Highly Efficient Solar Absorbers Produced by Large Area Electron Beam Deposition

Presented by J. Faber

Cermets based on Al2O3 and Mo have been successfully used as solar absorbers e.g. for concentrating solar power systems. However, its production by DC- and RF-sputtering has extremely low throughput and hence is very expensive.

Electron Beam (EB) evaporation is an alternative for Mo and Al2O3 deposition. Due to simulation results, very good selective optical properties can be achieved by gradually reducing the Mo content in the cermet layer.

Therefore the deposition was carried out onto moved metal strip co-evaporating both cermet components from a double copper crucible. Measured samples showed a solar absorbance of 93,8 % and a normal emittance of 3,6 % at 100°C and respectively 8,2 % at 300°C. Large area EB-PVD of this cermet layer system could be a profitable way to produce solar collector material at high productivity.