La sperimentazione contemporanea sugli involucri cromogenici

A paradigm of our times is lowering the consumption of electric energy produced from conventional sources, a concern tied to limiting greenhouse gas emissions, without forgetting the need to mitigate the effects of climate change as well. Construction – as we know – is one of the sectors responsible for peak levels of consumption of electric energy. In recent years, emissions have risen in this sector to a greater extent than any other, though rates have levelled off in the last decade. But energy consumption by systems of heating, ventilation and air conditioning continues to rise, driven by growth in the demand for thermal comfort, as well as changing lifestyles. A building’s envelope regulates its thermodynamic system. One of the most effective ways of reduce the energy consumption of a building is to optimise its envelope. Experimental research, in which technological-environmental considerations play a leading role, has registered some intriguing advances in past decades in the development of a new adaptive-selective role for building envelopes, the goal being to arrive at an envelope capable of interfacing with its own surrounding environment, so as to formulate, from the resulting interactions, responses suited to the dynamics of the climate factors encountered in a given day or year, thus ensuring optimal quality of living while guaranteeing elevated levels of wellbeing for all users, in terms of temperature, luminosity, air quality and noise, all this with levels of energy consumption that are limited, and actually trending towards negative. The thermal performance of the envelope is directly proportionate to its mass and to the thickness of the insulation on its outside surface. Overall energy efficiency, on the other hand, is a far more elaborate process. Thermal analysis shows that, if the effects of structural elements, such as thermal bridges, are taken into account, as well as imperfections in the installation of the insulation, air losses and deteriorating materials, then insulation plays a role, but as much as necessary. In buildings with low energy consumption, for that matter, insulation should not be considered the sole method for obtaining the best possible thermal performance from the envelope. Solutions such as the use of phase change materials and chromogenic technology to control solar radiation can contribute significantly to the energy balance of the entire building.