Windows are one of the least energy efficient elements in a building. Heliotrope Technologies seeks to change the “smart window” technology market to increase energy efficiency through the transmission of heat and light with the use of its specialized film.
How Does it Work?
Smart window technology has been available for ten years which switches the window from light to dark. Heliotrophe’s technology has gone one step further. Its coatings can alter both the light and heat transmission simultaneously or independently.
According to the Company:
“Windows with the Heliotrope EC coatings can switch reversibly between three states: transparent,heat blocking, and heat and light blocking. The company refers to these states as Bright, Cool, and Dark. A small voltage controls the optical state of the device. Minimal power is consumed during switching and almost none is used to maintain either of the two solar blocking states. This yields great flexibility for system integration and low cost installation.”
In large commercial buildings, the voltage response would be integrated in a building management system, which would adjust dynamically from the feedback from temperature, light, and other information deployed by the building’s sensors.
The science behind the windows
When a current is supplied to extremely tiny crystals of indium tin oxide, it acts as a heat blocker. In turn, the heat blocker stops 35 percent of the infrared radiation passing through it.
However, when the Company added a layer of indium tin oxide in glass made out of niobium oxide, the window darkened. When the researchers added both materials together and used electricity, the material blocked more than 50% percent of heat and 70% of light that passed through the glass.
The coating is encapsulated within the outer pane in a double pane window and consists of two pieces of glass laminated together. Although the coating is not exposed to the elements, edge sealants will be required to preclude long-term moisture intrusion.
What About Price?
Current electrochromic glass costs $200 a square foot. Heliotrophe’s goal is offer its glass technology for $100 a square foot.
“Price remains one of the biggest hurdles for wider adoption of smart window technology, and we believe we have the solution,” said Jason Holt, COO and co-founder of Heliotrope. Full commercialization will be achieved in partnership with one or more established manufacturers of building glass or finished windows. This business model avoids the high capital requirements of independent manufacturing and allows for easier integration into large scale manufacturing and distribution of windows and building glass.”
To elaborate further, Holt states via email,
“We will reduce the cost of dynamic windows by use of a solution-based fabrication process. This is in contrast to the vacuum, vapor deposition processes used in industry currently. Almost 50% of the cost of a “smart” double pane window (to an installer) lies in the pane of glass containing these “smart” films, so cost reductions in the film fabrication process have significant impacts on window costs. Our scale-up/commercialization model has yet to be completely mapped out, but we intend to do so in such a way as to preserve our cost advantage over other “smart” film technologies”
This technology could easily replace the need for automated window shades and other shading devices, which in essence decreases building improvement costs.
“In terms of payback, the answers depend on many variables. However, we believe there is a scenario where Heliotrope’s cost advantage would make it nearly cost neutral (i.e. payback of few months) as compared to conventional windows using blinds,” Holt elaborates via email.
The Company stated in a recent press release that it plans to send samples of its commercial product in the fourth quarter of 2013.
“Our goal is to make larger-format devices, potentially large enough for a skylight, in the next 3-4 years,” Holt said.
Interestingly, the “smart” window technology’s market share of architectural glass industry is only 1 percent. So, will this technology be embraced? Time will tell if Heliotrope’s technology catches on.
Join the Conversation:
- Do you think this a viable technology that will be embraced by the window industry?
- Do you think this technology is too expensive?
Photo by permission of Lawrence Berkeley National Laboratory