Evaluation of Solar Combisystems – Recommendations for Improving the Thermal Performance
Abstract
Increasing market development of solar combisystems (SCS) can help to reduce the primary energy demand of buildings and hence the emission of green house gases. To support this market development it is important to strengthen consumer confidence in solar combisystems. An important aspect for achieving this goal is to ensure the performance and quality of the systems under real operating conditions. During the three year project “CombiSol – Standardisation & Promotion of Solar Combisystems” (2007 to 2010) which was supported by Intelligent Energy Europe, 45 solar combisystems installed in 4 European countries (Germany, France, Austria and Sweden) were evaluated in terms of qualitative inspection and quantitative in-situ monitoring according to Jähnig et al. (2008) and Letz et al. (2010a). The objective was to gather information on the installation quality and the thermal performance of solar combisystems under real operating conditions and to compare the results to the ones from laboratory testing. The large variety of SCS offered on the market and the deviation in installation quality makes it difficult to predict the energy savings that will be achieved by the SCS under real operating conditions. In general it can be stated that the performance of the prefabricated components has improved, but the installation quality is still an important factor influencing the thermal performance of SCS. In this context, the term installation quality includes all aspects of installation such as the interconnection of different system components, thermal insulation quality and controller settings. The results of the here applied holistic evaluation approach combining qualitative data from inspection and quantitative data from in-situ monitoring shows potentials for the improvement of the thermal performance of SCS as demonstrated in Ullmann et al. (2010). From the comparison of qualitative data with the corresponding quantitative data, installation aspects were identified as the largest impact factors on the thermal performance. In this paper the evaluation results gathered within the CombiSol project will be presented. Recommendations concerning the improvement of the installation quality of SCS will be described on the basis of the thermal performance of the evaluated systems.