Monitoring of a transparent insulation system (TI) at a demonstration project in Graz Maria Trost

Highly efficient and economical advantageous transparent insulation structures, which were composed by different foil materials, were examined and developed in this project at Joanneum Research, Institut für Kunststofftechnik. A pilot system was built for the manufacturing.

A structure on the base of cellulose triacetate was mounted on a demonstration object in Graz Maria Trost (single-family low-energy house).

Monitoring on heat gain and examination of moisture and summer overheating behaviour were carried out on an adapted monitoring field in the transparent insulation façade on the inhabited object.

The monitoring was carried out during a heat period, during which the TI system was not yet installed and also during two heating periods (with one extreme hot summer period in-between in 2003) where the TI system was mounted.

The gain from the TI system during the heating period was excellent in comparison to other TI systems of high quality. The monthly determined effective U-values were with one exception in December 2002, all negative (on the side of energy gain). The gain from the TI system (the difference to the losses of the opaque wall of the same object) was 137 kWh/m² during the heating season September 2002 – April 2003 and 133 kWh/m² during the heating season 2003-2004. The moisture behaviour in the TI structure and in the wall construction behind were shown to be unproblematic. There were no condensate formation thanks to aimed ventilation openings. The water vapour pressure in the structure was in general linked to the surrounding air.

The object has a large roof with a large over-hang, which adequately prevents summer overheating on the second floor. There were, on the other hand, on the ground floor, in August – lower solar altitude and high outdoor temperatures – high indoor temperatures, which were however accepted from the inhabitants.