Although the dimensions of the present test fapade are smaller than required by the Norwegian building regulations, the measurements give an indication of the building-physical consequences of an integrated collector faqade. During the summer period, the collector and the wall layers underneath are cooled when the solar system is operative. The temperature in the wall layer directly behind the solar collectors was — as expected — higher for the wall without ventilated cavity. Fig. 3 and Fig. 4 show the measurements on June 27, 2003 and July 31, 2003. Here the temperature and relative humidity conditions can be compared for the wall with — and without ventilated cavity, for an active and passive solar system.

The relative humidity on surfaces should be below 80% in order to avoid degradation due to fungal attacks (Geving and Thue, 2002). The most important and simple observation from the humidity measurements is that the relative humidity in the wall without ventilated cavity was — except for very few and short peaks — laying considerably below the critical limit of 80% for the monitoring period since June 2003 (Fig. 5-Fig. 7). The relative humidity in the wall without ventilated cavity revealed an increase at low level (< 50%) during periods of days with low solar irradiation and high relative air humidity. However, the present construction secures that the relative humidity in the wall reaches the low RH-values with improving weather conditions.

01

Collector fagade without ventilated cavity (green absorbers): Compared are the temperature and the relative humidity measurements in the collector fagade from June 27 when the solar system was operative and July 31, 2003 when the system was not operative. RH_ref is the relative humidity of the ambient air.

Time [Day — Month]

Fig. 5. Measurements in September 2003. Shown are the solar irradiance, the ambient temperature, relative humidity of the ambient air (RH_ref) and the relative humidity RH_int. up, measured between thermal insulation and vapour barrier.

Time [Day — Month]

Fig. 6. Measurements in October 2003. Shown are the solar irradiance, the ambient temperature, relative humidity of the ambient air (RH_ref) and the relative humidity RH_int. up, measured between thermal insulation and vapour barrier.