18 research outputs found
Fiber Optic Daylighting with Concentrating Solar Collectors: A State-of-the-Art Review
No full textNowadays, the development of innovative and feasible sustainable solutions able to reduce lighting costs and enhance the building’s energy efficiency is a hot topic and one of the most challenging research avenues. In this context, fiber optic daylight (FOD) systems are a growing technology, where fiber optics can be used as a waveguide to transmit sunlight into the interior of windowless spaces. This review aims to track, analyze, and discuss the application of integrated FOD systems with concentrating solar collectors and provide a clear understanding of FOD system requirements and overall performance. In view of this, a comprehensive analysis of the most recent FOD systems, along with their different applications, has been provided to ensure a complete overview of the current state of FOD systems in terms of actual technological strengths, limitations, cost-effectiveness, and future application performance. Therefore, this paper comprehensively analyzes the structure and performance of FOD systems. It highlights the recent development and nanotechnology applications of FOD systems. Additionally, this article discusses the challenges of building-integrated FOD systems and the benefits of using FOD instead of conventional grid-integrated lighting devices and systems
Numerical Investigation of Natural Light Transmission Through Fiber Optics
No full textFiber optics is a cutting-edge technology with boundless potential for transmitting natural light inside buildings. Imaging Solar concentrators are very efficient in focusing light within the approximate numerical aperture of fiber optics. The proof-of-concept of fiber optics concentration daylight systems was investigated and elaborated for only single-mode step-index fibers, and none of the previous studies had explored the full sun spectrum meticulously, the overall transmission efficiency, and the luminous output of such a system. The present research elaborates a detailed and exclusive numerical investigation of multi-mode-indexed fiber optics daylight systems. The proposed design consists of subsequent optical stages that focus light into the fiber optic cable, filter unwanted infrared wavelength radiation, and uniformly collimate visible light onto the fiber optics. The ray path and ray power intensities were traced and computed using the ray tracing technique. The obtained simulation results demonstrated an overall optical transmission efficiency of 32% along a 10 m length. The luminous efficacy of visible light transmission was evaluated based on the average illuminance levels inside buildings, indicating a substantial indoor lighting enhancement of 92 lumens/watt. The proof-of-concept was validated by building a laboratory scale of the proposed system; the tests have shown the technical feasibility of the system and the effective material integrity for practical application
Optothermal Modeling for Sustainable Design of Ultrahigh-Concentration Photovoltaic Systems
No full textThe development of ultrahigh-concentration photovoltaic (UHCPV) systems plays a pivotal role in advancing sustainable solar energy technologies. As the demand for clean energy grows, the need to align concentrated photovoltaic (CPV) system design with high-efficiency solar cell production becomes critical for maximizing energy yield while minimizing resource use. Despite some experimental efforts in UHCPV development, there remains a gap in integrating Fresnel lens-based systems with the comprehensive thermal modeling of key components in improving system sustainability and performance. To bridge this gap and promote more energy-efficient designs, a detailed numerical model was established to evaluate both the thermal and optical performance of a UHCPV system. This model contributes to the sustainable design process by enabling informed decisions on system efficiency, thermal management, and material optimization before physical prototyping. Through COMSOL Multiphysics simulations, the system was assessed under direct normal irradiance (DNI) ranging from 400 to 1000 W/m2. Optical simulations indicated a high theoretical optical efficiency of ~93% and a concentration ratio of 1361 suns, underscoring the system’s potential to deliver high solar energy conversion with minimal land and material footprint. Moreover, the integration of thermal and optical modeling ensures a holistic understanding of system behavior under varying ambient temperatures (20–50 °C) and convective cooling conditions (heat transfer coefficients between 4 and 22 W/m2.K). The results showed that critical optical components remain within safe temperature thresholds (<54 °C), while the receiver stage operates between 78.5 °C and 157.4 °C. These findings highlight the necessity of an effective cooling mechanism—not only to preserve system longevity and safety but also to maintain high conversion efficiency, thereby supporting the broader goals of sustainable and reliable solar energy generation
Structural Analysis of a Modular High-Concentration PV System Operating at ~1200 Suns
No full textThe progression of research in concentration photovoltaic systems parallels the advancement of high-efficiency multi-junction solar cells. To translate the theoretical optical framework into practical experimentation, a modular and structurally validated mechanical configuration for a high-concentration photovoltaic (HCPV) system was developed, incorporating boundary conditions and ensuring full system integration. The system incorporates a modular mechanical architecture, allowing flexible integration and interchangeability of optical components for experimental configurations. The architecture offers a high degree of mechanical flexibility, providing each optical stage with multiple linear and angular adjustment capabilities to support precision alignment. To ensure tracking precision, the system was coupled with a three-dimensional sun tracker capable of withstanding torques up to 60 Nm and supporting a combined payload of 80 kg, including counterbalance. The integration necessitated implementation of a counterbalance mechanism along with comprehensive static load analysis to ensure alignment stability and mechanical resilience. A reinforced triangular support structure, fabricated from stainless steel, was validated through simulation to maintain deformation below 0.1 mm under stress levels reaching 5 MN/m2, confirming its mechanical robustness and reliability. Windage analysis confirmed that the tracker could safely operate at 15 m/s wind speed for tilt angles of 35° (counter-clockwise) and −5° (clockwise), while operation at a 80° (counter-clockwise) tilt is safe up to 12 m/s, ensuring compliance with local environmental conditions. Overall, the validated system demonstrates structural resilience and modularity, supporting experimental deployment and future scalability
Synergistic Effect of Paraffin-Incorporated In<sub>2</sub>O<sub>3</sub>/ZnO Multifold Smart Glazing Composite for the Self-Cleaning and Energy-Saving Built Environment
No full textThe thermal performance
of window glazing requires improvement
for a sustainable built environment at an acceptable cost. The current
work demonstrates a multifold smart composite consisting of an optimized
In2O3/ZnO–polymethyl methacrylate–paraffin
composite to reduce heat exchange through the combined self-cleaning
and energy-saving envelope of the smart built environment. This work
has attempted to develop a smart composite coating that combines photosensitive
metal oxide and phase change materials and investigate their thermal
comfort performance as a glazed window. It is observed that the In2O3/ZnO (5 wt %) multifold composite film experienced
better transmittance and thermal performance compared to its other
wt % composite samples. Moreover, the multifold composite-coated glass
integrated into a prototype glazed window was further investigated
for its thermal performance, where a steady average indoor temperature
of ∼30 °C was achieved when the outside temperature reached
∼55 °C, while maintaining good visibility. Interestingly,
the transparency reached ∼86% at 60 °C and exhibited a
hydrophobic water contact angle (WCA) of ∼138°. In contrast,
a similar film exhibits ∼64% transparency at 22 °C, where
the WCA becomes moderately hydrophilic (∼68°). Temperature
dependency on transparency and wettability properties was examined
for up to 60 cycles, resulting in excellent indoor thermal comfort.
In addition, a thermal simulation study was executed for the smart
multifold glazing composite. Moreover, this study offers dynamic glazing
development options for energy saving in the smart built environment
Design and Optimization of a Solar Parabolic Dish for Steam Generation in a Blue Hydrogen Production Plant
No full textThe integration of renewable energy into industrial processes is crucial for reducing the carbon footprint of conventional hydrogen production. This work presents detailed design, optical–thermal simulation, and performance analysis of a solar parabolic dish (SPD) system for supplying high-temperature steam to a Steam Methane Reforming (SMR) plant. A 5 m diameter dish with a focal length of 3 m was designed and optimized using COMSOL Multiphysics (version 6.2) and MATLAB (version R2023a). Optical ray tracing confirmed a geometric concentration ratio of 896×, effectively focusing solar irradiation onto a helical cavity receiver. Thermal–fluid simulations demonstrated the system’s capability to superheat steam to 551 °C at a mass flow rate of 0.0051 kg/s, effectively meeting the stringent thermal requirements for SMR. The optimized SPD system, with a 5 m dish diameter and 3 m focal length, was designed to supply 10% of the total process heat (≈180 GJ/day). This contribution reduces natural gas consumption and leads to annual fuel savings of approximately 141,000 SAR (Saudi Riyal), along with a substantial reduction in CO2 emissions. These quantitative results confirm the SPD as both a technically reliable and economically attractive solution for sustainable blue hydrogen production
Optical component analysis for ultrahigh concentrated photovoltaic system (UHCPV)
No full textThis is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThis article investigates the discrepancy between the theoretical and the experimental optical characterisation results of a Fresnel Lens - silicon on glass (SOG), as a primary optical component toward UHCPV of >3000 suns design (Shanks et al., 2018). All the equations were elaborated for single- and multi-junction solar cells, emphasising the performance when the focal spot area is larger or lesser than the solar cell area. This simple prediction approach of optical characterisation has shown a strong agreement between the theoretical and experimental results of the multi-junction solar cell with a discrepancy of 2% at 7.7 W (77 suns) and 6% on the average cross a solar irradiance on the cell from 3.1 W to 7.7 W corresponding to 31 suns – 77 suns in concentration ratio. A theoretical analysis of the optical performance for a 1/4 of the system grouping three optical interfaces is performed to estimate the optical loss and its influence on the optical efficiency and optical concentration ratio.Saudi Arabia Culture Bureau in the UKNewton-Mosharafa Fun
Graphene as a pre-illumination cooling approach for a concentrator photovoltaic (CPV) system
No full textThis is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThe concentrator photovoltaic (CPV) system has a high potential in increasing the power output, propelling further the concentration ratio generating excessive heat that significantly deteriorates the solar cell efficiency and reliability. To thoroughly exploit graphene as a pre-illumination cooling technique for a solar cell, we experimentally characterized screen printed graphene coating (GC) physicochemical characterizations to observe the attenuation of light across a wide wavelength range with different GC thicknesses on a low iron-glass. The thermal and electrical characterizations were further executed to observe the performance of GC on a concentrated CPV system. Based on these comprehensive experimental characterizations, the concept of utilizing graphene as a neutral density (ND) filter for focal spot CPV system is shown to reduce the device temperature significantly by 20% and 12% for GC6.3 (6.3 μm thickness) and GC2.2 (2.2 μm thickness) in comparison with the infrared filter, respectively. It has been observed that GC6.3 increased the cell efficiency by about 12% at 8 suns compared to the base case at 400 W/m2 producing 7 suns. It has been ascertained that the introduction of graphene as the ND filter component improved the solar cell efficiency instead of just reducing the geometrical concentration ratio. Further, even the most susceptible single-junction solar cell under a concentration ratio of 20 suns with no cooling aid has shown an excellent cell efficiency. Therefore, our approach envisages its application for non-CPV and high and ultrahigh CPV system incorporated with a triple-junction solar cell eliminate the use of external heat sinks or other cooling arrangements.Saudi Arabia Culture Bureau in the UKAgri-tech CornwallIsles of Scilly projec
Optical Losses and Durability of Flawed Fresnel Lenses for Concentrated Photovoltaic Application
No full textThis is the author accepted manuscript, the final version is available from Elsevier via the DOI in this record.Recycling optical devices and materials for solar concentrator devices is a relatively
unstudied area but one which is likely to grow in importance as we progress towards an
increasingly sustainable and minimum waste environment. As such, considerations into
major optical flaws are required. Here, we have investigated the durability of a cracked
Silicon on Glass (SOG) Fresnel lens incorporated as the primary optical component in a
concentrated photovoltaic (CPV) application. Optical and electrical characterisations of
the flawed glass have been conducted to show the effect on the performance. The optical
characterisation has shown a drop of 3.2% in optical efficiency. As well, I-V and power
curves of cracked and non-cracked Fresnel lens were compared to shows a drop of 3.2%
in short circuit current (Isc) and power. The results have confirmed that the power loss is
directly related to only the area of the primary optic flawed, which has been calculated
through as a percentage of geometrical loss (a form of shadowing) which was estimated
to be 2.7% of the concentrator area. From the results, we can confirm that although the
performance has slightly declined for the significantly flawed Fresnel lens, there are no
other detrimental optical effects. The durability of such optics still needs to be tested, but
from these results, we recommend that similarly critically flawed optics can be utilised,
likely in non-demanding singular CPV units where < 5% loss is acceptable.Saudi Arabia Culture Bureau in the United KingdomNewton-Mosharafa Fund (UK-Egypt partnership
Synergistic effect of paraffin incorporated In2O3:ZnO multi-fold composite smart glazing for the self-cleaning and energy-saving built environment
No full textThis is the final version. Available on open access from the American Chemical Society via the DOI in this record. The thermal performance of window glazing requires improvement for a sustainable built environment at an acceptable cost. The current work demonstrates a multifold smart composite consisting of an optimized In2O3/ZnO–polymethyl methacrylate–paraffin composite to reduce heat exchange through the combined self-cleaning and energy-saving envelope of the smart built environment. This work has attempted to develop a smart composite coating that combines photosensitive metal oxide and phase change materials and investigate their thermal comfort performance as a glazed window. It is observed that the In2O3/ZnO (5 wt %) multifold composite film experienced better transmittance and thermal performance compared to its other wt % composite samples. Moreover, the multifold composite-coated glass integrated into a prototype glazed window was further investigated for its thermal performance, where a steady average indoor temperature of ∼30 °C was achieved when the outside temperature reached ∼55 °C, while maintaining good visibility. Interestingly, the transparency reached ∼86% at 60 °C and exhibited a hydrophobic water contact angle (WCA) of ∼138°. In contrast, a similar film exhibits ∼64% transparency at 22 °C, where the WCA becomes moderately hydrophilic (∼68°). Temperature dependency on transparency and wettability properties was examined for up to 60 cycles, resulting in excellent indoor thermal comfort. In addition, a thermal simulation study was executed for the smart multifold glazing composite. Moreover, this study offers dynamic glazing development options for energy saving in the smart built environment.Engineering and Physical Sciences Research Council (ESPRC
