| 摘要 |
<p>A solar collector element (10) having an inner tube (11) through which a fluid can be passed, an outer glass tube (12) enveloping the periphery of the inner tube and defining an evacuated space (13) between the two tubes, and a solar selective surface coating (14) deposited on the outer surface of the inner tube. The surface coating is deposited as three layers, an inner layer (15) composed of a metal which exhibits high reflectivity in the infra-red spectral range, an outer layer (16) composed of a material which behaves as a semiconductor at collector operating temperatures and an intermediate layer (17) which is composed of a dielectric material. The materials of the respective layers are selected such that the refractive index mismatch between the inner layer (15) and the intermediate layer (17) is greater than it would be between the inner layer (15) and the outer layer (16), in the absence of the intermediate layer.</p> |
