How façade designers embracing natural light to achieve energy efficiency targets
Prior to the invention of electricity, our ancestors used to rely on the sun as their prime source of illumination, making do with the feeble light provided by lamps or candles when night fell. While ‘daylighting’ is a modern term, natural light has in fact always been a major factor in architecture.
Stretching from Ancient Persia and Greece through to the huge stained-glass windows in neo-Gothic churches, windows and natural light have been crucial components in mankind’s design and build ambitions. With the lack of artificial light and technological limitations, it’s easy to see why the forebears of the modern construction industry were quick to use sunlight in as many ways as they could.
Many buildings used mirrors to reflect limited natural light sources, creating the illusion of increased space, as seen in many European palaces and museums. In other cases, daylight often shaped the design of buildings, with places of trade and commerce oriented to benefit from maximum sunlight hours, and also using skylights and large windows to increase the amount of light filtering inside.
All that changed in the 20th century, as buildings became taller and larger, making it more and more difficult to use natural lighting alone. Soon there was a massive increase in dependence on artificial light, and windows became smaller and more decorative, rather than sources of illumination. Utilitarianism was the order of the day.
Over the last two decades, however, that school of thinking has been shifting, with more and more architects returning to the concept of natural lighting. Partly driven by changing perceptions and partly by an increased demand for sustainability, energy-efficient design has made an impressive comeback in the 21st century.
Already there are notable examples of architects and designers using facades to create distinctive looks for buildings, while maximising the use of natural light. One is the famous London Gherkin, which uses six light wells behind its glass façade to spread natural light through the building.
The drive for sustainability is also gathering momentum in the GCC. As a result, there are now many more opportunities for façade designers and consultants to push for the use of sustainable alternatives to traditional façade uses, as Matt Kitson, regional director of Hilson Moran Qatar, tells Big Project ME.
“Suppliers are responding to the market. There are now glass products that can vary the solar transmission, in the same time that they can vary the light transmission electronically. Just three or four years ago, they were quite expensive, but now they’re becoming quite commercially viable.
“There is a product called electrochromic glass, which is a smart glass. You can programme it and it can do whatever you need it to do. It tints when you need it to perform, and it becomes more transparent when it doesn’t need to. When you think about it, why hasn’t that been done before? But that’s the way things are going, and I think that’s where buildings are going to be in the next three or four years’ time.”
Hesham Kameshki, marketing and business development manager for Technal Middle East, an international architectural aluminium systems provider, agrees with Kitson about the changing trends in the GCC marketplace, highlighting the increased emphasis on daylighting.
He points out that market demand has been so high that Technal has actually developed an aluminium brise-soleil system called Sunéal to meet market needs. The system provides solar protection, particularly for glass-clad, high-rise buildings, while also enhancing aesthetics and optimising daylighting, Kameshki explains.
“Whether to provide sun protection, control solar heat gain or to optimise on daylighting, our systems provide an ideal solution, particularly for glass-clad high-rise buildings. Our systems give designers and occupants all the comfort they could possibly want in both winter and summer. The natural light is diffused with neither heat nor solar radiation, while the concept adds an aesthetic value by transforming facades to their best advantage.”
Highlighting the changing attitudes towards sustainability and energy efficiency, Matt Kitson points out that on the day of his interview with Big Project ME, he is meeting with a client to conduct a workshop for a project in Qatar in its concept stage. The topic of the workshop? Sustainability, a topic of conversation that wouldn’t have even been on the table five years ago, he says.
“I’ve seen in recent times in the UAE and also in Qatar – and to a certain extent in Saudi Arabia – that people are starting to think a little bit more about sustainability and energy, in terms of the façade, because of what’s happening with certain bits of legislation. Interestingly, it’s being driven along the same lines as a lot of European models. You’ve got the Dubai Green Code, which is a start.
“There’s also an aspiration here amongst certain developers to go for a LEED rating. A big part of LEED is the energy credit, and you can’t really get that unless you have a very good performing building skin. Qatar is no different to the UAE. It has its own Global Sustainability Assessment System, which it has developed.”
While attitudes in the Gulf are changing to embrace greater sustainability, which will no doubt help the adoption of more energy-efficient facades, the technology being developed for these systems isn’t stopping. In 2013, researchers at the University of Cincinnati announced that they had developed glass façade technology that cut energy costs by brightening up rooms with natural light. Called SmartLight, the system is designed to direct sunlight into dark, dingy rooms deep in a building’s interior, without using wires, ducts, tubes or cables, by harnessing and storing excess light to provide energy for electrical systems.
The SmartLight system works through minute electrofludic cells that are filled with fluid that has optical properties as good or even better than glass. The surface tension of the fluid can then be rapidly manipulated to transform the cells into lens or prisms to control sunlight passing through them. This manipulation is powered by photovoltaics within the cells, and requires 10,000 to 100,000 times less power than used by a traditional incandescent lightbulb.
The cells can then be formed and positioned to direct sunlight where needed – whether it’s onto the ceiling to provide ambient lighting, or to a localised workspace, or even to a ‘light- locked’ room that has its own electrofluidic grid.
While this technology is still in the early stages of development and implementation, there are other technologies that both Kitson and Kameshki predict will shape the way building facades are designed and built.
Sunéal can provide enhanced efficiency when photovoltaic cells are integrated on its aluminium blades, says Kameshki. “The photovoltaic blades provide privacy, as well as electricity power generation with 15% efficiency. Blades come in angles of 15, 30, 45 and 60 degrees depending on the orientation of the façade and the geographical zone of the building to ensure maximum efficiency. The photovoltaic modules integrated in the Sunéal blade are made to the highest market standards and meet the IEC 61730 [safety] and IEC 61215 [performance] standards.”
Meanwhile, Kitson says that he’s convinced that electro-chroming is set to be the next big thing in glass facades. He points out that with the current building boom in Dubai and Doha, there is a huge opportunity for developers to marry their sustainability goals with interesting and inventive technology.
“I think the discussion about sustainability and design is propagating down the food chain, starting from clients. But there’s a common theme [being discussed] about being efficient, and there’s a big debate ongoing. One of the things that has come out is that ‘Let’s not say that such and such should be like this’. Because then everything is nice and green and efficient [but the same],” he warns.
“Designers still need to have a bit of flair, and if everything was the same, you wouldn’t have cities, you’d have horrible, prison-like decors! So you’ve still got to have this creativity, but what was also really refreshing is that people are saying, and talking about, some really interesting ways of doing stuff. It’s good to know that the creativity is out there.
“I think that the designers that will survive are the ones that will create more. And I think you’ve got to be a little more than that. Maybe the industry had become a bit lazy and it was a case of cut and paste and cut and paste.
“You can’t really do that anymore. If you want to survive, if you want to be a different organisation, if you want to be perceived as a quality organisation, then you’ve got to really think about your skin design and your façade design,” Kitson concludes.