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The world’s oldest, and still functional, Concentrator Photovoltaic (CPV) power plant originally rated at 350 kW, and is situated 50 km from Riyadh, Saudi Arabia. There are ongoing efforts to retrofit the modules with new secondary optics and triple-junction cell devices. The paper characterizes the initial optical train, whose design is non-conventional in its use of a two-area primary Fresnel lens. The first generation of a retrofit receiver package is described. Challenges beyond the optical design are encountered, including tracking and structural mechanics. [ABSTRACT FROM AUTHOR]

King Abdulaziz City for Science and Technology (KACST) in collaboration with IBM has developed the first manually manufactured concentrator photovoltaic (CPV) modules. A single CPV module is rated at 120 W at nominal operating test condition (NOTC) of 1000 W/m2 direct normal insolation (DNI) and 25 °C ambient temperature. Two trackers are installed and operated in the solar village outside Riyadh and one located in the eastern coastal city of Alkhafji. Figure 1 shows the trackers in Solar Village and Alkhafji. Valuable lessons were learned after three years of operating the systems on sites with different environmental characteristics. A production process flaw that caused cell material weakening and falling of light pipes from the cell have caused huge output degradation. Other factors that improved module performance are modification of production methods, integrating and replacing new parts. The Fresnel lens was replaced with a higher transmission efficiency lens of the same make as the former. Focal length of the new lens was determined and a new aluminum casing with different dimension was produced. This paper discusses in details the manufacturing process of two modules. The modules are essentially the same except for the cell used in each one. Both modules were manufactured using the modified process. New parts have been incorporated. The modules were then installed in the solar village. Data are being collected at a time interval of 10 minutes. I-V curve tests are also being acquired at different environmental conditions. Analysis and comparisons of these modules with one old module shall be presented. [ABSTRACT FROM AUTHOR]

The three year KACST/IBM collaboration in solar technology research led to the design and development of a 10kW CPV system. The system is comprised of 81 PV modules, inverters and a tracking system and is grid connected. A primary and secondary optics were employed to reach 1600x concentration on multijunction solar cells. Two CPV trackers were installed in the city of Riyadh and one in the eastern coastal city of Al Khafji. These two areas differ in climatic conditions. Riyadh is mostly dry and very often hit by very strong sand storms while Al Khafji is very humid with sand storms. Very fine dusts and dirt carried by the storms hits the surface of the primary optics, Fresnel lens, of the system. In Riyadh, the particles stick to the lenses but accumulation in the surface is not much since it is blown away by wind. However, the humid condition of the coastal areas wets the dusts and makes it sticky, cumulating more dusts and dirt. This paper discusses in details the parts of the 10kW CPV system. It presents a comprehensive analysis of the system's performance since the time they were installed and operated. CPV systems are operated with the least number of personnel and supervision. However, dust and dirt lessens the amount of sunlight passing through the primary optics. It requires periodic cleaning of the Fresnel lens. Different methods of cleaning were tried to identify the efficient way to clean the system that results to a higher power generation. Corrections and modifications of the system to further increase power production are presented. [ABSTRACT FROM AUTHOR]

This paper discusses the development and deployment of an ultra-high concentrating PV module that utilizes concentration above 1400X on multijunction solar cells. The development process included the selection of cell assemblies, primary and secondary optics, and focal distance. The systems were deployed in Saudi Arabia inside the Solar Village near Riyadh and in Khafji near the border of Saudi and Kuwait, following the deployment of first prototype in Yorktown, NY. Data from operation in those areas are shown here, and next steps of optimizing the module performance are discussed. [ABSTRACT FROM AUTHOR]

Practical multi receiver ultra high (1000+ Suns) concentration photovoltaic (UHCPV) systems experience large radiation, thermal and electrical loads in addition to large power density transients under routine operation. This report is a summary of the issues involved in determining the practical limits to concentration. How high is too high? Explorations into UHCPV have both theoretical and experimental aspects. Understanding the theoretical device physics and circuit limitations is often essential to determining which experiments to do and in interpreting results. On the experimental side the work can be divided into two fields depending on the type of light source. The first is artificial or simulated sources and the second is working in the field with direct solar irradiation. Both fields have advantages and disadvantages. Direct solar radiation was selected for the current experiments due to the low cost and ability to produce ultra high concentrations (4000+) over relatively large areas (25+ mm2). Several experimental examples from these direct solar measurements shed light on some of the basic theories of how concentrated light affects the performance of multi junction photovoltaic cells. Out of these examples and theoretical foundations we conclude that for practical devices the first order constraint to optimum efficiency at ultra high concentrations is the series resistance. We also present a simple model based on published data and our results that can be used to predict the total system series resistance needed to optimize a system for a particular concentration. [ABSTRACT FROM PUBLISHER]