An evaluation of chromic glazing as smart material in high-rise office building facades within the scope of sustainability

Abstract

Today, buildings have a large amount of energy consumption throughout their life cycle, starting from the production stage, including the use and demolition processes. Heating, cooling, and lighting energy used in buildings cause depletion of energy resources and significant problems such as global warming. Therefore, the importance of sustainable architecture and energy-efficient building design should be the target. The facade is a building element that separates the interior and exterior environment in buildings and is an interface that interacts with physical, chemical, and biological factors throughout the building life cycle. Due to the interaction with the outdoor conditions, most of the energy-loss of a building occurs in the facade, especially in the window systems. In high-rise office buildings, facade systems with high window to wall ratios have become widespread in today's technology due to changing user needs and aesthetic values. Factors such as daylight, visual, and thermal comfort on the facades of high-rise office buildings affect the quality of the work, interior comfort conditions, and energy consumption. Transparent elements on the high-rise office building facades are important factors for user comfort and annual energy consumption. Technological developments in materials science and architecture allow the development of new facade materials consequently. In this context, innovative window systems have been developed to prevent and minimize energy gains and losses. Smart materials, which are thought to be of great importance within the scope of sustainability, have become a new research area. Smart materials, which are used and intended to be used in many fields of architecture, also have a wide extent for facade technologies. Today, chromic materials, one of the most advanced groups of smart materials, are generally used in window systems. The main varieties of smart windows are film-coated window systems consisting of electrochromic, thermochromic, or photochromic materials. In these innovative window systems, the window aims to balance heat losses and gains by changing the opacity level according to the solar radiation intensity to provide thermal insulation and lighting control. It is aimed to provide user comfort by balancing heating, cooling, and lighting loads. In this study, the features, examples, and control strategies of electrochromic, thermochromic, and photochromic window systems, together with a preferred window technology today, are explained.