Parametric Analysis of Concrete Solar Collectors

Concrete solar collectors offer a type of solar collector with structural, aesthetic and economic advantages over current populartechnologies. This study examines the influential parameters of concrete solar collectors. In addition to the external conditions,the performance of a concrete solar collector is influenced by the thermal properties of the concrete matrix, piping network andfluid. Geometric and fluid flow parameters also influence the performance of the concrete solar collector. A literature review ofconcrete solar collectors is conducted in order to define the benchmark parameters from which individual parameters are thencompared. The numerical model consists of a 1D pipe flow network coupled with the heat transfer in a 3D concrete domain. Thispaper is concerned with the physical parameters that define the concrete solar collector, thus a constant surface temperature isused as the exposed surface boundary condition with all other surfaces being insulated. Results show that, of the parametersinvestigated, the pipe spacing, ps, concrete conductivity, kc, and the pipe embedment depth, demb, are among those parameterswhich have greatest effect on the collector’s performance. The optimum balance between these parameters is presented withrespect to the thermal performance and discussed with reference to practical development issues.

Effect of weather and the hybrid energy storage on the availability of standalone microgrid

This paper presents a model for availability analysis of standalone hybrid microgrid. The microgrid used in the study consists of wind, solar storage and diesel generator. Boolean driven Markov process is used to develop the availability of the system in the proposed method. By modifying the developed model, the relationship between the availability of the system with the fine (normal) weather and disturbed (stormy) weather durations are analyzed. Effects of different converter technologies on the availability of standalone microgrid were investigated and the results have shown that the availability of microgrid increased by 5.80 % when a storage system is added. On the other hand, the availability of standalone microgrid could be overestimated by 3.56 % when weather factor is neglected. In the same way 200, 500 and 1000 hours of disturbed weather durations reduced the availability of the system by 5.36%, 9.73% and 13.05 %, respectively. In addition, the hybrid energy storage cascade topology with a capacitor in the middle maximized the system availability.