Collectors are perhaps the most researched and tested part of the solar thermal system. They have been subject to technical development to improve the efficiency of the historical flat-plate collector design and have additionally evolved in other directions through the use of new materials, new designs and cost bases. The increased competition in Europe due to the importation of collectors from manufacturing areas in the East, has shifted the balance between flat-plate and evacuated-tube collectors and placed new requirements for effective assessment of quality, given the lifespan of the use.
European standards for the testing of collectors have been defined for factory made collectors EN 12975, factory-made systems EN 12976 and custom-built solar systems EN 12977. These define tests for performance standards as well as tests for durability and weatherproofing. The collector testing is carried out at a number of centres throughout Europe, many of which publish the result certificates online.
It should be remembered, however, that it is effectiveness of system in use that is most important and that some of the significant variations in collector performance may not be reflected by corresponding increases in actual system performance. Testing to the European Solar Keymark standard has become increasing the adopted norm and all compliant collectors are marked with the logo shown below.
Solar Keymark Website
The Solar Keymark was developed by ESTIF, the European Solar Thermal Industry Federation and CEN with the support of the European Commission. The Solar Keymark is a voluntary third-party certification, the Keymark scheme was developed to standardise quality test and encourage the expansion of the European solar thermal market by improving market confidence in solar products.
As well as EN 12975/ EN 12976 or EN 12977 results as appropriate, certification
requires additional quality control and factory visits from ESTIF or their agents.
Most product test results can be downloaded via the following website.