مجال التميز | تميز دراسي وبحثي |
البحوث المنشورة |
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البحث (1): | |
عنوان البحث: |
Integration of concentrated multi-junction solar cells with small-scale organic rankine cycle |
رابط إلى البحث: |
https://www.sciencedirect.com/science/article/abs/pii/S0196890421004118 |
تاريخ النشر: |
07/05/2021 |
موجز عن البحث: |
In this paper, concentrated photovoltaic system using multiple (four) multi-junction solar cells with a refractive system for a single point focus Fresnel lens was developed to achieve high performance in terms of optical efficiency, uniformity (Peak average ratio value) and compactness. Geometric concentration ratio, F-number, focal length and height of homogenizer were investigated showing that at Geometric concentration ratio of 400×, F-number of 1.12, focal length of 632.5 mm and height of homogenizer of 50 mm, the concentrated photovoltaic achieves an optical efficiency and Peak average ratio value of 79.6% and 1.52 respectively. Active cooling was simulated in order to ensure effective operation of the multi-junction solar cells (operating temperature < 110 °C) and to investigate the potential of exploiting the heat generated in the cells to operate an Organic Rankine Cycle to maximize the overall solar energy conversion efficiency. An Organic Rankine Cycle system with a target 1 kW power output is studied at different operating conditions and working fluid in order to be integrated with the Concentrated Photovoltaic Thermal system. Various configurations for integrating the Concentrated Photovoltaic Thermal units with the Organic Rankine Cycle working at various operating conditions and working fluids were investigated. Results showed that the integrated system with surface area of 16.8 m2, Organic Rankine Cycle system using R245fa can produce 6.17 kW of electricity with overall energy conversion efficiency of 46.57%. The developed system has the potential to provide the required electricity for buildings in Saudi Arabia which enjoys abundant solar radiation. |
البحث (2): | |
عنوان البحث: |
Optical Performance of Single Point-Focus Fresnel Lens Concentrator System for Multiple Multi-Junction Solar Cells—A Numerical Study |
رابط إلى البحث: | |
تاريخ النشر: |
16 /07/2021 |
موجز عن البحث: |
This paper investigates the potential of a new integrated solar concentrated photovoltaic (CPV) system that uses a solo point focus Fresnel lens for multiple multi-junction solar cells (MJSCs). The proposed system comprises of an FL concentrator as the primary optical element, a multi-leg homogeniser as the secondary optical element (SOE), a plano-concave lens, and four MJSCs. A three-dimensional model of this system was developed using the ray tracing method to predict the influence of aperture width, height, and position with respect to MJSCs of different reflective and refractive SOE on the overall optical efficiency of the system and the irradiance uniformity achieved on the MJSCs’ surfaces. The results show that the refractive homogeniser using N-BK7 glass can achieve higher optical efficiency (79%) compared to the reflective homogeniser (57.5%). In addition, the peak to average ratio of illumination at MJSCs for the reflective homogeniser ranges from 1.07 to 1.14, while for the refractive homogeniser, it ranges from 1.06 to 1.34, causing minimum effects on the electrical performance of the MJSCs. The novelty of this paper is the development of a high concentration CPV system that integrates multiple MJSCs with a uniform distribution of rays, unlike the conventional CPV systems that utilise a single concentrator onto a single MJSC. The optical efficiency of the CPV system was also examined using both the types of homogeniser (reflective and refractive). |
المؤتمرات العلمية |
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المؤتمر (1): | |
عنوان المؤتمر: |
11th International Conference on Applied Energy ICAE2019 |
تاريخ الإنعقاد: |
12-15/08/2019 |
مكان الإنعقاد: |
Västerås, Sweden |
طبيعة المشاركة: |
Oral presentation |
عنوان المشاركة: |
Thermal Modelling of Multi-Junction Solar Cells Assembly under Fresnel-Based Concentrator Photovoltaic/Thermal System |
ملخص المشاركة: |
High solar irradiance concentration on multi-junction (MJ) solar cells leads to extremely high cell temperature, which significantly reduces cell efficiency and can lead to cell damage. Therefore, heat dissipation via cooling techniques is essential for photovoltaic solar cells under high concentration. This work develops a 3D thermal model for an assembly of four MJ solar cells with a Fresnel-based HCPV/T system and investigates the capability of active cooling to maintain a maximum solar cell surface temperature under the operating limit (i.e. 80°C). Solar cells temperatures are predicted for different concentration ratios (CRs) and inlet water velocities, varying between 200X–1000X and 0.01–0.4 m/s, respectively. At a CR of 1000X and a water velocity of 0.3 m/s, a maximum cell temperature of 79.2°C can be achieved, which is below the maximum operating temperature. Furthermore, the outlet water average temperature for multiple concentrator photovoltaic (CPV) assemblies were performed. The results showed that the solar cells’ temperatures decreased with increased inlet water velocity, and sufficient temperature uniformity was achieved by active water cooling. In addition, the outlet water’s average temperature increased considerably with the number of CPV assemblies. It was found that with four CPV assemblies using a moderate inlet water velocity of 0.01 m/s, the average outlet water temperature rose from input temperature i.e. 25°C to 44°C and 62°C for a CR of 300X and 600X, respectively. |
الرابط: |
ياسر علي سليمان العمري
دكتوراه
هندسة
University of Birmingham