P 1041 – Optimisation of the operating principle and the use of energy in sandwich construction with energy accumulation, energy distribution and insulation
Industrially manufactured sandwich elements with additional trapezoidal steel sheets on the outside were connected together in the FOSTA project P 779 to form the so-called SEA air collector (SEA = Sandwich Energy Accumulation). Due to the cross-section of the trapezoidal steel sheets, channels are created on the outside when the individual components are joined together, through which air can flow. When the sun shines on the south facade and the roof surface, the SEA air collector can produce an annual energy yield of approx. 160 kWh/m² in the form of heated air.
Within the scope of the present project, it was investigated how a further improvement of the energy yield of this collector can be achieved by optimizing physical and design parameters. In order to investigate the individual optimization aspects, a research approach consisting of measurement, simulation and calculation was chosen. In laboratory measurements, the positive influence of a transparent cover in the form of a solid polycarbonate plate on the efficiency and temperature level of the SEA collector could be quantified. A change in the profile geometry of the absorber as well as an adaptation of various design aspects to increase heat transfer also proved successful. Ultimately, this resulted in an aesthetically pleasing collector in which all variants continue to comply with the principle that only components that are available on the market as individual components are used. By means of laboratory measurements, the mass flow dependence of the investigated collectors was precisely clarified and efficiency curves for three SEA collector variants were generated. The accompanying simulation and calculation showed the range of optimum air duct heights for flat or trapezoidal absorbers, the effect of the angle of incidence, different absorption coefficients and collector lengths on the efficiency and temperature level of the collectors. Using a model hall, the contribution that collectors can make to the energy utilisation concepts for heating and cooling by using different system variants of secondary energy generators and the integration of an energy storage system was shown in a yearly analysis with reference weather data, resolved by the hour. With regard to cooling, it was shown that the possibility of full solar coverage can be assumed even without energy storage. With regard to the energy use of heating, however, this appears to be possible only with the integration of an energy storage system.
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FOSTA – Research Association for Steel Application