B.P. Jelle
Norwegian University of Science and Technology (NTNU),
Norway
Keywords: smart window, electrochromic, photochromic, thermochromic, dynamic, controllable, adaptive, solar radiation, energy-efficient, building
Summary:
As the world and its inhabitants are becoming increasingly aware that a shift towards a more sustainable society is crucial for the survival of human life as we know it today for generations to come, there is a growing focus and demand to develop and start utilizing renewable and non-polluting energy sources alongside improved energy efficiency remedies in various sectors, also including the building sector. Within this realm we find the large potential of exploiting the solar radiation in fenestration technologies for daylight and solar heating purposes, also with regard to avoid overheating and subsequent cooling demands during the warm and sunny periods of the year. In this respect, smart windows may play an important role in our future buildings, including both the construction of new buildings and the renovation and upgrading of existing buildings. Smart windows are upon an applied external stimulus able to dynamically change their solar radiation transmittance in the ultraviolet, visible and near infrared region. Miscellaneous smart window materials and technologies do exist and are being improved and tailor-made for their specific applications, together with a development of new ones. Among these smart window materials and technologies there are both controllable (e.g. electrochromic) and adaptive (e.g. photochromic and thermochromic) technologies utilizing many different materials and material compositions with different properties. However, in this myriad of different materials and technologies, it may be difficult to determine which ones should be selected for the specific building projects with their requirements and desired functionalities, be it erection of new buildings or renovation of existing ones. Hence, this study will look into these matters of the miscellaneous smart window materials and technologies including both research-stage and commercial windows, with their different properties, opportunities, advantages and disadvantages. Selected cases where building energy performance simulations have been carried out will also be presented.