Case Study: Twin wall sheet testingIEA-SHC Task 39 INFO Sheet C7.4
May 2015 - PDF 0.38MB
When using polymeric materials for solar thermal flat plate collectors, one distinct difference in physical properties compels us to reinvent the absorber design. Due to the low thermal conductivity of polymeric materials, the absorber, in order to prevent local overheating and to increase the collectors’ efficiency, needs water contact throughout the whole surface. In general only few absorber designs fulfill this requirement, e.g. thin plastic film absorbers, tube absorbers or twin wall sheets. The latter two are in the focus of recent development due to mechanical stability and economic efficiency. In order to investigate changes in the mechanical properties of the used materials as closely to the product as possible suitable mechanical testing methods need to be applied. For pipes, methods to test different mechanical loads already exist, but for twin wall sheets none of these can be applied.