Tubular solar - the shape of things to come? | The American Ceramic Society

Tubular solar – the shape of things to come?

Cylindrical solar tubes from Solyndra.

Cylindrical solar tubes from Solyndra.

Business is beginning to take shape at Solyndra, and the shape it’s taking is tubular. The Fremont, Calif.-based solar power manufacturer began selling its novel cylindrical-shaped solar tubes in July ’08 and, according to CEO Chris Gronet, the firm already has racked up $1.2 billion in contracted orders. The differences between Solyndra’s solar tubes and conventional solar panels are many. The obvious difference is their shape. Unlike conventional solar flat panels, a single Solyndra “panel” is comprised of 40 glass cylinders placed horizontally side-by-side. Their tubular shape allows each cylinder to collect sunlight from any angle, the company says.

By painting a roof white, the firm even enables cylinders to capture reflected sunlight from their “down” side. Differences also occur in installation. Traditional solar flat panels must be precisely angled with devices that add cost and time, a Solyndra press release explains. It also claims exact spacing must be provided between panels so they don’t obstruct each other’s performance, and they must be anchored by ballast or “rooftop penetration” to meet wind-loading requirements. In contrast, Solyndra’s solar tubes can be laid beside each other in straight lines across a roof. Angling and extra spacing isn’t necessary and, because the wind blows around and through Solyndra panels, the need for rooftop anchoring is also reduced.

All this adds up to a Solyndra installation costing about half that of a regular flat-panel installation, Solyndra CEO Gronet says. Another major difference between the solar alternatives is in the way they are manufactured. While traditional flat panels are assembled from photovoltaic cells made from silicon, Solyndra tubes are made from a less expensive thin-film of semiconductor material. This material – comprised of copper, indium, gallium and selenium – is deposited on a glass tube, which is nested inside another glass tube. The outer tube concentrates sunlight and protects the solar film on the inside tube. Finally, unlike most traditional solar-panel makers, Solyndra’s management is not targeting the residential market. Instead, Solyndra’s solar tubes are being sold through installers exclusively to the commercial rooftop market. Gronet figures this market adds up to about 30 billion square feet of warehouse, supermarket, factory and other commercial rooftop space in the U.S. alone.