Search Results (41)

This paper investigates the performance of a spacecraft equipped with a diffractive sail in a heliocentric mission scenario that requires phasing along a prescribed elliptical orbit. The diffractive sail represents an evolution of the more traditional reflective solar sail, which converts solar radiation pressure into thrust using a large reflective surface typically coated with a thin metallic film. In contrast, the diffractive sail proposed by Swartzlander leverages the properties of an advanced metamaterial-based film to generate a net transverse thrust even when the sail is Sun-facing, i.e., in a configuration that can be passively maintained by a suitably designed spacecraft. Specifically, this study considers a sail membrane covered with a set of electro-optically controlled diffractive panels. These panels employ a (controlled) binary metamaterial arrayed grating to steer the direction of photons exiting the diffractive film. This control technique has recently been applied to achieve a circle-to-circle interplanetary transfer using a Sun-facing diffractive sail. In this work, an optimal control law is employed to execute a rapid phasing maneuver along an elliptical heliocentric orbit with specified characteristics, such as those of Earth and Mercury. The analysis also includes a limiting case involving a circular heliocentric orbit. For this latter scenario, a simplified and elegant control law is proposed based on a linearized form of the equations of motion to describe the heliocentric dynamics of the diffractive sail-based spacecraft during the phasing maneuver. Full article

Accurate estimation of available rooftop areas for PV power generation at the city scale is critical for sustainable energy planning and policy development. In this study, using publicly available high-resolution satellite imagery, rooftop solar energy potential in urban, rural, and industrial areas is estimated using deep learning models. In order to identify roof areas, high-resolution open-source images were manually labeled, and the training dataset was trained with DeepLabv3+ architecture. The developed model performed roof area detection with high accuracy. Model outputs are integrated with a user-friendly interface for economic analysis such as cost, profitability, and amortization period. This interface automatically detects roof regions in the bird’s-eye -view images uploaded by users, calculates the total roof area, and classifies according to the potential of the area. The system, which is applied in 81 provinces of Turkey, provides sustainable energy projections such as PV installed capacity, installation cost, annual energy production, energy sales revenue, and amortization period depending on the panel type and region selection. This integrated system consists of a deep learning model that can extract the rooftop area with high accuracy and a user interface that automatically calculates all parameters related to PV installation for energy users. The results show that the DeepLabv3+ architecture and the Adam optimization algorithm provide superior performance in roof area estimation with accuracy between 67.21% and 99.27% and loss rates between 0.6% and 0.025%. Tests on 100 different regions yielded a maximum roof estimation accuracy IoU of 84.84% and an average of 77.11%. In the economic analysis, the amortization period reaches the lowest value of 4.5 years in high-density roof regions where polycrystalline panels are used, while this period increases up to 7.8 years for thin-film panels. In conclusion, this study presents an interactive user interface integrated with a deep learning model capable of high-accuracy rooftop area detection, enabling the assessment of sustainable PV energy potential at the city scale and easy economic analysis. This approach is a valuable tool for planning and decision support systems in the integration of renewable energy sources. Full article

Solar photovoltaic (PV) systems in buildings must comply with both electrotechnical standards for module safety and local building codes, which typically do not address their electrical nature. This regulatory gap creates challenges in assessing the fire performance of PV systems. This paper presents a procedure to adapt a common test method used in some building codes to assess external fire conditions for roofs, while maintaining operative PV modules. Two configurations were tested: an organic PV thin film on a metallic sandwich panel and a glass–glass-encapsulated organic PV module. The tests were conducted under high voltage and current conditions to simulate the systems’ behavior within a larger PV array. Significant electric arcs were observed during testing of the metallic sandwich panel configuration without glass protection when subjected to high voltages or currents. In these cases, total heat release increased by at least 30% compared to non-electrically loaded scenarios or glass-insulated PV modules, likely due to a greater damaged surface area. Electric arcs created new ignition sources, damaging whole PV modules, whereas in the case with no electrical load, propagation flames advanced toward both the upper edge and the corners of the sample, ultimately damaging the entire triangular area above the fire source. The results indicate that the electrical characteristics of PV systems can significantly impact external fire spread behavior. The study identifies challenges in maintaining system activity during testing and simulating real scenarios and proposes for future research directions. Full article

The European Union’s Green Deal concept prioritizes the installation of photovoltaic and wind turbine systems, with the aim of significantly reducing greenhouse gas emissions and expanding the use of renewable energy. The inclusion of metals/metaloids such as Cd, Pb, Ni, and As to PV panels may be a matter of concern because they may provoke numerous negative environmental effects, especially after decommissioning. Although the release of Pb and Cd from solar panels is generally low, these releases may increase, posing long-term harm. Cd and Pb, if only released from solar panels, can enter the environment, including soil and water, posing a significant risk to human health and ecosystems. Cd, in particular, can have profound and lasting negative impacts on animals and humans, affecting cellular responses, enzyme operations, and immune system functionality. Pb exposure, in turn, can induce oxidative stress and neurotoxicity, disrupt ion regulatory pathways, and impair immune function. Despite efforts to reduce the release of toxic metals from PV panels, controlling their disposal and avoiding environmental contamination remains challenging. Discovering substitute materials for PV panel manufacture, implementing enhanced recycling procedures, performing bioremediation, and enforcing stronger restrictions are among the strategies to mitigate environmental concerns. Full article

In the dynamic field of photovoltaic technology, the pursuit of efficiency and sustainability has led to continuous novelty, shaping the landscape of solar energy solutions. One of the key elements affecting the efficiency of photovoltaic cells of II^nd and III^rd generation is the presence of transparent conductive oxide (TCO) layers, which are key elements impacting the efficiency and durability of solar panels, especially for DSSC, CdTe, CIGS (copper indium gallium diselenide) or organic, perovskite and quantum dots. TCO with low electrical resistance, high mobility, and high transmittance in the VIS–NIR region is particularly important in DSSC, CIGS, and CdTe solar cells, working as a window and electron transporting layer. This layer must form an ohmic contact with the adjacent layers, typically the buffer layer (such as CdS or ZnS), to ensure efficient charge collection Furthermore it ensures protection against oxidation and moisture, which is especially important when transporting the active cell structure to further process steps such as lamination, which ensures the final seal. Transparent conductive oxide layers, which typically consist of materials such as indium tin oxide (ITO) or alternatives such as fluorine-doped tin oxide (FTO), serve dual purposes in photovoltaic applications. Primarily located as the topmost layer of solar cells, TCOs play a key role in transmitting sunlight while facilitating the efficient collection and transport of generated electrical charges. This complex balance between transparency and conductivity highlights the strategic importance of TCO layers in maximizing the performance and durability of photovoltaic systems. As the global demand for clean energy increases and the photovoltaic industry rapidly develops, understanding the differential contribution of TCO layers becomes particularly important in the context of using PV modules as building-integrated elements (BIPV). The use of transparent or semi-transparent modules allows the use of building glazing, including windows and skylights. In addition, considering the dominant position of the Asian market in the production of cells and modules based on silicon, the European market is intensifying work aimed at finding a competitive PV technology. In this context, thin-film, organic modules may prove competitive. For this purpose, in this work, we focused on the electrical parameters of two different thicknesses of a transparent FTO layer. First, the influence of the FTO layer thickness on the transmittance over a wide range was verified. Next, the chemical composition was determined, and key electrical parameters, including carrier mobility, resistivity, and the Hall coefficient, were determined. Full article

Ultra-thin solar cells enable materials to be saved, reduce deposition time, and promote carrier collection from materials with short diffusion lengths. However, light absorption efficiency in ultra-thin solar panels remains a limiting factor. Most methods to increase light absorption in ultra-thin solar cells are either technically challenging or costly, given the thinness of the functional layers involved. We propose a cost-efficient and lithography-free solution to enhance light absorption in ultra-thin solar cells—a Tsuchime-like self-forming nanocrater (T-NC) aluminum (Al) film. T-NC Al film can be produced by the electrochemical anodization of Al, followed by etching the nanoporous alumina. Theoretical studies show that T-NC film can increase the average absorbance by 80.3%, depending on the active layer’s thickness. The wavelength range of increased absorption varies with the active layer thickness, with the peak of absolute absorbance increase moving from 620 nm to 950 nm as the active layer thickness increases from 500 nm to 10 µm. We have also shown that the absorbance increase is retained regardless of the active layer material. Therefore, T-NC Al film significantly boosts absorbance in ultra-thin solar cells without requiring expensive lithography, and regardless of the active layer material. Full article

Dust accumulation on a PV panel surface can considerably lead to photovoltaic energy degradation. A particle-based dust accumulation model was proposed to estimate the surface dust coverage fraction on a PV panel. The model determines the effect of the surface dust coverage fraction on the performance of the PV panel. Gravity, wind, and particle-surface interaction forces were resolved to their components, and force balance was established to determine surface-parallel (slipping force) and surface-orthogonal (adhering force) component forces. The proposed model was validated through a schedule of lab and field experiments and by comparing the predicted values with the results of a validated model developed by Lu and Hajimirza. The relationship between a solar panel’s output power and the surface dust coverage fraction under the wind effect was established for three types of dust (graphene, silica, and natural dust) using Response Surface Methodology (RSM). Statistical analysis was applied to determine the most and least influencing variables on the output power of three types of solar panels (mono-crystalline, polycrystalline, and thin-film PV panels) exposed to dust accumulation. The obtained results show that dust particle size, wind velocity, and PV panel tilt angle play important roles in enhancing or degrading PV performance. Lower values of the tilt angle resulted in maximum output power, while high values of the tilt angle reduced the incident sunlight on the surface of the PV panel, resulting in lower output power. However, higher values of the tilt angle led to a lower dust coverage area of the PV panel and consequently decreased the power losses of the PV panel. The results also show that wind velocity has a considerable impact on the dust scraping of fine particles from a PV surface. The enhancement percentages of PV performance due to wind influence are 4.85%, 5.85%, and 10.9% for graphene, silica, and natural dust, respectively. Full article

The rapid growth and evolution of solar panel technology have been driven by continuous advancements in materials science. This review paper provides a comprehensive overview of the diverse range of materials employed in modern solar panels, elucidating their roles, properties, and contributions to overall performance. The discussion encompasses both traditional crystalline silicon-based panels and emerging thin-film technologies. A detailed examination of photovoltaic materials, including monocrystalline and polycrystalline silicon as well as alternative materials such as cadmium telluride (CdTe), copper indium gallium selenide (CIGS), and emerging perovskite solar cells, is presented. Furthermore, the impact of transparent conductive materials, encapsulation polymers, and antireflective coatings on solar panel efficiency and durability is explored. The review delves into the synergistic interplay between material properties, manufacturing processes, and environmental considerations. Through a comprehensive survey of materials utilized in modern solar panels, this paper provides insights into the current state of the field, highlighting avenues for future advancements and sustainable solar energy solutions. Full article

Thin films of tin (II) sulfide (SnS) were deposited onto a 500 µm thick copper substrate by a chemical bath method. The effect of sodium (Na) doping in these films was studied. The synthesis of the films was performed at temperatures of 60, 70, and 80 °C for 5 min. The microstructure of the SnS films analyzed by scanning electron microscopy (SEM) showed a compact morphology of the films deposited at 80 °C. The edges of the SnS grains were rounded off with the addition of a commercial surfactant. The thickness of different SnS layers deposited on the copper substrate was found to be 230 nm from spectroscopic ellipsometry and cross-section analysis using SEM. The deposition parameters such as temperature, surfactant addition, and sodium doping time did not affect the thickness of the layers. From the X-ray diffraction (XRD) analysis, the size of the SnS crystallites was found to be around 44 nm. Depending on the process conditions, Na doping affects the size of the crystallites in different ways. A study of the conductivity of SnS films provides a specific conductivity value of 0.3 S. The energy dispersive analysis of X-rays (EDAX) equipped with the SEM revealed the Sn:S stoichiometry of the film to be 1:1, which was confirmed by the X-ray photoelectron spectroscopy (XPS) analysis. The determined band-gap of SnS is equal to 1.27 eV and is in good agreement with the literature data. Full article

The aim of this paper is to analyze the transfer performance of a spacecraft whose primary propulsion system is a diffractive solar sail with active, switchable panels. The spacecraft uses a propellantless thruster that converts the solar radiation pressure into propulsive acceleration by taking advantage of the diffractive property of an electro-optically controlled (binary) metamaterial. The proposed analysis considers a heliocentric mission scenario where the spacecraft is required to perform a two-dimensional transfer between two concentric and coplanar circular orbits. The sail attitude is assumed to be Sun-facing, that is, with its sail nominal plane perpendicular to the incoming sunlight. This is possible since, unlike a more conventional solar sail concept that uses metalized highly reflective thin films to reflect the photons, a diffractive sail is theoretically able to generate a component of the thrust vector along the sail nominal plane also in a Sun-facing configuration. The electro-optically controlled sail film is used to change the in-plane component of the thrust vector to accomplish the transfer by minimizing the total flight time without changing the sail attitude with respect to an orbital reference frame. This work extends the mathematical model recently proposed by the authors by including the potential offered by an active control of the diffractive sail film. The paper also thoroughly analyzes the diffractive sail-based spacecraft performance in a set of classical circle-to-circle heliocentric trajectories that model transfers from Earth to Mars, Venus and Jupiter. Full article

The problem with waste heat in solar panels has stimulated research on materials suitable for hybrid solar cells, which combine photovoltaic and thermoelectric properties. One such potential material is Cu₂ZnSnS₄ (CZTS). Here, we investigated thin films formed from CZTS nanocrystals obtained by “green” colloidal synthesis. The films were subjected to thermal annealing at temperatures up to 350 °C or flash-lamp annealing (FLA) at light-pulse power densities up to 12 J/cm². The range of 250–300 °C was found to be optimal for obtaining conductive nanocrystalline films, for which the thermoelectric parameters could also be determined reliably. From phonon Raman spectra, we conclude that in this temperature range, a structural transition occurs in CZTS, accompanied by the formation of the minor Cu_xS phase. The latter is assumed to be a determinant for both the electrical and thermoelectrical properties of CZTS films obtained in this way. For the FLA-treated samples, the film conductivity achieved was too low to measure the thermoelectric parameters reliably, although the partial improvement of the CZTS crystallinity is observed in the Raman spectra. However, the absence of the Cu_xS phase supports the assumption of its importance with respect to the thermoelectric properties of such CZTS thin films. Full article

Nanosatellites have established their importance in low-Earth orbit (LEO), and it is common for student teams to build them for educational and technology demonstration purposes. The next challenge is the technology maturity for deep-space missions. The LEO serves as a relevant environment for maturing the spacecraft design. Here we present the ESTCube-2 mission, which will be launched onboard VEGA-C VV23. The satellite was developed as a technology demonstrator for the future deep-space mission by the Estonian Student Satellite Program. The ultimate vision of the program is to use the electric solar wind sail (E-sail) technology in an interplanetary environment to traverse the solar system using lightweight propulsion means. Additional experiments were added to demonstrate all necessary technologies to use the E-sail payload onboard ESTCube-3, the next nanospacecraft targeting the lunar orbit. The E-sail demonstration requires a high-angular velocity spin-up to deploy a tether, resulting in a need for a custom satellite bus. In addition, the satellite includes deep-space prototypes: deployable structures; compact avionics stack electronics (including side panels); star tracker; reaction wheels; and cold–gas propulsion. During the development, two additional payloads were added to the design of ESTCube-2, one for Earth observation of the Normalized Difference Vegetation Index and the other for corrosion testing in the space of thin-film materials. The ESTCube-2 satellite has been finished and tested in time for delivery to the launcher. Eventually, the project proved highly complex, making the team lower its ambitions and optimize the development of electronics, software, and mechanical structure. The ESTCube-2 team dealt with budgetary constraints, student management problems during a pandemic, and issues in the documentation approach. Beyond management techniques, the project required leadership that kept the team aware of the big picture and willing to finish a complex satellite platform. The paper discusses the ESTCube-2 design and its development, highlights the team’s main technical, management, and leadership issues, and presents suggestions for nanosatellite and nanospacecraft developers. Full article

A review on ceramics, glasses and glass–ceramics as thin film protective coatings for solar cells is given. The different preparation techniques and the physical and chemical properties are presented in a comparative way. This study is useful for technologies involving solar cells and solar panel cell development at the industrial scale, because protective coatings and encapsulation play a major role in increasing the lifetime of solar panels and environmental protection. The aim of this review article is to give a summary of existing ceramic, glass, and glass–ceramic protective coatings and how they apply to solar cell technology: silicon, organic or perovskite cells. Moreover, some of these ceramic, glass or glass–ceramic layers were found to have dual functionality, such as providing anti-reflectivity or scratch resistance to give a two-fold improvement to the lifetime and efficiency of the solar cell. Full article

For extracting the equivalent circuit parameters of solar photovoltaic (PV) panels, a unique bio-inspired swarm intelligence optimisation algorithm (OA) called the dandelion optimisation algorithm (DOA) is proposed in this study. The suggested approach has been used to analyse well-known single-diode (SD) and double-diode (DD) PV models for several PV module types, including monocrystalline SF430M, polycrystalline SG350P, and thin-film Shell ST40. The DOA is adopted by minimizing the sum of the squares of the errors at three locations (short-circuit, open-circuit, and maximum power points). Different runs are conducted to analyse the nature of the extracted parameters and the V–I characteristics of the PV panels under consideration. Obtained results show that for Mono SF430M, the error in the SD model is 2.5118e-19, and the error in the DD model is 2.0463e-22; for Poly SG350P, the error in the SD model is 9.4824e-21, and the error in the DD model is 2.1134e-20; for thin-film Shell ST40, the error in the SD model is 1.7621e-20, and the error in DD model is 7.9361e-22. The parameters produced from the suggested method yield the least amount of error across several executions, which suggests its better implementation in the current situation. Furthermore, statistical analysis of the SD and DD models using DOA is also carried out and compared with two hybrid OAs in the literature. Statistical results show that the standard deviation, sum, mean, and variance of various PV panels using DOA are lower compared to those of the other two hybrid OAs. Full article

Conventionally accessible silicon solar cells experience two major drawbacks, such as reduced efficiency and increased fabrication costs. The prospects for the reduction in the cost of the photovoltaic form of energy conversion are bifacial solar cells. Bifacial solar cells show potential opportunity in reducing the cost of solar energy conversion when analyzed with respect to monofacial cells. The bifacial solar cells exploit sunlight occurrence on both sides of the cell more efficiently. Bifacial-based solar photovoltaic (PV) is a technology that increases the generation of electrical energy per square meter of PV module through the utilization of light absorption from the albedo. This technology can generally be categorized based on the type of solar cell material and the fabrication technique. PV devices are classified as a silicon-based, thin film, organic, and advanced nano PV. This paper takes a second look at some recent initiatives and significant issues in enhancing the efficiency of bifacial solar cells from material sciences and chemical composition aspects. From this review, it is concluded that screen-printed solar cells have produced a maximum efficiency of 22%. Additionally, triode structure single-crystalline cells produced a maximum front side efficiency of 21.3% and rear side efficiency of 19.8%. Considering the recycling of solar panels, organic solar panels can be developed. Full article