BIONICOL · Development of a bionic solar collector with aluminium roll-bond absorber

The aim of the project is to develop solar collectors with absorbers which feature bionic channel structures (FracTherm®" structures), which are multiply branched in a fractal way in order to obtain a uniform flow distribution, a low pressure drop as well as a high thermal efficiency. The absorbers will be built of aluminium using the so-called roll-bond process. Small solar absorbers have already successfully been built in a previous research work. It is now necessary to develop collectors with typical dimensions needed for the market up to a prototype stage and demonstrate their efficiency and functionality as a basis for a following series production. It is expected that high-efficiency collectors at low costs can be obtained as a result of the project. The collectors are to be investigated for a wide temperature range in order to cover various applications. To reach the mentioned aims, the FracTherm® algorithm is to be developed further and the obtained designs have to be produced, evaluated and optimized. Moreover, the possibilities and constraints of the roll-bond production process have to be investigated in order to find out the best possibilities to produce a solar absorber with maximum efficiency and minimum costs. One of the very important tasks of the project will be the coating of the absorber after its channels are produced. Finally, the absorber has to be mounted into a collector casing and thus also has to fulfil a number of requirements. The target of a prototype and small-series production is to demonstrate the possibilities of manufacturing FracTherm® solar collectors with variations of the absorber. In order to prevent corrosion, it is necessary to work on appropriate heat transfer fluids. It is intended to build demonstration systems in various sites in Europe which are operated for more than one year within the project. The final objective is to evaluate the competitiveness of the developed solar collectors with state-of-the-art products."