Harald Drück

Impact of Ageing on Thermal Efficiency of Solar Thermal Collectors

Today it is common practice to calculate the performance of solar thermal systems or solar collectors based on the results of a thermal performance test carried out with a new solar collector. However, for an integral assessment of solar thermal collectors and systems, it is necessary to consider the change of performance with time due to degradation effects. Degradation effects like a reduced transmittance due to deposits on the transparent collector cover or a reduction in the absorption coefficient of the absorber due to high temperature oxidation mechanisms may result in decreased collector efficiency. Up to now it is not possible to take these degradation effects into account, systematically.

Testing of Control Equipment for Thermal Solar Systems According Pren Ts 12977-5

Since 2004 the three parts of the European Standard series ENV 12977, Thermal solar systems and components — Custom build systems are under revision and, among others, an additional part, titled “Performance test methods for control equipment” was added. The new part substitute and complement the specifications concerning testing of solar loop controllers and temperature sensors previously given in ENV 12977-2:2001, Annex B. Due to an increasing complexity of control equipment used for solar and the remaining heating systems and in order to test controllers as detailed as it is e.g. already common for solar collectors and hot water stores, an appropriate part of the standard series dedicated to controllers and control equipment was required.[1]

Solar Keymark Testing of Solar Thermal Products

The Solar Keymark is the official CEN certification scheme for thermal solar collectors and factory made thermal solar systems. The Solar Keymark requires that the products fulfil the requirements of the European Standard series EN 12975 and EN 12976 and that this is confirmed by an accredited test laboratory. Furthermore, additional requirements such as a yearly inspection of the production line and a physical inspection of the product every second year have to be fulfilled.

Development of a mobile, stand-alone test facility for solar thermal collectors and systems

Testing of solar thermal systems and components requires different standards and thus different test facilities. Usually each facility is individually designed and constructed for tests according to a specific test method. For performing tests of solar thermal systems and collectors according to the most popular standards, test laboratories or manufactu-rers have to invest a huge amount of staff time, resources and capital to set up the required test facilities.