Ufheil, M.M.UfheilGoetzberger, AdolfAdolfGoetzberger2022-03-082022-03-081992https://publica.fraunhofer.de/handle/publica/319973Within the framework of the passive solar energy research performed at the Fraunhofer Institute for Solar Energy Systems, a transparently insulated device, constructed with a double-sheet design, was developed for the exterior walls of buildings. Using the program TRNSYS, transient computer simulations estimated yearly heat gains of 41 kWh/qm for a massive south-facing wall in Freiburg. An opaque insulation with an U-value of 0.7 W/qm K (WVSO '82) has yearly heat losses of 57 kWh/qm. The energy efficiency of the TI curtain device was confirmed by experimental results. The absorber is manufactured by gluing a black, selective nickel laminate to a Polytetrafluoraethylen (PTFE) substrate. In March 1992, a sputtering technology, developed at the FHG- ISE, made it possible to cover large area PTFE substrates. Thus, a cost efficient manufacturing process for large absorber areas was enabled. In summer the double-sheets can either be rolled up or can be ventilated from behind by natural conve ction. First cost analyses show that the transparent insulated curtain device is competitive today.enpassive solar energyPolytetrafluorethylenPTFEtransient computer simulationtransparent insulationTRNSYS621697conference paper