SAGE Electrochromics makes specialized glass that can be electronically tinted on demand. The glass, primarily intended for use in windows, comes with a special nano-scale coating that helps it plug into a building's automated control system -- giving a structure, in effect, "smart skin" that can tint as the sun rises.
Twenty-two years ago, chief executive John Van Dine walked away from his job as a chemical engineer at a photovoltaic solar panel company to found a startup to use solar technology in a completely new way.
I spoke to him last week about how electrochromic glass works, how it can help keep large windows in the green building equation and why the Middle East is especially interested.
SP: How did Sage get started?
JVD: I started the company 20 years ago. Before I founded Sage, I was involved in the technology end of thin-film photovoltaics -- solar cells on glass. I was part of that for over a decade.
In my work, I started to learn about other materials -- "smart" materials that could change their optical properties. It intrigued me. I did some research into electrochromic materials and I convinced myself that an electronically-tintable window had the potential to save more energy on a unit-area basis than PV can produce, particularly when we're talking about building-integrated PV, where the angle isn't optimized all the time.
So I started Sage. Went through a long development period -- materials, device, process, device development. From R&D to a small pilot line to a high-volume manufacturing operation. This is our fourth stage of development.
SP: Many green building schemes call for a reduction in the size of windows, to better seal the building envelope. Can "smart glass" help keep large windows around?
JVD: These materials can not only save energy, but the balance of systems is there already. We're not going to stop building buildings out of glass.
We all reason that we have glass in buildings because people occupy buildings and want to feel connected to the outdoors. This feeling of not being closed in. Everybody wants the corner office with windows. But glass is one of the more energy-inefficient building materials. It lets heat in in the summertime and lets it out in the wintertime. Glass needs to be maintained. Once in awhile it breaks. Why do smart people design buildings and continue to put glass in the envelope? They want that connection.
The irony is that, to deal with the glare, we put shades and blinds on -- you no longer have that connection to the outdoors. To deal with the heat, we use air conditioning. We heavily tint the glass, meaning we don't harvest the sunlight during the day. The solution to all of this is to have glass that we can change its properties so that when we have direct sunlight we can heavily tint the glass electronically and still maintain the view and connection to the outdoors. This is what's so important. As sun hides behind clouds, we have the glass in a high-transmission condition. And it's all done with no moving parts.
There are three benefits of electrochromic glass:
- Energy savings, in terms of reducing [HVAC] and lighting load.
- It allows the architect to design buildings more sustainably.
- Environmental savings, because you reduce the tonnage of the air conditioning equipment. Those materials don't need to be there, on-site.
Plus, electronically-tintable glass enhances the human experience of buildings. You can sit next to a window with direct sun on it and will not get hot.
SP: We all crave natural light. Have you been able to quantify a productivity improvement with tintable glass?
JVD: We have not, but there are a number of studies that show that natural sunlight allows for a more productive environment.
The other part is that we're now getting customer feedback. It's better than they thought it could be.
But to your point, we are working on generating additional documentation on this.
SP: How does electrochromic glass work? Break it down for us.
JVD: The materials are part of a family of chromogenetic materials -- electrochromic, thermalchromic and photochromic. Photochromic [materials] respond to UV in sunlight; they're often in sunglasses. Thermalchromic responds to a temperature transition -- the material responds to a certain temperature and transitions. Electrochromic is controlled with a low DC voltage. The level -- between 0 and 3 -- affects the level of tint.
We take a regular piece of glass and on it we deposit a series of thin films made of electrochromic materials. By building up layers, we create an electrochromic device. The total thickness is less than a micron -- one hundredth of the width of a human hair. Buried in the frame, where you can't see, are busbars that have voltage in them.
Today, you run wires through the framing system. Three volts DC. We are working on wireless systems that we will introduce to the market.
SP: Can you combine the technologies into glass that both electronically tints and generates energy, via solar thin film?
JVD: That's the holy grail right there. It's not only technically possible, it's desirable. It's where we're going. The output of a thin film PV panel is DC and the input of electrochromic glass is, too. We've already done it and we're planning to take it to the next step and integrating it.
SP: Where do you improve? Faster switching? Fewer wires?
JVD: We're early on that technological level. First of all, we want a totally wireless system. Now that you've brought power to the glass, you can think about other electronics built into the glass -- a thermometer or a display.
Taking the glass and making it more and more transparent -- more like pure glass. Sage glass in its fully clear condition isn't as transparent as pure glass.
We could look at switching speed to make it faster, but we can't make it too fast because your eyes need to adjust.
Another way to reduce energy is to, on wall to ceiling glass, zone it -- tint glass where you want to stop direct sunlight on the top but not the lower part. Making that more built into the design of the building in general; more refined.
SP: I understand the Middle East is very interested in electrochromic glass. Many of those countries are sitting on vast oil reserves. What's the rush?
JVD: I just got back from a trip in the Middle East and they're looking to do the same thing -- restricting the amount of glass in the building unless you can meet certain requirements. There, their power is electrical power generated by oil and is subsidized. It could have been sold in the open market for a great deal more.
It's a real challenge because the private sector of the U.A.E. and Saudi Arabia are used to subsidized energy. You have to run air conditioning there all day. When I was there, it was 120 degrees [Fahrenheit]. They can't just take that away from them. They realize that what they can change is government institutional buildings. They're very acutely aware of the lost opportunity.
SP: Next steps: do you go big and sell to the Middle East, or sell to a North American market still in the wake of a recession?
We first have to believe that we have a global technology. That's why we partnered with [major glass manufacturer] Saint-Gobain. We're developing sales and marketing teams here and our new partners are very strong in Europe.
Other parts of the world, we're working through that now. We know we need to be in Asia and China. The faster we grow and disseminate this technology the faster it improves and gains benefits.
SP: And what about glass skyscrapers in cities? They seem to be the most suitable applications to show the benefits of your product.
JVD: Not here in North America, but new construction is still going up in Asia and the Middle East. The Olympics plans in Doha, for example.
On the other hand, there are buildings going up. People are doing renovation work. In the past 12 months we did a project with Ball State University, a new room they built, an open area entryway with a big skylight. It was unbearable, the heat and glare [from the plain glass skylight]. They ended up using our glass instead.
Another example is we recently did the new wind turbine facility for Siemens in Hutchinson, Kansas. They have lots of nice glass in this building and did a side-by-side comparison and chose us. One retrofit, one brand-new building.
SP: Have green building codes discriminated against windows?
JVD: There is an understanding today that glass relative to other building materials is energy inefficient. Double-pane windows, triple-pane windows and so forth provide better insulation. But the code bodies are still looking at it and saying static glass is still a weak link in the building. There are meetings going on about limiting the amount of glass in the envelope of a building unless you can meet certain performance requirements.
SP: Any glass prejudice out there?
JVD: That has not happened yet.
This post was originally published on Smartplanet.com