Ms van der Burgt, what exactly happens inside a smart photochromic glass film when the sun is shining? And how do your films distinguish themselves from normal sun-shading films?
Julia van der Burgt: Our self-regulating window film changes its colour when the sun is shining: the higher the sunlight intensity the darker the tinting. In this way, the light is only blocked when necessary. During the evening or on clouded days the film is transparent while in bright sunlight the heat and sunlight are blocked without obstructing the view outside. Compared to normal, static sun-shielding films you benefit more from natural sunlight for heating and lighting in winter and early morning hours. This reduces the energy consumption of buildings for both cooling (air-conditioning) and heating.
How exactly does your photochromic film differ from other “smart” glazing solutions such as electrochromic or thermochromic glass? And what are the most important practical benefits in your opinion?
Julia van der Burgt: The principal difference between our and electrochromic glass is its simple and low-cost (retrofit) applications since no electric cabling is required. Beyond this, since the film adjusts itself, the sunlight conditions indoors are constantly optimised without requiring manual control or separate sensors and activations. Thermochromic glass has similar advantages but, as a rule, blocks out more sunlight in its transparent state. Without strong UV radiation our film is almost as transparent and clear as a normal window.
Where do you see the most exciting application areas for photochromic films? And how do you think they can contribute to energy savings and thermal comfort in buildings?
Julia van der Burgt: I see the highest potential in retrofitting existing buildings whose energy consumption must be reduced. To achieve climate targets enormous energy savings are needed. This is why there is a great demand for low-cost solutions, which can be deployed quickly on a large scale. Our films can reduce the need for air-conditioning systems and, hence, power consumption, without increasing heating needs in winter combining energy with daylight comforts.
