Solar concentrators

A solar concentrator uses a lens or reflector to capture sunlight from a wide area and focus it onto a small area where a photovoltaic convertor device is located. Sunlight concentration may be as little as 2X or as high as 2400 X. Like utility-scale photovoltaic arrays, solar concentrators are essentially a large-capacity deployment technique.

Concentrators require much smaller quantities of semiconductor material than conventional photovoltaic arrays. As a consequence it becomes cost effective to use the most efficient material available, even if this is much more expensive than the material used in large photovoltaic arrays. With only a small area of semiconductor, most of the concentrator is made from relatively cheap and readily available materials. This means that scaling up to larger sizes is easy and economical to achieve.

There are various ways of building concentrators. These range from arrays of small cells, each with a lens focusing sunlight from a small area onto a tiny photovoltaic device, to a 10-20 m parabolic reflector collecting sunlight and concentrating it at a small central receiver where the photovoltaic convertor is situated. Common to them all is the need to track the sun in order to achieve good performance, because concentrators generally rely on the incident sunlight being perpendicular to the actual solar cell.

While concentrators have yet to gain much of a foothold terrestrially, they are attracting the attention of the space industry. Their advantage in space over conventional photovoltaic arrays is a reduced exposure to radiation damage because the sensitive photovoltaic convertor is shielded inside the device. This gives them, potentially, a much longer life.

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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