Components in a CSP plant are subject to heavy environmental conditions. These can lead to a quick degradation of their material. To test the durability of the components, accelerated ageing tests for parabolic trough receivers and CSP mirrors are performed. These tests evaluate the effects of specific influences, such as changing temperatures, humidity, and sand abrasion.
Overheating and Thermal Cycling Tests
The overheating test is an accelerated ageing test for the absorber coating of the receiver. Oil receivers are electrically heated to a temperature of 478 °C for duration of 1000 hours. For an accelerated thermal cycling test, we recommend to perform 100 cycles with temperatures from 200 °C to 478 °C. Test result is the change in receiver performance; hence, the performance is measured before and after the test.
Bellow Fatigue Test
In order to test for bellow fatigue, the absorber is fixed and the glass envelope is pushed back and forth. During the test, the absorber is heated with internal electrical heaters until the maximum operation temperature is reached. Through the relative movement of the absorber and the glass envelope, the bellows are expanded and compressed with an amplitude equivalent to the one during operation in the field. The quality of the bellow is determined by measuring heat losses of the receiver before and after the ageing procedure.
Receiver glas and Mirrors
The durability of the anti-reflective coating is tested on small curved glass samples at the DLR QUARZ Centre. We also offer accelerated ageing tests for CSP mirrors in close cooperation between the QUARZ Centre and the Spanish research centre CIEMAT (Centro de Investigaciones Energéticas Medioambientales y Tecnológicas). The following tests are conducted:
The DLR QUARZ Center operates outdoor facilities in Spain and North Africa with exposure sites to verify the accelerated ageing tests which are conducted in laboratories. A central goal of these tests is to understen the underlying mechanisms that lead to degradation effects.