Refine
Is part of the Bibliography
- yes (4)
Review
- editorial review (2)
- peer-review (2)
Document Type
- Article (4)
Institute
Language
- English (4)
Version
- published (3)
A Dynamic Multinode Model for Component-Oriented Thermal Analysis of Flat-Plate Solar Collectors
(2015)
A mathematical model of a flat-plate solar collector was developed on the basis of the physical principles of optics and heat transfer in order to determine collector’s component temperatures as well as collector efficiency. In contrast to many available models, the targeted use of this dynamic model is the detailed, theoretical investigation of the thermal behaviour of newly developed or adjusted collector designs on component level, for example, absorber, casing, or transparent cover. The defined model is based on a multinode network (absorber, fluid, glazing, and backside insulation) containing the relevant physical equations to transfer the energy. The heat transfer network covers heat conduction, convection, and radiation. Furthermore, the collector optics is defined for the plane glazing and the absorber surface and also considers interactions between them. The model enables the variation of physical properties considering the geometric parameters and materials. Finally, the model was validated using measurement data and existing efficiency curve models. Both comparisons proved high accuracy of the developed model with deviation of up to 3% in collector efficiency and 1 K in component temperatures.
A dynamic flat-plate collector model for parametric sensitivity studies on polymer-based collector designs was developed. Validation using experimental results of conventional flat-plate collectors showed satisfying results especially regarding the calculation of individual part temperatures of a collector. The model was used to predict system efficiency as well as individual part temperatures in order to analyse a polymeric collector approach in comparison to a conventional collector. The simulation results showed that the fractional energy savings of systems with conventional flat-plate collectors cannot be reached with the analysed polymeric collector approach. Also the stagnation temperatures of more efficient approaches are too high for low-cost polymeric materials. The exemplary analysis of annual temperature loads of the backside insulation for different approaches proved the necessity of careful collector design aiming at temperature reduction for all individual collector parts.
The climate specific effectiveness of solar DEC-systems and relevant preferable adaptions of the system design have been so far predominantly analysed based on individual simulation for selected sites. In order to systematically deduce design-specific outline data for the application of the solar DEC-technology at climatically different sites a methodological zoning approach was further developed. A subsequent meteorological analysis for 17 sites mapping the world climate creates a transparent understanding on the activity of the specific system components. This results in a comprehension on the site-specific effectiveness of solar DEC-systems and provides insights on principally relevant and efficient system configurations.