If you follow the world of dynamic façades, and particularly dynamic glass, you will notice a lot of information that can be confusing at best, when it should be straight forward. Let’s try the KISS approach and Keep it Simple.
If you design a façade, what is it that you want? Performance? Aesthetic? Value? Probably a combination of these three things. Could one thing influence another? Sure, they can all play a part in creating the architecture that we enjoy and feel comfortable with. Do different people within a design team influence the direction of these? Of course. The information available needs to be concise and to the point to help in this collaboration of thoughts.
In our current society I think it is generally true to say that we like transparency. We like to believe we are transparent in our lives. We certainly like to have the connections from one space to another, be it internal or external, that transparency brings. Of course glass is the perfect material to enable high levels of transparency in our architecture today. Larger production capabilities have meant greater use of glass in both minimalism in framing and joint design. What about the size of the glass you intend to use? The answer depends on who you design for. With this increased usage of glass comes a high degree of responsibility for how much energy is allowed through the façade. With the knock on effect of how much cooling will then be required to dissipate the subsequent energy build up. Many ideas, both theoretical and practical, have been proposed, and used over decades of façade design. All trying in one way or other to reduce the amount of energy hitting the glass that we like for our transparency. This energy generally passes through the glass and causes solar heat gain. Sometimes this is desired. But as climate change becomes more of a concern in the world today and into the future, these solar heat gains need a degree of control.
So what of these ideas to control the energy coming through façades?
Initially, there was very little. Excitement in the use of glass has been driven by a desire to create and play with space and light. Also tied, in varying degrees, with keeping the climate in check. Lots of glass, beautiful spaces. The question is “does that always make for great architecture?”. We are all familiar with great pieces of architecture opening up light and space but falling down in someways in performance. Early usage of single glazing was replaced over time by double glazing, with IGU patents stretching back over 100 years. Double glazing begat triple glazing, now common in northern climates and energy-conscious societies. Quadruple glazing and multiple cavities are already being tried with varying degrees of success. With IGU advancements, came the introduction of coatings.
First, low emissivity coatings trying to stop heat escaping, then better performing solar coatings, which are wavelength selective to reduce incoming infrared light and energy. Then, a combination of both principles started to be introduced. These coatings are multiple stacks of materials laid down in atomic thicknesses, mainly on magnetron coating lines. On the whole they remain transparent. Good for glass. Good for us. Some would argue however, that coatings have reached their physical limits and yet we are still not able to design, in most regions, a glass building that meets the ever tightening energy codes that are being introduced around the world. Why is this? The codes are rightly driven by an increasing awareness into overall energy efficiency, reducing our overall dependence on fossil fuels.
To help this cause, façade design added complexity. Increased performance ideas started driving an aesthetic in architecture embracing, for example, double skins, and their big brother closed cavities. Again why? The main principle in all this seems to use elements that somehow stop the energy of the sun hitting the inner glass and therefore dissipating heat to our interior spaces, which in turn then needs to be cooled. These elements, whether brise-soleil, louvres, blinds, etc, active or passive, tend to be solid to some degree or other. It is true that when fully activated these devices make a very good solar shade. However, they also, to a large extent, severe the transparent connectivity that the glass façade is all about.
What is important here? Answer, energy.
Whether it is the positive energy that gives passive heat gains when we need it, natural daylight when desired, or the energy that brings overheating, which then needs more energy to deal with it. Keeping in mind a society that really likes transparency, what might be some of the solutions? One growing realm in this area is dynamic glass. Given that 90% of our lives now seem to be spent inside somewhere or other dynamic glass can help keep an architectural intent and significantly help the environment we choose to live and work in. With this in mind, many innovative designers and architects are already turning to dynamic façades. A word like ‘smart’ is often overused, but we need to consider what both ‘dynamic’ and ‘smart’ mean in a façade context.
A couple of definitions to think on:-
Dynamic – Characterized by constant change.
Smart – Programmed to be capable of some independent action.
So can glass be programmable and become capable of independent change? Can it also constantly modify itself to suit the variations of a changing environment?
Also, what is wanted from a dynamic glass? A good performance range in both variable light transmission and g-values, good switching speeds across the full performance ranges, good colour neutral rendering, adaptive, intuitive controllability, good value? Again, probably a combination of all the above.
So in this family of dynamic glass, there are currently two differing technologies. Firstly an electrochromic one and secondly a liquid crystal technology – known as eyrise™. Of the two available technologies, only the liquid crystal eyrise™ glass can promote and develop the two leading principles for being both smart and dynamic as per the earlier definitions.
… and here’s why.
Electrochromic glass combines thin films of ceramic metal oxides onto a glass substrate, that then have the capabilities to change their colour as a result of a chemical reaction which happens when an electrical current is applied. Liquid crystal glass, or eyrise™, is a mechanical rotation of crystals within a glass sandwich, again this transition happens when a current is applied.
There is one big crucial difference between these two technologies when it comes to what happens when that current is applied. The eyrise™ glass transition happens immediately and can be programmed, dimmed so to speak. Working uniformly across an IGU no matter what size or shape. Whilst all electrochromic solutions take up to 30 minutes to fully transition to their darker state and are size-dependent. Larger units taking longer to change.
Both technologies change light transmission and both have variable g-values to differing degrees. Again eyrise™ glass can subtly change to suit the ever-changing environmental conditions. Important if performance is a driver. Energy efficiency exactly when needed and in real-time. Eyrise™ technology can also fine-tune immediately. Both in lighter and darker states, in either direction, at any given moment in time. An electrochromic glass does not have this flexibility of control.
So due to the inherent flexibility of control, eyrise™ glass leads the way in these ideas of independent action and constant change. What of colour? Because of the tungsten oxide metals used for the coatings on electrochromic glass they will usually have an inherent blue hue. Tungsten oxide-based electrochromic products are blue because this is the color of the tungsten oxide in its oxidation state (absorbs light in the yellow/red and allows blue to transmit). The technologies can be less blue if the counter electrode is complementary and absorbs a different color in the visible light spectrum at the same time, but this just results in varying ‘shades’ of blue – say a more grey-blue rather than a very ‘blue’ blue – but still the predominant color is ‘blue’ when you have a tungsten oxide-based coating on the glass.
Apart from strong blue tones taking precedent as an electrochromic glass starts to darken, critically the colour rendering index figures drop. This means that surfaces, including foodstuffs and skin tones, can start to be affected by the hue in the glass. Hence in a dark state, some surface will look unnatural.
Eyrise™ liquid crystals can be prepared in almost any colour. All these variations within eyrise™ glass have a high colour neutrality in the darker states as well as also the light state. It can be noticed that some colours are better than others in the colour rendering. In discussions with consultants, and testing on live projects, eyrise™ as an offered solution has been seen to control colour rendering within rigorous specified performance figures for internal spaces eg. galleries, where electrochromic glass has not been able to meet the colour rendering index figures.
A recent study by environmental engineers at Elementa, the London based office of the Integral Group, called ‘Out of the Blue’ will shortly be available. This study investigated in-depth, through industry-based data, the issues of colour on occupants and what differing dynamic glass products can achieve. It is a highly recommended read.
Overall, dynamic glass acceptance by the market is driven by performance, switching speed, colour neutrality and value. The product that will combine all of these aspects will generalize the use of dynamic glass in façades all around the globe. That’s why eyrise™ becomes more attractive today within the architectural design community.
How are these units to be controlled and connected? Already eyrise™ dynamic glass interfaces data from sensors and integrates with BMS hardware to allow swift responses when needed.
At the end of 2018, eyrise™ glass was installed in a large project in Oslo. The Orkla City project designed by NSW architects with façade contractors Staticus. During visits to the project this summer, it was noticeable that the building occupants were going about their business in a very comfortable, west-facing, environment without any discomfort from solar heat gains, or glare. More interestingly the people occupying and using the space were extremely surprised when the manual override was employed and the glass was made to lighten and darken in real-time. Immediate questions were asked, “What’s happening?”. “We didn’t know the glass was capable of this”. Nice to hear when the glass had been doing exactly what it should be doing, on a daily basis, for the last 9 months through both winter and summer. That is, subtly adjusting to the optimal conditions required. No one seemed to have noticed. Success for eyrise™ dynamic glass.
Controllability and user interface will be the drivers for any glass that wants to be dynamic for façades to work efficiently. Eyrise™ solution allows for unique controllability to suit occupiers and owners specific needs. It is currently the only dynamic glass with this full range of operational variations and future possibilities. Some would say eyrise™ is the only technology that can lead change.
Like high-performance coatings of the glass world today, an electrochromic glass has limitations in where the technology may go. Eyrise™ glass, on the other hand, is rapidly starting to make a mark in façade design. Don’t forget that this is the technology behind every smartphone and tablet we use today. Remember when we all got our hands on the first smartphones, and look at where we are right now with today’s smart devices. How quickly that technology has developed. This is exactly the world where Eyrise™ glass is coming from.
Eyrise™ liquid crystal glass has the ability to further develop and enhance the existing product range of truly dynamic glass. Thus enabling high-performance energy-efficient façades to remain at the forefront of the architectural intent. All this whilst keeping the desired transparency we crave in today’s society. Presently eyrise™ glass is already making this happen. With the design world quickly adapting the principles of eyrise™, great changes in dynamic façade designs are swiftly coming.
This article was originally published in IGS Magazines Winter 2019 Issue: Read the full Magazine here for more thought-leadership from those spearheading the industry
Bruce is an architect with a passion for glass and glass technologies. He spent time within the glass industry, learning about glass production and processing, and had a global role for Eckelt Glas looking after such iconic glass projects as Prada Tokyo (Herzog DeMeuron), NYC TKTS Times Square (Perkins Eastman), Swiss Re – aka The Gherkin London (Foster – Partners). After spells at Arup Facades and Dow Corning he is back within the glass technology world at Merck Window Technologies helping to create a future with truly dynamic glass using Liquid Crystal innovations.