scope:

This document specifies the technical requirements, tests, durability and technical performance parameters of solar thermal receivers for absorbing concentrated solar radiation and transferring the heat to a fluid used in concentrated solar thermal power plants with linear-focus solar collectors. The receivers addressed consist of an absorber tube and an insulating glass envelope tube.

NOTE 1 Most of the test methods included in this document apply to solar receivers used both in solar thermal electric plants with parabolic-trough and Fresnel collectors.

This document includes the definitions of technical properties and characterization of geometry and performance parameters as well as the test methods for optical characterization, heat loss, and durability.

NOTE 2 The experience accumulated so far regarding the different test methods currently available for receiver tubes is not extensive enough to determine which test method is the best; this document describes all the different methods currently available without defining one recommended method.

For the sake of clarity, it is stated here that the thermal loss tests described in this document do not deliver the thermal loss of the receiver tubes when they are installed in commercial solar fields.

Thermal losses obtained by indoor testing on a single receiver are significantly lower than the thermal losses in outdoor, real operating conditions at commercial solar fields. However, the indoor test procedures described in this document are suitable for receiver tube performance comparison.

The thermal losses taken into account for solar field design are obtained by testing complete collectors operating under real solar conditions.