Solar Energy最新文献

The combination of perovskite and chalcogenide solar cells allows for the monolithic fabrication of all-thin-film tandem with compositional tunability, facilitating optimal band gap alignment for an efficient absorption of the sunlight spectrum, while empowering flexible photovoltaic applications. However, this combination is yet to reach the levels of efficiency and production scalability seen in perovskite/silicon tandems, mostly due to the challenging fabrication of perovskite cells on top of the irregular chalcogenide cell surface. Herein, we propose to enhance the scalability of the technology by developing the ultrasonic spray coating of perovskite on top of Cu(In,Ga)S(Se) (CIGS) cells for the fabrication of monolithic tandem devices. The capability of the technique to deposit conformal perovskite coatings, aligned with interlayer optimization, results in the successful integration of perovskite and chalcogenide cells. The resulting monolithic tandem devices exhibit efficiencies close to 20%, a significant improvement on the efficiency of the single junction perovskite and CIGS reference cells. These results offer a promising pathway towards the upscaling of perovskite/CIGS device fabrication.

Conventional greenhouses, with their high transmittance for solar irradiation and conductive nature, result in significant heat transfer to the interior. While this feature is desirable in cold regions, it poses a challenge in hot arid areas, causing excessive heat and an unsuitable rise in the internal greenhouse temperature for crop growth. Conventional passive cooling methods prove insufficient, in addition, solely active cooling is both energy-intensive and environmentally harmful, making it economically unfeasible under certain conditions. In this research, a novel greenhouse design optimized for hot arid regions is proposed, incorporating several cost-effective and innovative techniques: (1) a fully sunken greenhouse, (2) a fully shaded roof with openings for diffuser lenses, (3) a thermally insulated roof, and (4) a closed-loop horizontal earth-to-air heat exchanger. Computational modeling involved developing a ray-tracing model and a heat transfer model for the proposed greenhouse. The results demonstrate that the proposed greenhouse achieves sufficient and well-distributed solar irradiation for plant growth. Also, it shows a remarkable (85.6%) reduction in cooling load during the hot season (April to October) compared to a conventional greenhouse. Furthermore, economic assessment results indicate a 67.8% reduction in the lifetime cost of greenhouse cooling compared to a conventional design.

In recent years, the urgency for harnessing solar energy for water desalination has grown significantly, driven by the escalating costs and the increasing scarcity of clean water sources. Numerous research efforts were dedicated to enhance the productivity of solar still, including the thermal energy storage materials, solar concentrators, nanofluid, and more. The main objective of this research is to improve the solar still performance by using wastes of workshops and factories so, their actual cost can be assumed to be zero. The experimental setup placed at faculty of Engineering Suez Canal University. Two solar still were included: one representing the conventional and the second one is modified with internal reflectors and woven wire mesh. The performance of the stills was assessed under identical climate conditions, considering water depths of 1, 2, 3 and 4 cm using both fresh and saline water with Total dissolved Solids of 18,562 and 35643 ppm. The obtained results indicated that the incorporation of internal reflectors and woven wire mesh led to a notable percentage increase in daily thermal efficiency and accumulative productivity ranged from 42.49 % to 45.04 % and from 43.0 % to 46.8 % respectively. The economic analysis demonstrated that the cost per liter for conventional and modified solar still was about 0.0018 and 0.0011$ per liter per m² respectively. This study’s findings suggested that the integration of internal reflectors and woven wire mesh into solar stills to obtain high productivity potable water with low cost. These results align with and reinforce previous publications in this field, highlighting the potential of this approach for addressing the pressing challenges of affordable and efficient water desalination.

Building-Integrated Photovoltaic (BIPV) systems usually operate under elevated temperatures and are under frequent shading in comparison to standard or ground installed PV systems. These operating conditions might positively or negatively influence the performance and reliability of BIPV systems components. This study introduces a comprehensive simulation framework designed to model and assess the performance and reliability of BIPV systems. The framework incorporates sub-models for buildings, energy yield, and PV module/inverter reliability, some of which are validated using experimental data from a BIPV demonstrator. Initially, we applied the framework to demonstrate the critical role of precisely estimating the micro-climate surrounding the BIPV system. This inclusion in the electrical/energy yield model, as opposed to relying solely on ambient climate conditions, significantly enhances modeling accuracy. Furthermore, the framework is employed to simulate the reliability implications of BIPV systems installed with and without ventilation. Our analysis reveals that a properly installed BIPV system with ventilation surpasses the 25-year module warranty in all studied climate zones. Conversely, systems without ventilation exhibit a substantial reduction in module lifetime, particularly in hot and dry, and hot and humid climates. Lastly, we employed the framework to assess the impact of shading on PV module reliability. While shaded BIPV systems demonstrated an improvement in module lifetime due to reduced climatic stressors, the gains were insufficient to offset energy losses from shading effects. Our proposed framework offers versatility for diverse “what if” simulations, enabling the evaluation of performance and reliability aspects of BIPV systems crucial for research and BIPV project bankability.

The paper summarizes a comprehensive analysis to determine the energy and cost benefits of static and dynamic photovoltaic (PV)-integrated shading devices when applied to windows of office spaces located in different climate zones across Australia. The evaluated dynamic shading systems consist of rotating overhangs placed above the windows and operated to minimize the annual energy demands of office spaces. For the first time, the study determines through optimization-based controls the best angle settings for the rotating overhangs on hourly, daily, or monthly basis to minimize the energy consumption of office spaces in Australia. The analysis results indicate that both optimally designed static and optimally operated dynamic PV-integrated overhangs have substantial potential to reduce the annual energy needs of office spaces for all Australian climates with annual energy savings ranging from 45% to over 100% depending on the building orientation, window size, glazing type, and overhang depth. This high energy benefits are attributed to the multi-function capability of the PV-integrated shading systems to minimize cooling and space thermal loads while maximizing on-site electricity generation. Unlike the case of static shading devices, it is found that dynamic PV-integrated overhangs allow office spaces to reach net-zero energy operation for certain climate zones in Australia.

Research on wind-induced vibration of large-span flexible photovoltaic(PV) array only give wind-induced response analysis and vibration reduction measures, but ignore morphological evolution laws among arrays. In this study, an aeroelastic model of 3-span 5-row suspension cable flexible PV array was designed with considerations to similarity ratio relationship of a strict wind tunnel test. Synchronous full-array aeroelastic wind tunnel tests of vibration under different wind direction angles and wind speed were carried out. The responsible characteristics of the structural system were analyzed systematically by using variation modal decomposition. Results demonstrated that strong vibrations were observed in the single row of PV when the wind speed was above a critical value. The support designed between PV array can restrain the strong wind-induced vibration. The wind-induced vibration degrees of each row of PV array are different, but the laws are basically consistent. The first row in the direction of the incoming flow vibrates at a low frequency. The wind-induced vibration of PV panel is mainly random buffeting, the farther away from the wind field, the more obvious the torsion. The vibration energy of vertical displacement of the PV array changes from low-order mode to high-order mode with the increase of row number. The energy dissipation phenomena of high-frequency intervals at the fifth downwind row are more obvious.

Thermochromic windows based on vanadium dioxide (VO₂) are widely used in architectural windows due to its reversible phase change process. However, traditional VO₂ windows only manage solar radiative transmittance and their emittance variation trend in the mid-infrared contradicts realistic requirements, which seriously hinders the further development of thermochromic windows. To address this issue, a VO₂ full-spectrum smart window based on theoretical calculations is proposed for adaptive adjustment of solar spectral transmittance and thermal emittance. We cleverly utilize a thin Ag layer to construct a Fabry-Perot (FP) resonant cavity with the VO₂ layer to achieve forward modulation of the emittance in the atmospheric window. Notably, the smart window has 83.8 % emittance modulated ability, which enables effective control of radiative cooling and has greatly exceeded the reported performance of the smart windows while maintaining 72.8 % high visible transparency. Energy consumption analysis indicates that the smart window has high energy-saving potential worldwide, achieving over 60 MJ/m² energy-saving effect. This simple and easy-to-manufacture smart window expands the research scope of windows and broadens application prospects in thermal management, infrared camouflage, and building energy conservation.

With the increasing adoption of mountainous photovoltaic installations, pre-stressed flexible cable-supported photovoltaic (PV) systems (FCSPSs) are becoming increasingly popular in large-scale solar power plants due to their evident adaptability to sloping terrain. The wind-induced deformation of FCSPSs significantly influences the wind field. In this study, a two-way fluid–structure interaction (FSI) analysis is conducted to assess the wind-induced vibration response of FCSPSs at various panel tilt angles. Firstly, the analysis approach for wind-induced vibration coefficients of FCSPSs is established, which involves model equivalency, coefficient definitions, model creation, and grid and solution settings. Secondly, the modal analysis is then conducted on FCSPSs at various panel tilt angles. Subsequently, the transient response of the PV structure and the variations in the wind field are evaluated by adjusting the panel tilt angles. Finally, a quantitative analysis is performed to investigate the influence of panel tilt angles on the support reaction and displacement wind-induced vibration coefficients of FCSPSs. The results indicate that the tilt angle has a certain impact on wind-induced vibration coefficients (reaction force, displacement). The effect of the tilt angle on the internal force wind-induced vibration coefficient is more pronounced. However, the variation in displacement due to wind-induced vibrations is significantly greater than the variation in internal force. Meanwhile, the displacement wind-induced vibration coefficient and the support reaction wind-induced vibration coefficient should be considered separately for different tilt angles.

Utilizing hole-transporting materials (HTMs) to extract and transport holes from perovskite materials to the electrode remains essential in most perovskite solar cell (PSC) architectures. Developing cost-effective and efficient HTMs is essential for advancing PSC technology. We have synthesized a novel HTM, TPA-IDT-TPA, which has an extended fused ring as the core moiety called indacenodithiophene (IDT) and p-methoxy triphenylamine (p-mTPA) as terminal groups. TPA-IDT-TPA exhibits appropriate frontier molecular orbital (FMO) energy levels that match perovskite materials. Density functional theory (DFT) simulations were performed to comprehend the electronic, excited-state, and charge transport properties. The DFT results indicate that the extended π-conjugation, rigidity, and the central core ring of the HTM enhanced the π-π stacking, contributing to efficient charge transport. The PSC constructed with TPA-IDT-TPA achieves a device efficiency of 8.34%, with high values of J_SC and V_OC, which can be further enhanced through molecular optimization.

The thermal characterization of a micro-pin solar thermal receiver (MSTR) for supercritical carbon dioxide (sCO₂) gaseous working fluid is presented. In a companion paper of this two-part study [1], the design and fabrication methodologies employed in the development of the MSTR were presented. As described in Fronk et al. [1], the MSTR is formed by a microlamination process with brazed headers to form multiple unit cell flow paths with fluid inlet/outlet ports. In this part of the study, on-sun tests to estimate the thermo-fluidic performance of the MSTRs using a parabolic dish concentrator are described for a 15 cm × 15 cm design with 6 unit cells. The MSTR is installed in a closed-loop sCO₂ test facility coupled to a seven-meter diameter parabolic dish. On-sun tests were performed at a receiver inlet pressure of up to 15.5 MPa and a receiver inlet temperature ranging between 31 to 398 °C. Receiver thermal efficiencies were calculated using an indirect estimation of the absorbed flux, by summing the convective and radiative losses and absorbed energy to the fluid. Thermal efficiency greater than 0.98 were obtained for estimated incident heat flux of 34–40 W/cm² at average surface temperatures ranging from 113 to 332 °C and peak surface temperatures of up to 550 °C. A sensitivity analysis, performed on the convective and radiative losses, indicates the lower limit of efficiency to be within 1.5 % of the estimated value. After a few hours of testing, the receiver failed due to an internal flow blockage that led to overheating. Optical and microstructure analysis is performed on the 15 cm × 15 cm and a failed 8 cm × 8 cm MSTR from prior work to identify possible reasons for failure.