Collector Efficiency Testing — Reduction of Test Duration by Usinga2-Node Collector Model

Up to now all national and international standards prescribe certain boundary conditions like ambient air velocity, level of solar irradiance, etc. for the efficiency test of solar collectors. Although the boundary conditions vary between standards, one requirement is common for all of them: Only measured data with a positive collector output are allowed to be used to determine the collector efficiency. For outdoor tests, this requirement may lead to long test periods due to unfavourable weather conditions. Against the background of a possible reduction of testing costs and the wish to satisfy the increasing demand for collector tests a reduction of the test duration is a desirable option.