It is possible within the Solar Keymark scheme rules to test and certify thermal solar collectors as families. This reduces the effort for the testing by far.

A similar procedure for SDHW systems is now in the stage of development among testing institutes in Europe. The “Centre Scientifique et Technique du Batiment” (CSTB) in France

developed the “Solen software” for the calculation of the efficiency of solar thermal heating systems in buildings according to prEN 15316-4.3:2006 [3].

The software has now been used to extrapolate between two tested forced-circulation systems. The systems were tested at Fraunhofer ISE using the Dynamic System Testing (DST) procedure according to EN 12976-2. The basic differences between the two systems are the size of the collector array and the size of the storage tank

System A: 2 collectors, Aa=4,72 m2; Storage tank, 295 l

System B: 3 collectors Aa=7,08 m2; Storage tank, 380 l

The following table shows the deviation between test results and simulations done using the “Solen software”. The simulations are adjusted with the test result of the other system in the “system family”. It is seen that for the location Davos, for instance, the deviation between test result and the simulation is smaller than for Athens. Looking at this particular system family the deviation for the locations Stockholm and Davos are very small. More tests and simulations have to be done to validate the procedure.