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photovoltaic system

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Researchers from the Masdar Institute of Science and Technology have developed a novel device that can track and concentrate sunlight onto high-efficient solar cells, without mechanically moving to follow the sun’s path across the sky. This proof-of-concept research is the first step towards the development of a self-tracking concentrating photovoltaic (CPV) system.

“Traditional CPV systems rotate solar panels to face the sun using a mechanical tracker that is both expensive and too big to put on rooftops,” explained Masdar Institute Research Engineer Harry Apostoleris, whose Master’s thesis focused on this work.

“We are trying to accomplish this tracking through a flat system that does not move, by changing only the optical properties of the collector, not its physical orientation,” he added.

Apostoleris is lead author of a paper published on this research earlier this month in the journal Nature Energy with his supervisor, Dr. Matteo Chiesa, Associate Professor of Mechanical and Materials Science Engineering, Masdar Institute, and Dr. Marco Stefancich, Researcher at the National Research Center in Parma, Italy. Their research was awarded an MIT Deshpande Center research grant for its innovative potential.

The team’s proposed sun-tracking system acts like a box – made of an opaque, waxy material made of a silicone and paraffin composite – that employs an optical “hole” on its surface to track the sun’s path throughout the day. As the sun’s infrared and visible light enters the hole on the box’s surface, the reflected rays are blocked when they try to escape and are utilized by high-efficiency PV cells.

The hole is created by focusing sunlight onto a single spot, which becomes transparent when hit with concentrated light, allowing the sunlight in. The box’s material is opaque when cold and transparent when hot. Thus, by focusing light onto the material, a small transparent region is created.

A lens is placed in front of the box, concentrating and directing sunlight onto a small area of the transparency-switching material, creating the optical ‘hole’ or transparent area. As the sun moves, causing the location of the focal spot to vary, the hole moves so that light can continually enter the device.

Traditional CPV systems reach high light-to-electricity conversion efficiencies – 30% or more – by concentrating direct sunlight onto multi-junction solar cells. These bulky systems track the sun’s path throughout the day with expensive and heavy mechanical systems that rotate as the sun moves.

Though, according to a report by IHS Technology, CPV installations have increased by 37% this year, their high costs and weight make them suitable only for utility-scale PV in regions with very clear skies, rendering them essentially absent from the fast-growing distributed PV market.

The main form of distributed PV, rooftop solar panels, are usually made of silicon or thin-film semiconductor cells with module efficiencies between 15-20% and are dominating the solar market. In the United States, more rooftop solar panels were installed in the first quarter of this year than natural gas power plants.

Because CPV efficiencies are much higher than flat solar panels commonly used for distributed applications, there is growing interest to make CPV systems accessible to the distributed market.

“The only thing holding CPV back from widespread residential use is its large size and high upfront costs,” explained Dr. Chiesa. “Our CPV system is compact, stationary and made of low-cost materials – which are key requirements for distributed PVs.”

Dr. Chiesa and Apostoleris have filed a patent for their Proof-of-Concept (PoC) sun-tracking system, which is the first step towards commercialization of the technology.

The team’s development of a next-generation CPV technology reflects Masdar Institute’s support of cutting-edge research that seeks to find sustainable, clean energy alternatives that are price competitive with conventional, fossil-fuel sources.

 

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Bad Staffelstein, January 20, 2016 – IBC SOLAR AG, one of the world’s leading photovoltaic (PV) system service providers, is giving farmers the opportunity to switch to a non-toxic, low-cost and reliable water supply: expensive and high-maintenance diesel generators can now be replaced with a PV system linked to the IBC PumpController. This system can be connected via a Siemens frequency converter to existing water pumps. Existing irrigation systems can therefore easily be converted to use a significantly more efficient and lower-cost power supply.

Both the existing pumps and the entire irrigation infrastructure are conserved during the conversion, and only the diesel generator is replaced by a PV system. The IBC PumpController system solution combined with a PV system is structured around concepts of standardisation, modularisation and the global quality promise of IBC SOLAR.

Only standard components are used by IBC SOLAR as they are easy to maintain and replace. The Sinamics S120 frequency converter including Maximum Power Point Tracking (MPPT) from Siemens installed in the IBC PumpController ensures that the maximum output can be taken from the photovoltaic generator.

 Replacing expensive diesel with reliable solar power

The benefits of the solar system solution will be immediately noticeable to farmers who are converting to a solar power supply. Diesel fuel is expensive to purchase and poses risks during transportation and storage. Diesel is also not cost effective as a fuel source because the cost of importing is supported by government subsidies in many countries. Solar energy, on the other hand, is a reliable and low-cost form of power supply in the agricultural sector, especially in areas where demand for water is high.

Furthermore, energy supply and water demand fit together perfectly. Water is typically in need after sunny PumpController-Namibia_bajadays, thus right after water tanks have been filled with the aid of solar power. Once installed, the PV system also only incur minimal maintenance costs.

 Pilot plants with cost recovery within 3 years

A pilot plant on a farm in Namibia has been showing the practical functions of the system solution since June 2015. An IBC SOLAR PV system with a maximum output of 17.7 kWp and an IBC PumpController has permanently replaced an 11 kVA diesel generator. This conversion has made possible the environmentally-friendly and, above all, reliable drip irrigation of arable land, while saving 30 litres of diesel per day. “The investment in the solar-powered pump solution will pay off within 3 years,” explains Dieter Miener, Technical Applications Engineer at IBC SOLAR.

IBC SOLAR will include 10 performance classes ranging between 3 and 90 kW in its portfolio. Due to the positive experiences gained in Namibia and further countries, IBC SOLAR is now offering the system solution in the target markets of Africa and Latin America through its Premium Partners. In addition to its use in agricultural fields, the solution can also be implemented in the fish farming, wastewater treatment or tourism sectors.

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