NUMERICAL INVESTIGATIONS OF ADVANCED VOLUMETRIC RECEIVER MATERIALS Olena Smirnova 1,2 , Georg Bleiber 2 , Christoph Jakob 2 , Daniel Schöllgen 2 , Thomas Fend 2 and Peter Schwarzbözl 2 1 Corresponding author: Tel. +492203 601 2901, olena.smirnova@dlr.de 2 German Aerospace Center, Solar Research, Linder Hoehe, 51147 Koeln, Germany Abstract This paper presents the results of a numerical analysis of the mass transport and the heat flow through a volumetric solar receiver as a candidate component for a central receiver system for solar electricity generation. The receiver investigated was an extruded honeycomb structure made out of Silicon carbide. The objective of the study is to investigate the influence of slight geometric changes on to the overall performance of the receiver. The results are compared with those of an experimental study. Two numerical models have been developed. One makes use of the real geometry of the channel (single channel model), the other one considers the receiver to be “porous continuum”, which described with homogenized properties such as permeability and effective heat conductivity. The experimental parameters such as average solar heat flux and mass flow were taken into account in the models as boundary conditions. Various parameters such as the average air outlet temperatures, the temperature distributions and the solar-to-thermal efficiency were used for the comparison. The good correspondence between the experimental and numeric results of the both numeric investigations confirms the usefulness of the approach for further studies. Keywords: Volumetric solar receiver; volumetric heat transfer coefficient; solar tower technology 1. Introduction The rising interest in solar energy and its applications has led to an increasing research activity in this area. It belongs to two scientific areas: application of solar energy and new material’s properties investigation. The present paper belongs to second one. The volumetric solar receiver as one of the main components of the system absorbs concentrated radiation and transfers heat to an air circuit, which feeds the boiler of a steam turbine. It has been used in solar energy since about 1985 and has been object of numerous investigations since then [1-4]. The material investigated is an improved Silicon Carbide honeycomb structure based on the state-of-the-art-technology shown in Fig. 1 (left), which has also been applied in the solar tower in Jülich [5]. It has been manufactured by St. Gobain IndustrieKeramik Rödenthal. The photo of the solar tower power station and the volumetric solar receivers are presented in Figure 1. 150 mm 150 mm Fig. 1: Photographs of the Jülich Solar Tower, a part of the single absorber module and the solar receiver during installation According to the short description of the volumetric solar receivers mentioned above the present research work has been undertaken in the network of the project "OVABSOL". It has been divided into two parts: experimental and numeric. The numerical part has been started to mainly develop tools, which can be used to