar panels for offshore applications. Energy Convers. Manag. 220, 112972 (2020).10.1016/j.enconman.2020.112972
15. Hu M Zhao B Ao X Cao J Wang Q Riffat S Su Y Pei G Performance analysis of a novel bifacial solar photothermic and radiative cooling module Energy Convers. Manag. 2021 236 114057 10.1016/j.enconman.2021.114057
Hu, M. et al. Performance analysis of a novel bifacial solar photothermic and radiative cooling module. Energy Convers. Manag. 236, 114057 (2021).10.1016/j.enconman.2021.114057
16. Jahangir JB Shams A Javed MS Khan MS A critical analysis of bifacial solar farm configurations: Theory and experiments Energies 2019 12 4114 10.3390/en12214114
Jahangir, J. B., Shams, A., Javed, M. S. & Khan, M. S. A critical analysis of bifacial solar farm configurations: Theory and experiments. Energies 12, 4114. 10.3390/en12214114 (2019).10.3390/en12214114
17. Ganesan K Prince Winston D Sugumar S Jegan S Performance analysis of n-type PERT bifacial solar PV module under diverse albedo conditions Sol. Energy 2023 252 81 90 10.1016/j.solener.2023.01.020
Ganesan, K., Prince Winston, D., Sugumar, S. & Jegan, S. Performance analysis of n-type PERT bifacial solar PV module under diverse albedo conditions. Sol. Energy 252, 81–90 (2023).10.1016/j.solener.2023.01.020
18. Karatas Y Yilmaz D Experimental investigation of the microclimate effects on floating solar power plant energy efficiency Sol. Energy 2021 221 227 235
Karatas, Y. & Yilmaz, D. Experimental investigation of the microclimate effects on floating solar power plant energy efficiency. Sol. Energy 221, 227–235 (2021).
19. Kichou S Skandalos N Wolf P Floating photovoltaics performance simulation approach Heliyon 2022 8 12 e11896 10.1016/j.heliyon.2022.e11896 36471850
Kichou, S., Skandalos, N. & Wolf, P. Floating photovoltaics performance simulation approach. Heliyon 8(12), e11896 (2022).36471850 10.1016/j.heliyon.2022.e11896
20. Liu H Krishna V Lun Leung J Reindl T Zhao L Field experience and performance analysis of floating PV technologies in the tropics Prog. Photovolt. Res. Appl. 2018 26 12 957 967 10.1002/pip.3039
Liu, H., Krishna, V., Lun Leung, J., Reindl, T. & Zhao, L. Field experience and performance analysis of floating PV technologies in the tropics. Prog. Photovolt. Res. Appl. 26(12), 957–967 (2018).10.1002/pip.3039
21. Luo W Wang J Li M Li Q Li S Xie J Yu B Li W Performance loss rates of floating photovoltaic installations in the tropics Appl. Energy 2021 283 116352
Luo, W. et al. Performance loss rates of floating photovoltaic installations in the tropics. Appl. Energy 283, 116352 (2021).
22. L´opez M Soto F Hern´andez ZA Assessment of the potential of floating solar photovoltaic panels in bodies of water in mainland Spain Energy Convers. Manag. 2019 188 225 235 10.1016/j.enconman.2019.03.011
L´opez, M., Soto, F. & Hern´andez, Z. A. Assessment of the potential of floating solar photovoltaic panels in bodies of water in mainland Spain. Energy Convers. Manag. 188, 225–235. 10.1016/j.enconman.2019.03.011 (2019).10.1016/j.enconman.2019.03.011
23. Tahir Patel M Ryyan Khan M Suna X Muhammad AA A worldwide cost-based design and optimization of tilted bifacial solar farms Appl. Energy 2020 268 114956 10.1016/j.apenergy.2020.114956
Tahir Patel, M., Ryyan Khan, M., Suna, X. & Muhammad, A. A. A worldwide cost-based design and optimization of tilted bifacial solar farms. Appl. Energy 268, 114956. 10.1016/j.apenergy.2020.114956 (2020).10.1016/j.apenergy.2020.114956
24. Rüdiger M Fischer S Frank J Ivaturi A Richards BS Karl WK Hermle M Goldschmidt JC Bifacial n-type silicon solar cells for upconversion applications Sol. Energy Mater. Sol. Cells 2018 174 261 269 10.1016/j.solmat.2017.10.026
Rüdiger, M. et al. Bifacial n-type silicon solar cells for upconversion applications. Sol. Energy Mater. Sol. Cells 174, 261–269. 10.1016/j.solmat.2017.10.026 (2018).10.1016/j.solmat.2017.10.026
25. Muehleisen W Loeschnig J Feichtner M Burgers AR Bende EE Zamini S Yerasimou Y Kosel J Hirschl C Georghiou GE Energy yield measurement of an elevated PV system on a white flat roof and a performance comparison of monofacial and bifacial modules Sol. Energy 2020 209 12 23
Muehleisen, W. et al. Energy yield measurement of an elevated PV system on a white flat roof and a performance comparison of monofacial and bifacial modules. Sol. Energy 209, 12–23 (2020).
26. Pounraj P Prince Winston D Kabeel AE Praveen Kumar B MuthuManokar A RavishankarSathyamurthy S Christabel C Experimental investigation on peltier based hybrid PV/T active solar still for enhancing the overall performance Energy Convers. Manag. 2018 168 371 381 10.1016/j.enconman.2018.05.011
Pounraj, P. et al. Experimental investigation on peltier based hybrid PV/T active solar still for enhancing the overall performance. Energy Convers. Manag. 168, 371–381 (2018).10.1016/j.enconman.2018.05.011
27. Patel MT Ahmed MS Imran H Butt NZ Khan MR Alam MA Global analysis of next-generation utility-scale PV: Tracking bifacial solar farms Renew. Energy 2021 164 257 268
Patel, M. T. et al. Global analysis of next-generation utility-scale PV: Tracking bifacial solar farms. Renew. Energy 164, 257–268 (2021).
28. Qader BS Supeni EE Ariffin MKA Talib AA RSM approach for modeling and optimization of designing parameters for inclined fins of solar air heater Renew. Energy 2019 136 48 68 10.1016/j.renene.2018.12.099
Qader, B. S., Supeni, E. E., Ariffin, M. K. A. & Talib, A. A. RSM approach for modeling and optimization of designing parameters for inclined fins of solar air heater. Renew. Energy 136, 48–68 (2019).10.1016/j.renene.2018.12.099
29. Mohr A Roth T Glunz SW BICON: High concentration PV using one-axis tracking and silicon concentrator cells Prog. Photovolt. Res. Appl. 2006 14 7 663 674 10.1002/pip.691
Mohr, A., Roth, T. & Glunz, S. W. BICON: High concentration PV using one-axis tracking and silicon concentrator cells. Prog. Photovolt. Res. Appl. 14(7), 663–674 (2006).10.1002/pip.691
30. Arnaoutakis GE Marques-Hueso J Ivaturi A Krämer KW Fischer S Goldschmidt JC Richards BS Enhanced up-conversion for photovoltaics via concentrating integrated optics Opt. Express 2014 22 102 A452 A464 10.1364/OE.22.00A452 24922255
Arnaoutakis, G. E. et al. Enhanced up-conversion for photovoltaics via concentrating integrated optics. Opt. Express 22(102), A452–A464 (2014).24922255 10.1364/OE.22.00A452
31. Lehr J Langenhorst M Schmager R Gota F Kirner S Lemmer U Richards BS Case C Paetzold UW Energy yield of bifacial textured perovskite/silicon tandem photovoltaic modules Sol. Energy Mater. Sol. Cells 2020 208 110367 10.1016/j.solmat.2019.110367
Lehr, J. et al. Energy yield of bifacial textured perovskite/silicon tandem photovoltaic modules. Sol. Energy Mater. Sol. Cells 208, 110367 (2020).10.1016/j.solmat.2019.110367
32. Arnaoutakis GE Favilla E Tonelli M Richards BS Single crystal monolithic upconverter solar cell device tandems with integrated optics J. Opt. Soc. Am. B 2022 39 1 239 247 10.1364/JOSAB.437892
Arnaoutakis, G. E., Favilla, E., Tonelli, M. & Richards, B. S. Single crystal monolithic upconverter solar cell device tandems with integrated optics. J. Opt. Soc. Am. B 39(1), 239–247 (2022).10.1364/JOSAB.437892
33. Smith S Mitterhofer S Moffitt SL Jhang SS Watson SS Sung LP Gu X Long-term durability of transparent backsheets for bifacial photovoltaics: An in-depth degradation analysis Sol. Energy Mater. Sol. Cells 2023 256 112309 10.1016/j.solmat.2023.112309
Smith, S. et al. Long-term durability of transparent backsheets for bifacial photovoltaics: An in-depth degradation analysis. Sol. Energy Mater. Sol. Cells 256, 112309 (2023).10.1016/j.solmat.2023.112309
34. Liang TS Pravettoni M Deline C Stein JS Kopecek R Singh JP Luo W Wang Y Aberle AG Khoo YS A review of crystalline silicon bifacial photovoltaic performance characterisation and simulation Energy Environ. Sci. 2019 12 1 116 148 10.1039/C8EE02184H
Liang, T. S. et al. A review of crystalline silicon bifacial photovoltaic performance characterisation and simulation. Energy Environ. Sci. 12(1), 116–148 (2019).10.1039/C8EE02184H
35. Micheli L Talavera DL Tina GM Almonacid F Fernández EF Techno-economic potential and perspectives of floating photovoltaics in Europe Sol. Energy 2022 243 203 214 10.1016/j.solener.2022.07.042
Micheli, L., Talavera, D. L., Tina, G. M., Almonacid, F. & Fernández, E. F. Techno-economic potential and perspectives of floating photovoltaics in Europe. Sol. Energy 243, 203–214 (2022).10.1016/j.solener.2022.07.042
36. Tina GM Scavo FB Micheli L Rosa-Clot M Economic comparison of floating photovoltaic systems with tracking systems and active cooling in a Mediterranean water basin Energy Sustain. Dev. 2023 76 101283 10.1016/j.esd.2023.101283
Tina, G. M., Scavo, F. B., Micheli, L. & Rosa-Clot, M. Economic comparison of floating photovoltaic systems with tracking systems and active cooling in a Mediterranean water basin. Energy Sustain. Dev. 76, 101283 (2023).10.1016/j.esd.2023.101283
