Ritter Solar in Dettenhausen is the largest manufacturer of evacuated tube solar collectors in Germany.

Components and complete solutions

The company supplies both components and complete collector panels to leading solar technology companies throughout Europe, and aluminium extrusions are an important construction material in the panels for such things as the frame.

Unlike photovoltaic solar panels that generate electricity, Ritter Solar’s solutions turn the sun’s energy into heat. The components feature evacuated tubes, which are among the in best performance and efficiency.

Evacuated tubes can be compared to a warm drink flask made of two glass tubes with a vacuum between them. Ritter Solar’s components use an outer tube that is transparent and the inner tube coated with an absorbent.

The air in the center of the inner tube becomes very hot, around 230-250 degrees Celsius. A U-shaped pipe fitted into the evacuated tube circulates a liquid that is heated by the air in the evacuated tube and carries it away.

Ritter Solar makes complete collectors and heat exchanger units using the evacuated tube technique, where the evacuated tube is complemented with highly polished reflectors, called CPC (compound parabolic concentrator) mirrors, to increase the efficiency. Everything, including the necessary pipe system, is fitted into modules with vertical and horizontal frames of aluminium extrusions.

Aluminium extrusions from Hydro

Upwards of 30 aluminium extrusions are used in Ritter Solar’s products, of which five to 10 are used in a special solar collector module. The extrusions are made by Hydro’ extrusion plant in Nenzing, Austria, which was also involved in product development and optimization of the design and properties of the extrusions.

The choice of aluminium extrusions as construction material was mainly decided by the demands for good corrosion resistance and low weight. The panels are mounted on the outside of the roofs or walls of buildings and are thus fully exposed to the elements.

The low weight of the modules makes handling the units easier and simplifies installation. The extrusions have multifunctional designs that facilitate mounting and dismantling, give strong and stable fastening of the evacuated tubes, mirrors and other heat exchanger components as well as providing modules with an attractive appearance and high quality surface finish.

Good cooperation

The extrusions are delivered to Ritter Solar either by the length or finished ready for final assembly. Following extrusion, Hydro processes the extrusions by cutting, punching, milling and drilling as well surface finishing by anodizing and lacquering.

Hydro has also developed a logistics solution for Ritter Solar with intermediate storage that allows just-in-time deliveries of finished components within three days.

“When developing and optimizing the extrusions for our products, the cooperation with Hydro proved very valuable,” says Franz Olbrich of Ritter Solar. “A logistics solution that gives us fast and reliable deliveries is essential for rational and cost effective manufacture.”