Experimental system for long term aging of highly irradiated tube type receivers

Abstract

Tube type receivers are being designed with codes that underestimate the thermo-mechanical fatigue and do not consider the effect of ultraviolet radiation. The effect of those phenomena in the receiver durability must be estimated from long-term aging tests, which are best carried out in a solar concentration facility. For this purpose, a solar dish, which was initially coupled to a Stirling engine, has been transformed into a test laboratory capable of reproducing the severe solar radiation concentration and temperature conditions typical of solar central tower receivers. In this facility, the temperature and the solar radiation density are controlled as independent variables. On one hand, the solar radiation density can be adapted to the test required level moving the sample along the dish optical axis. On the other hand, the temperature is controlled by an air flow, which is used as the heat transfer fluid. A test bed, including all the required elements for controlling the temperature and the solar radiation density, has been built up to satisfy certain solar irradiance and temperature ranges. So far, the solar dish has shown to be a very versatile facility for testing materials aging under high solar radiation densities.