Behaviour of the electrochromic glass in the Mediterranean area

For several years, our university research group is interested in innovative materials in the field of energy saving, with particular attention in transparent building components, regarding, specifically, the use of electrochromic glass (EC). The EC glazing elements are able to change, under user control, the colour intensity of the glass itself which, going from light to dark, can shield 97% of visible light transmission and 99% solar incoming radiation. This chromatic change occurs through a chemical process of reversible oxidation-reduction that modifies, considerably and dynamically, the solar factor g (SHGC Solar Heat Gain Coefficient) and allows, at the same time, to maintain the visibility and the relationship outwards. This technology, initially studied also from some European industries, is currently marketed only by an American company that has done all the tests required by U.S. regulations and it is now preparing to operate in Europe. The high sunshine that characterizes the climate of the Mediterranean regions makes this technology particularly interesting in relation to indoor comfort, energy savings and consequently the environmental respect, that the use of these glass could bring. Currently no specific studies, full scale, have been set for testing and evaluation of the EC in this very challenging. Our research group built, for this purpose, two identical test rooms for exposure, size (4x4x2.70 m) and composition of the envelope. In the first room we implemented low-emission glass and in the second one EC glass. Indoor comparative measurements have performed regarding the hydrothermal characteristics and at the same time all external meteorological parameters were recorded. In this paper we present in detail the results of this experiment and the conclusions for the tested period.