CPV solar farm

ZenithSolar, an Israeli start-up company, has recently launched its first 'solar farm' near Tel Aviv, based on concentrated photovoltaic (CPV) systems developed by Prof David Faiman of Ben-Gurion University of the Negev (BGU).

Faiman, who is chairman of the Department of Solar Energy and Environmental Physics at BGU's Jacob Blaustein Institutes for Desert Research, believes that the system will harvest more than 70 per cent of incoming solar energy (as compared to industry norms of between 10 per cent and 40 per cent).

The concept of CPV systems is to use low-cost optics to increase the light incident onto high-efficiency semiconductor solar cells, thus reducing overall cost of the system while increasing energy output.

The ZenithSolar optical dish is based on a patented design, using multiple simple flat mirrors mounted on a plastic surface. The moulded plastic surface, divided into four quadrants, is fixed onto a rigid, high-precision metal frame assembled onto an azimuth elevation solar tracking system.

The concentrated solar radiation is reflected from each individual mirror onto an array of solar cells. ZenithSolar uses field-proven high-efficiency multi-junction III-V solar cells for the job.

In conventional CPV systems, the excess heat generated in the solar cell needs to be removed to avoid damaging the cell and to maintain high efficiency of electricity conversion.

By contrast, ZenithSolar uses the heat generated at the solar-cell receiver to provide usable hot-water heating, improving overall solar power conversion efficiency.

'By concentrating solar energy to a level 1,000 times more intense than natural sunlight and taking advantage of the higher efficiencies at which solar cells operate under these conditions, only minute amounts of expensive PV material are necessary to produce large amounts of power,' said Faiman.