Projects Profile
Project Title
Solar-Thermochromic Composites Films for Smart Windows
Partnership
Prof. George Zheng Chen, The University of Nottingham, UK
Dr. Xianbo Jin, Wuhan University, China
Project Aim
This project aims to develop novel and affordable solar-thermochromic polymer-ionic liquid composite materials on the basis of proven sciences from previous collaborative research between Chen and Jin in the past. Such materials have the potential to enable the solar-thermochromic materials based smart window technology that can significantly reduce the energy consumption for air conditioning in the built environment.
Inspiration for the projects
In summer, air conditioning accounts for the largest part of energy consumption in the built environment, and sunlight is most responsible because, after entering buildings or vehicles through windows, light dissipates most of its energy as heat. Smart windows built from solar-thermochromic materials can partially prevent light from entering the built environment to save energy without interfering human activities. These materials work automatically in response to temperature changes, and hence do not need a control system that increases the cost.
The two applicants and co-workers have developed novel polymer-ionic liquid composite films that change colour, e.g. white to light blue, in response to temperature changes between room temperature and 80oC that can be readily achieved under sunlight. These novel composite materials contain a water-like salt (which is called ionic liquid) whose colour changes when temperature changes. Ionic liquids are very unique in that they do not evaporate when heated and hence enable very high stability in heating and cooling cycles, and also in storage under ambient conditions. In the composites, the microstructure was specially engineered to accommodate the ionic liquid, but the composite materials are still very easy to make, which will help commercialisation.
Commercial Potential and Further Development
The current world production of flat glass (mostly used for windows or walls in buildings) is about 5.3 billion square metres per year with a predicted growth rate of 5.1% per year. However, there has not yet been a developed market for solar-thermochromic smart windows. If the smart window technology may share a quart of the flat glass market (i.e. for those windows facing the sunlight), the commercial potential would easily exceed multibillion-dollars per year. There is also great benefits from energy saving and the related reduction of CO2 emission.
In addition to smart windows, other commercial and social benefits of developing the solar-thermochromic materials come from the aesthetic and other visual effects of colour changing. Related applications are countless, such as outdoor decoration, artistic and commercial displays, containers and packaging, overheating indicators and even toys, particularly when designers are offered with multiple selections which can be readily achieved by using different colouring agents (ionic liquids) in the composites.
