A. Haberle, C. Zahler, F. Luginsland, M. Berger

PSE AG, Emmy-Noether Str. 2, 79110 Freiburg, Germany
ah@pse. de, +49.761.47914-14

Abstract

Industrial process heat in the temperature range of up to 250°C is a huge but almost untouched field for solar thermal technologies. State of the art non tracking collectors have their limits at a maximum operation temperature of 150°C. Higher temperatures can be reached with concentrating collectors, which are mostly developed for solar thermal power generation with an operation temperature higher than 300°C and a field size of at least several MWp.

Only a handful of companies and institutes target the enormous potential for solar industrial process heat, which can be defined by an operation temperature range of 100°C up to 250°C and a power range of around 50 kWth up to a few MWth (peak capacity). Plenty of applications for this power and temperature range can be found e. g. in the food and textile industries but presently the most attractive option is solar thermally driven air conditioning. PSE AG developed a linear concentrating Fresnel collector, that uses individually tracked reflector rows to concentrate direct solar radiation to a stationary linear receiver. The Fresnel approach offers a relatively simple and low cost construction with low wind loads and high ground coverage, which makes this technology well suited to be installed on flat roofs.

In December 2005 a first prototype of the PSE linear Fresnel process heat collector was installed in Freiburg, Germany. The collector was operated and evaluated in co-operation with the Fraunhofer Institute for Solar Energy Systems. A second prototype with 132 m2 (66 kWp, th) aperture area was installed in Bergamo, Italy to power a H2O/NH3 absorption chiller. The complete solar cooling system is operated and monitored since August 2006 to evaluate the system performance as well as the performance of the individual components. The third installation with 352 m2 (176 kWp, th) was installed in late 2007 to power a double effect LiBr/H2O chiller at the University of Seville, Spain. The latest installation is a solar cooling system with a H2O/NH3 chiller at a winery in Tunisia.

In this paper we present our experience with the construction and give design values and measurement results of the collector prototype and demonstration systems.

Keywords: linear Fresnel, concentrating collector, process heat, solar cooling