In the present work, a simple prototype of a PCM glazing system has been proposed and its energy performance has been analysed and compared with a conventional fenestration. The two glazing technologies were installed on an south facing outdoor test cell, in a temperate sub-continental climate. The surface temperatures, transmitted irradiances and heat fluxes of both the PCM glazing and the reference fenestration were measured during an extensive experimental campaign. Summer, Mid-season and Winter days were considered during the analysis, in both sunny and cloudy weather conditions, in order to assess the energy performance of the PCM glazing under different boundary conditions.

The experimental results have highlighted a good ability of the PCM glazing to store solar energy and to smooth and delay peak values of the total heat flux. In summer the PCM prototype allows the energy gain to be lowered by more than 50%, compared to the traditional fenestration. In winter, a suitable reduction in the heat loss during the day can be observed, but the direct solar gain is also drastically reduced and the application of this technology for passive solar heating purpose might not always be effective. The obtained results have pointed out the promising performance of PCM glazing, even though a careful integration of the PCM glazing component with the control strategies of the indoor air temperature (e.g. night cooling) is necessary.