Towards a Unified Standard for Solar Air Heating Collectors
Abstract
Although solar air heating collectors have some significant advantages in comparison to liquid heating collectors, currently they have only a market share of less than 1% of the solar collector world market. The main advantages of using air as heat transfer medium are the absence of stagnation and freezing problems and a reduced tightness requirement. This makes it for instance easier to integrate solar air heating collectors into façades. Different air heating collector types available range from non-covered open-loop collectors for space heating support at low temperatures, to high performance evacuated tube collectors with high efficiencies at increased temperatures. An important barrier for a broader use of solar air heating collectors is the lack of common standards for testing to ascertain quality and performance. The Fraunhofer Institute for Solar Energy Systems ISE is currently working on the development of testing standards for covered and noncovered air collectors, the development of simulation tools to calculate solar gains of solar air heating systems as well as the improvement of solar air heating collector technology. This work is done in cooperation with industry within the project ‘Luko-E’, which is co-funded by the German ministry for the environment. In the following the status of the work is described.