Now that sustainability has become a priority for the architecture and construction industries, innovative solutions are being developed to mitigate the environmental hazard of building operations and carbon emissions. For instance, using new materials and technologies for new-build and refurbishment projects is considered acceptable. One of the main areas of intervention involves HVAC operations, with building management systems being able to adjust indoor and outdoor ambient conditions dynamically.

However, to really think sustainably, considerations should be broader than just environmental and should evaluate factors such as the economy and society. In this regard, liquid crystal dynamic glazing can be considered as one relevant example of materials providing a contribution to sustainability in the three aforementioned areas. This solution is well known in façade and interior design for its good insulation properties, solar control, energy performance and visual comfort. But on top of that, the technology is able to increase the wellbeing of occupants.

Celine Glipa

Dynamic and switchable glass can be used for interiors as well as exteriors. The material behind switchable glazing is the same liquid crystal from a television, computer or a mobile-phone screen. A mixture of liquid crystals and dyes is put between two glass panes. The orientation of the molecules regulates the amount of light passing through. Without voltage, the molecules block the majority of the light, and the glass is dark. When voltage is applied, the liquid crystals change their orientation and the amount of light transmitted, meaning that more light comes in. This transition between dark and bright states is possible in less than a second, creating instant shading. A reduction or increase in the amount of light also regulates the internal temperature. As a consequence, the environment becomes more comfortable, the intensity of the light is regulated and outside views are preserved.

The construction industry knows switchable glass based on electrochromic technology, but this material shows slower switching speed and blue appearance. On the opposite, dynamic glazing, based on liquid crystal technology, is instantaneous and colour neutral. It is a higher-performing alternative, owing to its differentiating materials and technologically competitive advantage. Due to its instant thermal regulation properties, liquid crystal dynamic glazing provides a direct contribution to reducing emissions and HVAC operations. Being able to control the amount of light and heat that is absorbed or dispersed, the need for air conditioning and lighting can be from 10-20% less. Of course, this reduction depends on the exposure of the building and the geographical climate conditions.

In the Middle East, for instance, where solar protection is not a luxury, liquid crystal dynamic glazing can be a crucial material to reduce the need for air conditioning but still have a comfortable light and temperature environment. A recent use case of liquid crystal dynamic glazing in action was shown at the World Expo 2020, in Dubai. In line with the Expo’s central theme, Campus Germany – the German pavilion – showcased the most recent advancements in scientific, technological, economic and social progress. The pavilion was built according to sustainable principles, with a shape made of suspended cubes and steel poles covered by a floating roof and shelled with liquid crystal dynamic glass. The choice of these building elements was due to the different weather conditions that the building had to undergo during the six-month-long duration of the Expo.

With its strong focus on sustainability, liquid crystal dynamic glazing was the technology of choice to guarantee the best natural light conditions and temperature control. The ecological advantage of using liquid crystal dynamic glazing, indeed, had an impact on energy savings. In total, 61 panels of liquid crystal glass were installed, of which 28 were fixed glass panels, four standard doors, and 29 folding doors. These 1.5-metre-wide glass elements were also able to rotate and open, allowing a natural ventilation on cooler days.

Dynamic façades, powered by liquid crystal technology, are therefore able to satisfy two needs harmonically. On the one hand, they help a building achieve its energy efficiency ambition; on the other, they create a comfortable environment, respecting users’ health and wellbeing. Social needs are indeed as relevant when considering materials and processes for any construction project. In countries where green building certifications are setting the standard, programmes such as the Building Research Establishment Environment Assessment Method (BREEAM) and Leadership in Energy and Environmental Design (LEED) have made it clear. A building’s performance must consider societal factors besides economic and environmental. In some other countries, the same sensitivity has been shown. Initiatives and methodologies for building design, like Estidama, indeed want to spread a sustainable mindset for environmental, economic, cultural and social value creation.

Liquid crystal dynamic window technologies prove to have a direct impact on these factors. The glazing supports occupants’ natural body clock rhythms throughout the day, offering a more positive effect on health, wellbeing and, for office spaces, on productivity, as well. By maintaining constant thermal and solar control, this technology reduces PPD (Predicted Percentage Dissatisfaction) from 21% for normal double glazing to six per cent for solar shading glass. Differently said, people working in an environment with ideal balance between light and thermal regulation are less likely to get sick. Research by Merck KGaA, Darmstadt, Germany, the parent company of eyrise®, suggests that a reduction in absenteeism equates to an extra 4.4 days of productivity gained. Translated into financial results, it means a USD 860 million saving on health costs and a USD 82.5 million saving on energy throughout a year.

As the construction industry is expected to consider the challenge towards sustainability beyond sole environmental factors, technologies, such as liquid crystal dynamic glazing, can be crucial drivers for value creation. In the light of the aforementioned considerations, the positive impact is not only on a building’s carbon footprint and a decrease in energy needs but is also on creating happier communities and driving up economic value.

The author holds a double doctorate in polymers and electrochemistry and has been involved with the development of liquid crystal glass from the laboratory to the boardroom. She may be contacted through writing to marianna.trimarchi@merckgroup.com.