The existing plant with 5 000 m² on the roof of AEVG in Graz was built in 2007 and has been successfully in operation since. The plant has been extended with 2 000 m² and the new system is in operation since September 2014.
In this project, the direct comparison of several large solar thermal collectors in one and the same installation is particularly interesting. It will allow collector choices for future large-scale solar thermal plants to be based not only on simulation, but also on the results of a test field under real conditions. Optimized collectors from a new generation are installed with better insulation and special solar glass. A significantly higher solar gain is therefore awaited from this plant than from the one already installed in 2007. First measurements should be available in the beginning of 2015.
In the design phase of the project, SOLID invited European and Asian vacuum-tube and flat-plate collector manufacturers to the comparison. Contracts were signed with 3 European manufacturers. The comparison will be based on the costs per MWh produced energy over the lifetime of the plant.
The heat is sold by SOLID to Energie Steiermark. Investment costs are around 1 Mio. €. “We want to use every possibility to make district heating supply in Graz even more ecological” says spokesman Christian Purrer from Energie Steiermark.
With more than 10 000 m² collectors feeding in the district heating net, Graz has the largest solar thermal area feeding in a district heating in mid-Europe.