Solar Energy最新文献

Plasmonic solar cells are desirable because of their high efficiency and cost-effectiveness compared to second-generation solar cells. In this research, the photoanode of cadmium chalcogenide quantum dot-sensitized solar cells (QDSSCs) was modified by growing gold nanoparticles (AuNPs) arrays on the Fluorine-doped Tin Oxide (FTO) coated glass slide. To fabricate plasmonic nanoparticle arrays, the colloidal lithography technique applying monodisperse polymeric microspheres was used. A monolayer of Poly (methyl methacrylate) (PMMA) microspheres, as a template, was deposited on the substrate using the gas–liquid interface deposition technique. Then, a thin film of Au with different thicknesses was deposited on the template using the magnetron sputtering method. After removing the polymeric template by calcination and chemical etching methods, homogeneous arrays of AuNPs remained on the FTO surface. Then, solar cells sensitized with ternary CdS_1-xSe_x quantum dots (QDs) were fabricated with the structure of FTO-AuNPs/TiO₂/CdS_1-xSe_x. Photovoltaic (PV) parameters were strengthened by increasing light absorption, electron extraction, and decreasing recombination rate (J_sc = 19.95 mA cm⁻², V_oc = 0.55 V, FF = 0.54).

This article presents a realistic and novel method to estimate the solar radiant flux collected by the receiver of a solar power tower (SPT) system, taking into account the detailed atmospheric radiative transfer. It describes how an atmospheric radiative transfer Monte Carlo code is modified to solve the radiative transfer both in the atmosphere and within the concentrating system consisting of the heliostat field and the receiver. To validate the geometric modeling of a complete SPT (624 heliostats with 24 facets) as well as the estimation of its optical efficiency (both independent of the atmosphere), a comparison with the reference ray-tracing code “Solstice” is presented for two times of the day, two solar disk half-angles, and two heliostat surface slope errors. This new model allows the estimation of not only the optical losses but also, as in Moulana (2019), the gains due to atmospheric and environmental contributions i.e., radiant flux from circumsolar, aerosol scattering, ground reflection, etc. Annual average results (with a numerical uncertainty less than 0.01%) under clear sky conditions (without clouds) show that the gains are not negligible and could reach up to 0.414 MW (1.08% of the radiant flux collected by the receiver) for a relatively small SPT located in a desert area.

Accurate photovoltaic power prediction is crucial for reducing the uncertainty of photovoltaic systems in grid operation. Variations in cloud cover are one of the primary factors leading to fluctuations in photovoltaic power generation. However, clouds possess highly complex three-dimensional structures. Existing photovoltaic power prediction methods typically rely on two-dimensional cloud images, which are insufficient for fully capturing the impact of clouds on photovoltaic power generation. To address these challenges, this paper proposes a Multi-source data Photovoltaic power Prediction Model (MPPM) based on satellite cloud images and meteorological data. MPPM mainly includes SpatioTemporal feature Conditional Diffusion Model (STCDM), Attention Stacked LSTM network (ASLSTM) and Multidimensional Feature Fusion Module (MFFM). STCDM model utilizes a diffusion model to accurately forecast two-dimensional satellite cloud imagery. ASLSTM extracts the features of three-dimensional meteorological elements. MFFM module integrates the two-dimensional satellite cloud imagery features with the three-dimensional meteorological element features. The two-dimensional satellite cloud imagery reflects the visible aspect of cloud layers, while the three-dimensional meteorological data, which includes cloud water and ice content correlated with altitude, mainly captures the invisible aspect of cloud layers. These two sets of information complement each other, enabling a more comprehensive capture of the three-dimensional characteristics of clouds. Satellite cloud image prediction experiment and photovoltaic power prediction experiment are carried out on STCDM and MPPM model respectively. The experimental results demonstrate that the STCDM model achieved a Structural Similarity index (SSIM) of 0.909 for predicting satellite cloud imagery within 1 h and 0.789 within 24 h. Meanwhile, the MPPM model attained a pearson Correlation coefficient (CORR) of 0.945 for predicting PV power within 1 h and 0.856 within 24 h. These findings indicate that both the STCDM and MPPM models outperform other comparative algorithms in forecasting satellite cloud imagery and PV power.

Recently, bifacial photovoltaic (PV) modules have attracted more and more interest due to their potential advantage in energy yield. Transparent polymer backsheets are crucial for protecting the bifacial modules from environmental exposure to guarantee a service lifetime of PV modules of at least 25 years. However, harsh service environments often lead to the premature degradation of polymer backsheets and the loss of their protection performance. To date, understanding on the risk of failure of transparent PV backsheet is still very limited. In this study, commercial single-layer polyethylene terephthalate (PET) samples were used as the model transparent backsheet. A sequential UV exposure-fragmentation test was then conducted to evaluate their risk of failure. Changes in its key protection performance (including oxygen and water vapor barrier properties) were characterized before and after fragmentation tests. In addition, systematic characterizations of its chemical structures, crystalline structures, and mechanical properties were conducted. Moreover, to understand the correlation between their cracking patterns and barrier properties, finite element simulation was also performed. We hope that this work can provide a scientific basis for the reliability evaluation and optimization of transparent backsheets toward more durable bifacial PV modules.

The application of conventional asphalt contributes to extremely high pavement temperature in hot season as its black color entails large solar absorption. In this study, optical responsive asphalt is proposed to control pavement temperature, which is developed by introducing temperature-sensitive TiO₂ quantum dots (TiO₂ QDs) into traditional asphalt. Temperature-sensitive TiO₂ QDs are prepared by blending thermochromic polymer and TiO₂ quantum dots with varied concentrations. Optical characterizations on temperature-sensitive TiO₂ QDs have demonstrated that peak value of solar absorption in temperature-sensitive TiO₂ QDs at 45 °C is 14.29 %–22.86 % higher than that at 15 °C; the maximum fluorescent intensity of temperature-sensitive TiO₂ QDs at 45 °C is 8.5 % higher than that at 15 °C. The results from optical characterizations on temperature-sensitive TiO₂ QDs modified asphalt show that the incorporation of temperature-sensitive TiO₂ quantum dots endows asphalt low solar reflectance at high temperature and high solar absorption at low temperature. Fluorescent intensity of modified asphalt at 45 °C is increased by 21.6 %, 10.2 % and 5.7 % than that at 15 °C for asphalt containing 5 %, 10 %, and 20 % temperature-sensitive TiO₂ QDs, respectively. Indoor solar radiation simulation tests have revealed that compared with traditional asphalt, temperature-sensitive TiO₂ QDs modified asphalt coating could yield cooling effectiveness of 6.4 °C at high temperature. Meanwhile, outdoor solar radiation test indicates TiO₂ QDs modified asphalt coating could realize warming effectiveness of 0.7 °C at low temperature. The outcomes on temperature-sensitive TiO₂ QDs modified asphalt with temperature-adaptability properties makes an advancement in functional pavement.

Solar cells offer a potential solution to the energy crisis, and perovskite solar cells are the latest frontrunner. However, low electrical conductivity of TiO₂ ETL serves as a bottleneck to its efficiency. In this study, Al-Mg co-doped anatase thin films are prepared by one-step spin coating method and then characterized to tackle this problem. XRD results show that doping leads to smaller crystallite size and decreased interplanar spacing, but increases the lattice strain and dislocation density. AFM images reveal that Al-Mg co-doping increases surface roughness. Surface morphology of the co-doped film is good, covering the whole substrate uniformly without any pinholes. XPS results ensure that the desired composition is achieved. UV–vis spectroscopy data show that optical bandgap increases with Al-Mg co-doping, leading to the highest bandgap for Ti_0.87Mg_0.1Al_0.03O_2, which also has the highest transmittance peak, reaching 90 % in the visible region. Urbach energies are also calculated to get a better estimate of the effective bandgaps. Band edge positions are calculated using Mulliken’s electronegativity, demonstrating improved band alignment due to Al-Mg co-doping. The bandgap trend is further corroborated with DFT + U simulations, which show that calculated bandgaps match the experimentally obtained optical bandgaps. Additionally, density of states reveal that Ti 3d orbital dominates the conduction band and O 2p orbital dominates the valence band, with hybridization taking place between different orbitals. Four-point probe test demonstrates that Al-Mg co-doping leads to a consistent decrease in sheet resistance of the thin film. Better band alignment and higher visible light transmittance combined with enhanced conductivity indicate that Al-Mg co-doped anatase thin film has high potential as an ETL for perovskite solar cells.

The thermodynamic performance of supercritical CO₂ (sCO₂) Brayton cycle deteriorates significantly due to the mismatch between the cold source temperature and the working fluid’s critical point. Here, we present the first study on the off-design performance of a novel supercritical CO₂ mixture Brayton cycle with floating critical points. A distillation based regulation subsystem is integrated into the power cycle to dynamically adjust the circulating composition of the binary CO₂ mixture, thereby making its critical point float with the ambient temperature and achieving good temperature matching. The off-design behavior of the system operating with the representative mixture is investigated based on an in-house code. The influence of trigger conditions of critical point regulation on energy consumption of the regulation process is investigated. When the maximum temperature difference of the design points for consecutive days is set to 3 °C, the equivalent power consumption can be limited to 2.34 × 10⁶ MJ per year, which affects the annual efficiency by less than 1 %. The results confirms that using the floating critical point method can improve the annual efficiency by 7 %-10.9 % and improve the specific output power by 6.1 %-9.4 % compared to the sCO₂ cycle, depending on the power plant locations.

Water photovoltaic (WPV) power stations have developed rapidly in recent years around the world. However, the thermal performance, power generation characteristics and the influence on water temperature and water quality of WPV power station need to be further studied. At present, there is no systematic and complete numerical method that can simulate the impact of solar panel on water environment. In this paper, a joint calculation method of WPV heat exchange model and 1-D hydrodynamic and water quality model is proposed. Taking Hebei section of the middle route of the South-to-North Water Diversion project as an example, the solar panel temperature, electrical efficiency, water temperature and water quality changes are analyzed. The results show that, compared with the static water condition, the solar panel temperature and air temperature below the panel decrease under flowing water condition. And the photoelectric efficiency is improved. After covering the WPV, the air temperature below the panel is significantly affected by the solar panel temperature. When moving from south to north along the middle route of the South-to-North Water Diversion project, the photoelectric conversion efficiency of WPV gradually increases, but module output power per square meter drops by 1.75 W/m². The short-wave radiation flux reduction factor of WPV should be less than 20 % for ensuring the stability of water quality and the large discharge will weaken the short-wave radiation flux reduction influences on water quality.

Increasing the diffusivity of transmitted light at crop canopies in agrivoltaic (AV) systems remains a desired objective. This is because diffuse light increases the uniformity of light distribution and penetrates deeper into compact crop canopies thereby enhancing the photosynthesis rate and crop yields. Current approaches in greenhouses and open horticultural systems involve the use of diffusing films, diffuse glass, and light diffusing coatings. While these methods are effective, their combination with photovoltaic (PV) modules in AV greenhouses and other AV farming practices remain relatively unknown. However, little to no work has been done to assess the light scattering properties of the existing PV module structural materials such as the glass, encapsulants and the transparent backsheet. This work therefore investigates the light scattering behaviour of c-Si PV module materials through haze and Hortiscatter measurements. 18 samples with the structural layout of glass/encapsulant/encapsulant/back cover (glass or transparent polymer backsheet), applying different commercial encapsulants, were manufactured and tested experimentally. Light in the photosynthetic spectrum was used in the optical characterization of the samples. Furthermore, the impact of UV degradation on the haziness was also tested and the uniformity of the light distribution was further assessed to obtain the Hortiscatter. The findings indicated that (i) Transparent backsheets increased the light diffusivity. (ii) UV degradation reduced the light scattering of most of the PV materials. (iii) For the haziest transparent backsheet sample, the distribution of the transmitted light increased with the incidence light angle and reduced with increasing wavelength in the visible spectrum (iv) Highest haze and Hortiscatter values of up to 80% and 84% respectively were obtained for a sample with glass/TPO/TPO/transparent backsheet layout. (v) Haze and Hortiscatter values could help in optimising the PV module bill of materials for AV applications.