Taher Maatallah

Air gap membrane desalination (AGMD) is an emerging energy-efficient desalination technology, but its freshwater production rate is limited by the high resistance of mass and heat transfer across the air gap. To overcome this limitation in AGMD, a passive finned design is used to effectively increase the total available surface area for condensation. Three types of fins—pin fins, trapezoidal fins, and rectangular fins—were developed and investigated via the COMSOL Multiphysics coupled model and were then prototyped. The results from the experimental test were consistent with the coupled model analysis and proved the rectangular fin to be the best option. The rectangular fin attained a flux of 12.04 kg m⁻² h⁻¹, while the flat-plate fin had a flux of 2.70 kg m⁻² h⁻¹. In addition, the rectangular fin had continuous channels to allow for better water drainage and therefore was able to reduce the film resistance. The passive fin increases freshwater production and reduces specific energy consumption (SEC) per unit volume of freshwater produced. Ultimately, the findings demonstrate that finned condensation plates offer a scalable and thermodynamically viable approach to optimizing AGMD systems without requiring complex active components or additional energy input.

Green hydrogen (H₂) production is a pivotal element of Saudi Arabia’s Vision 2030. This study presents a comprehensive feasibility assessment of a high-efficiency H₂ production system integrating a photovoltaic (PV) array and a high-concentration photovoltaic (HCPV) system with a Proton Exchange Membrane (PEM) electrolyzer, specifically designed for harsh climatic conditions. To evaluate the system’s viability, a comprehensive simulation model was developed based on rigorously validated mathematical formulations. First, the performance of the PEM electrolyzer and the effectiveness of the cooling system were modeled using established electrochemical and thermal correlations derived from the peer-reviewed literature. Second, this model was applied to evaluate the system’s long-term energy yield and economic performance. Key economic metrics, including the levelized cost of H₂ (LCOH) and discounted payback period (DPBP), were calculated based on local solar irradiance data, followed by a sensitivity analysis to assess the economic robustness under varying market conditions. The results demonstrate that the proposed configuration is not only technically feasible—maintaining high efficiency despite harsh environmental conditions—but also economically viable, offering a competitive LCOH and attractive DPBP that align with the strategic objectives of Saudi Vision 2030.

Improving the efficiency of electric water heating systems is essential for reducing energy use and supporting sustainable energy utilization. This study presents the development and optimization of an ultra-efficient electric water heater incorporating graphene-enhanced thermal elements to improve heat-transfer performance and overall system efficiency. The proposed design utilizes graphene-based extended surfaces to enhance heat spreading and increase the effective heat-transfer area of the heating element. A combined numerical analysis and three-dimensional transient simulation approach was employed to evaluate the thermal behavior of the system and quantify the performance improvements achieved through design optimization. The results demonstrate significant enhancement in heating performance compared with conventional heater configuration. Under identical operating conditions, the optimized heater achieved up to a 68.4% reduction in the modeled heater-side thermal load, while maintaining the required heating performance. Additionally, the effective heat-transfer rate increased by approximately 108%, primarily due to a 102% increase in effective heat-transfer area resulting from geometric refinement of the heating surfaces. The incorporation of graphene improved heat distribution within the heating element and facilitated more efficient heat transfer to the surrounding water. These improvements lead to enhanced thermal utilization, reduced peak heating demand, and improved compatibility with renewable energy systems, highlighting the strong potential of graphene-based thermal enhancements for next-generation high-efficiency electric water heating technologies.

High-concentration photovoltaic (HCPV) systems present significant thermal management challenges due to the intense heat fluxes generated under concentrated solar irradiation, especially in arid environments. Effective heat dissipation is critical to prevent performance degradation and structural failure. This study investigates the thermal performance and design optimization of an enhanced HCPV module, integrating numerical, analytical, and experimental methods. A coupled optical-thermal-electrical model was developed to simulate ray tracing, heat transfer, and temperature-dependent electrical behaviour, with predictions validated under real-world desert conditions. Compared to a baseline commercial module operating at 106°C, the optimized design achieved a peak temperature reduction of 16°C, lowering the cell temperature to 90∘C under a concentration ratio of 961× and direct normal irradiance (DNI) of 950 W/m2. The total thermal resistance was reduced from 0.25 to 0.15 K/W (a 40% improvement), and the electrical efficiency increased from 37.5% to 38.6%, representing a relative gain of approximately 3.1%. The system consistently maintained a fill factor exceeding 78%, underscoring stable performance under high thermal load. These findings demonstrate that targeted thermal design, informed by integrated modeling, is essential for unlocking the reliability and efficiency of high-flux solar energy systems.

The transition to low-carbon energy systems necessitates innovative design strategies for decarbonizing hydrogen production, particularly in industrial-scale applications where steam methane reforming (SMR) remains predominant. This study proposes a novel, integrated process design for blue hydrogen production that addresses both energy and environmental sustainability through process intensification and resource valorization. A hybrid system was developed that combines solar thermal energy input with the catalytic potential of industrial waste, specifically, red mud, a byproduct of alumina refining. A solar parabolic dish (SPD) was engineered to contribute 10% of the heat demand, generating superheated steam at 477 °C. This work serves as a proof-of-concept, demonstrating the technical viability of integration at a bench scale. In parallel, red mud was characterized, thermochemically activated, and formulated into a low-cost catalyst for the SMR process. The integrated system includes solar-assisted steam generation, red mud-based catalytic reforming, CO₂ capture using methyl diethanolamine (MDEA), and hydrogen purification via pressure swing adsorption (PSA). The full process was modeled and optimized using ASPEN Plus, ASPEN Adsorption, and COMSOL Multiphysics^® Under optimal conditions (900 °C, 25 bar, steam-to-carbon ratio of 3), the system produced 1070 kg/h of hydrogen, achieving 95% CO₂ capture efficiency and 99.99% hydrogen purity. Techno-economic analysis revealed the red mud-derived catalyst costs 3.89 SAR/g (1.04 USD/g), a 77% cost reduction compared to conventional Ni-based catalysts. The integration of solar thermal energy, while offering modest direct economic savings of approximately 9500 SAR (2530 USD) annually, primarily demonstrates the technical feasibility of renewable heat integration for reducing the carbon intensity of hydrogen production.

The 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.

This study presents the development and validation of a high-efficiency optical interface designed for ultra-high-concentration photovoltaic (UHCPV) systems, with a focus on enabling clean and sustainable solar energy conversion. A Fresnel lens serves as the primary optical concentrator in a novel system architecture that integrates advanced optical design with system-level thermal management. The proposed modeling framework combines detailed 3D ray tracing with coupled thermal simulations to accurately predict key performance metrics, including optical concentration ratios, thermal loads, and component temperature distributions. Validation against theoretical and experimental benchmarks demonstrates high predictive accuracies within 1% for optical efficiency and 2.18% for thermal performance. The results identify critical thermal thresholds for long-term operational stability, such as limiting mirror temperatures to below 52 °C and photovoltaic cell temperatures to below 130 °C. The model achieves up to 89.08% optical efficiency, with concentration ratios ranging from 240 to 600 suns and corresponding focal spot temperatures between 37.2 °C and 61.7 °C. Experimental benchmarking confirmed reliable performance, with the measured results closely matching the simulations. These findings highlight the originality of the coupled optical–thermal approach and its applicability to concentrated photovoltaic design and deployment. This integrated design and analysis approach supports the development of scalable, clean photovoltaic technologies and provides actionable insights for real-world deployment of UHCPV systems with minimal environmental impact.

The 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.

The 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.