Hygro-thermal performance of an opaque ventilated façade with recycled materials during wintertime

This study investigates the thermo-hygrometric behaviour in wintertime of an open-joint ventilated façade, designed to be environmentally sustainable. It is the result of the Horizon Project “RE4 – REuse and REcycling of CDW materials and structures in energy efficient pREfabricated elements for building REfurbishment and construction” and it is composed by prefabricated elements made by recycled materials from construction and demolition waste. The designed façade has been installed in a full scale test-room located in Benevento (south Italy), with typical Mediterranean climate. The proposed analysis suggests that for the behaviour of the designed façade, the main influential factors are the solar radiation and the outdoor air temperature meanwhile the wind effect is negligible. Some mathematical correlations have been found and an empirical model that describes the air temperature in the cavity as a function of the external climatic parameters is developed. These findings could be useful for the assessment of performance of similar facades in the design phase but also for comparing the behaviour in different climates. All tests demonstrate that in winter time, in a humid and rainy climate, the prevalent effect is the insulation and the ventilation does not increase the heat losses. The designed system can effectively control the moisture content in the building envelope materials, ensuring dry surfaces and at the same time avoid the alteration of the thermo-hygrometric characteristics for the bacteria and mould proliferation, ensuring healthy environment and avoiding structural damage.