Combined solar thermal and heat pump systems within the funding program of large-scale solar thermal systems in Austria - Status investigation and progress report

The Austrian "Klima- und Energiefonds" started 2010 a funding program for the development and further market penetration of large-scale solar thermal systems. The most interesting projects in terms of innovation were selected for a system monitoring, analysis and optimization of about 12 months by a scientific partner. Since 2010 about 25 combined solar thermal and compression heat pump systems (STHP systems) were selected within this framework and for eleven of these systems monitoring data is available. In this paper the selected systems are categorized and findings from the monitored systems are presented. Therefore, the performance of the systems is assessed with technical, economic and ecological parameters. In principle, the compression heat pump suits well to the solar thermal system to generate low temperature heat for space heating purposes and hot water preparation. The compression heat pump acts flexible and generates heat whenever the solar energy is not available. STHP systems show also a very positive effect for reductions of environmental impacts. But lack of standards for planning and realization leads to higher effort, higher risk and costs. Up to now the knowledge transfer by the scientific partners to the market players is essential for the further development of this technology.